steering system maintenance guidelines · pdf filepoppet resetting single gear ... seal is...
TRANSCRIPT
TRW AutomotiveCommercial Steering Systems
Steering System Maintenance Guidelines
Hazard Warning Definitions
A warning describes hazards or unsafe practices which could result in severe personal injury or death.
Throughout this troubleshooting guide, test procedures are recommended to help locate the cause of each complaint. While performing these tests,
TRW advises that you TAKE NECESSARY PRECAUTIONS when working with internal vehicle components and hot hydraulic fluids.
A caution describes hazards or unsafe practices which could result in personal injury or product or property damage.
A note gives key information to make following a procedure easier or quicker.
Notice
Power Steering System Analyzer (PSSA) Gauge
This guide was prepared for the purpose of providing general advice concerning the diagnosis and correction of commercial vehicle steering related problems. This guide is intended for the use of properly trained, professional mechanics, NOT “Do-it-Yourselfers”. Also, this guide should be used in conjunction with service manuals provided by both the vehicle and component manufacturers. Diagnosis and correction of commercial vehicle steering related problems should only be handled by properly trained, professional mechanics who have the proper equipment, tools, instructions and know-how to perform the work properly and safely.
Some of the tests in this manual require the use of a PSSA. This device is a combination flow meter, shut-off valve, and pressure gauge. This tool will allow you to measure flow and pressure, and provide a load on the pump through the hydraulic lines of the steering system. This tool is required to correctly analyze a steering system. TRW recommends that you DO NOT BEGIN TROUBLESHOOTING A STEERING SYSTEM WITHOUT THE USE OF A PSSA. If you are not sure how to use a PSSA, you may refer to the video available through our website at: www.trucksteering.com. This video compliments the tests in this book which require the use of the PSSA.
© TRW Inc., 2008
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Table of Contents Preventative Maintenance Guidelines ............................................... 5 Approved Fluids and Grease ................................................................. 6 Input Shaft Seal Replacement .............................................................. 7 Seal Removal .................................................................................... 8 Seal Inspection ................................................................................. 9 Sector Shaft Adjustment ...................................................................... 10 Poppets ................................................................................................... 11 Resetting Criteria ........................................................................... 11 System Identification ...................................................................... 12 Initial Poppet Setting Procedure .................................................... 12 Poppet Resetting Single Gear System ........................................... 13 Poppet Resetting Mirror System .................................................... 15 Poppet Resetting Reverse System ................................................. 17 Main Gear Adjustment ................................................................... 18 Rotary Cylinder Adjustment ........................................................... 18 Air Bleeding the Steering System ..................................................... 19 Visual Identification ........................................................................ 19 Auto Bleed Gears ........................................................................... 19 Maual Bleed Gears ......................................................................... 20 Flushing the Steering System ............................................................. 21 Power Steering System Analyzer (PSSA) Application and Use .. 23 Installing the PSSA ......................................................................... 23 Power Steering Pump Test ............................................................. 25 Poppet Trip Pressure Test ............................................................... 26 Test Result Charts .......................................................................... 28 PSSA Installations (Various Gear Configurations) ......................... 29 Linkage Inspection, Maintenance, Replacement, and Adjustment ........................................................... 30 Maintenance Checklist ................................................................... 30 Tie Rod End Replacement ............................................................... 31 Draglink - One End Adjustable ....................................................... 32 Draglink - Two end Adjustable ....................................................... 33 Tie Rod Tube Assembly - One End Adjustable ............................... 34 Tie Rod Tube Assembly - TwoEnd Adjustable ................................ 35 Drop Center Tie Rod Tube Assembly - One End Adjustable ........... 36
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Lubrication guidelines for tie rod and draglink ends.• Highway(Every20,000miles)• Pick-up/Delivery(2x/month)• HeavyDuty(Every500hours)• SevereDuty(Every250hours)Usehandoperatedgreasegun.
Tighten tie rod end pinch clamp bolt to approved OEM torque specification.(4x/year)
Tighten pitman arm connection to approved torque specification.(4x/year)
Check cotter pin at slotted nut on all tie rod and draglink ends. Check nut torque and replace cotter pin, if missing.(At each lube cycle)
Replenish lube under dirt and water seal.(2x/year)
Inspect U-joint and pinch bolts. Torque to approved specification.(4x/year)
If equipped with grease fittings, lube intermediate column U-joints and slip joint.(At each lube cycle)
Drain reservoir and replace filter.(1x/year - Highway, 2x/year - Severe Duty)
Routinely check oil level. See list of approved hydraulic fluid on following page.
Tighten hose clamps and inspect all hydraulic hoses and connections for leakage. Bleed air from the system, if required.(2x/year)
Lubricate at trunnion grease fitting with hand operated gun only.(At each lube cycle)
CAUTION
Neverhighpressurewashorsteamcleanapowersteeringgearwhileonoroffthevehicle.Thiswillforcecontaminantsintothegear,especiallythroughthesidecoverventplughole,inputshaftseal,andoutputshaftsealareas.Thesecontaminantscoulddestroyseals,bushings,andbearings.Resultinginareductionofsteeringgearperformance.
Preventive Maintenance Guidelines
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Approved Hydraulic Fluids
Thetypeoffluidusedinthepowersteeringsystemisvitaltoextendboththelifeofthecomponentsanditsseals.ItisnecessarytoutilizeasteeringsystemfluidthatisspecifiedandapprovedbythevehiclemanufacturerandalsocomplieswithTRWCommercialSteeringSystems’recommendation.
Itisrecommendedthatanyfluidspecification,outsideofthecompliantlubricantlisted,bereviewedbyTRWtoensurethecompatibilitybetweenthecomponentandfluidtypebeingused.
TRWrecommendsusingoneofthefollowingfluidsinthepowersteeringsystem.
AutomaticTransmissionFluid •DexronII •DexronIII •FordMercon
NOTE
Thesteeringsystemshouldbekeptfilledwithoneoftheabovefluids.
CAUTION
Completelyflushthesteeringsystemwhenchangingtoanotherfluid.Replacethereservoirfilterafterflushingthesystem.Fillthesystemwithoneoftherecommendedfluidsabove,only.Donotmixfluidtypes.Anymixtureoranyunapprovedoilcouldleadtosealdeteriorationandleaks.Aleakcouldultimatelycausethelossoffluid,whichcouldresultinalossofpowersteeringassist.
Besuretobleedtheairoutofthesystembeforeputtingthevehiclebackintoservice.
Approved Grease
#2NLGIextremepressure,lithiumbased,molyfilled,heavydutygrease.MobilSHC100foruseongreasableintermediatecolumnslipjoint
NOTE
Morespecificproceduresandintervalscanbefoundinthevehiclemanufacturersservicemanual.TheseproceduresareTRW’sgeneralguidelinesforsteeringrelatedpreventivemaintenance.Servicemanualsandtechnicalbulletinsarealsoavailablethroughourwebsite.
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Input Shaft Seal Replacement
Detecting Input Shaft Seal Leakage
TRWpowersteeringgearsincorporatean“Umbrella”styleexternaldirtsealbetweenthesteeringshaftU-jointandthehousingofthesteeringgear.ThecavityunderthissealisfilledbyTRWatassemblywithaspecialgreasetoinhibitcorrosionoftheinputshaftneartheinputshaftseal.Sincethis“Umbrella”doesnotpositivelyinterferewiththemainhousing,someamountofthegreaseunderitcanmigratetotheexternalhousingsurfaces.Overtime,especiallyunderelevatedoperatingtemperatures,someofthebaseoilinthegreasecanseparatefromthecarrier.Thisthinfilmofoilcanspreadovertheupperpartofthegear,attractdustanddirt,causingtheappearancethattheinputshaftsealisleakingpowersteeringfluid.
Initialinspectioncriteriatodetermineiftheinputshaftsealisleaking:• Ifthedust/dirtinthisareais“dry”(notsaturatedornotdrippingfluid)theinputshaftsealisoperatingproperly.
• Ifithasnotbeennecessarytoreplenishthereservoirfluidlevelfrequently,theinputshaftsealisoperatingproperly.
• Ifthedust/dirtis“Wet”orappearsas“cakedmud”thenacloserlookisrequired.
Additionally,thefollowingareothercausesthatmaypresentfalseindicationsofinputshaftsealleakage.• Lookforsignsofover-greasingtheU-jointyoke(whichcanspreadtotheinputshaftsealofthesteeringgearovertime,
creatinganappearanceofleakage),leakingpowersteeringhoses(theyareusuallycoveredwitha“wetmud”whentherubberpartstartstofail).
• Oilleakscanoccuratthehosefittingswhichgiveafalseindicationofasteeringgearinputshaftsealleak.
• Onmanyvehicles,thereservoirislocateddirectlyoverthesteeringgear.Overfilledorleakingreservoirscandripontothesteeringgearresultinginafalseindicationofaninputshaftsealleak.
Inordertodetermineiftheinputshaftsealisleaking,dothefollowing:1. Wipedowntheareaofthesteeringgeararoundtheinputshaftsealandhoseconnections.
CAUTION
Neverhighpressurewashorsteamcleanapowersteeringgearwhileonoroffthevehicle.Thiswillforcecontaminantsintothegear,especiallythroughthesidecoverventplughole,inputshaftseal,andoutputshaftsealareas.Thesecontaminantscoulddestroyseals,bushings,andbearings.Resultinginareductionofsteeringgearperformance.
2. Withthevehicleparkedandatemperaturegaugeinsertedinthereservoir,observetheinputshaftsealareaandhoseconnectionswhilerunningtheengineandsteeringthevehiclefor5-10minutes.Theoiltemperatureshouldbe130°-160°Fwhenobservingsealareaandhoseconnections.
CAUTION Donotletoiltemperatureexceed250°Fwhileperformingthismaneuver.
Conclusions:• Iffluidleakageisnotedfromthereservoir,hose,fittings,orotherplumbingconnections,repairtheproblemandretest.
• Ifnofluidleakageisobserved,thentheappearanceofleakageislikelyamigrationofgreasenotasealfailure.
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Seal Removal Thisprocedureusesthevehicle’spowersteeringpumptoforceouttheinputshaftseal.Tousethisprocedure,thepowersteeringpumpshouldhaveaminimumof1,500psiavailable.1. Placeadrippanonthefloortocatchtheoil.
2. Disconnectreturnline(Figure1)fromthesteeringgear.Plugthereturnlineandcapthereturnportofthegearwithhighpressurefittings
3. Disconnecttheintermediatecolumnfromthesteeringgear’sinputshaft.Cleantheinputshaftendofthesteeringgear.
4. Removethedirtandwatersealfromthesteeringgear.
5. Wipeoutthegreasefrombehindthedirtandwaterseal.
6. Insertasmallscrewdriverintothenotchformedintheendofthespiralretainingring(Figure2).Removetheretainingring.Becarefulnottoscratchtheborewiththescrewdriver.
7. Sliptheintermediatecolumnbackontotheinputshaftwiththepinchboltinstalled,butnottightened.
8. Tieacleanshoptowel(Figure3)aroundtheinputshaftareatoreduceoilspatter.
9. Checkthereservoir,andaddfluidifnecessary,untilthelevelisatthe“full”markonthedipstick.Donotmixfluidtypes.
CAUTION
Anymixtureoffluidtypes,oruseofanyunapprovedfluidcouldleadtosealdeteriorationandleaks.Aleakcouldultimatelycausethelossoffluid,whichcouldresultinalossofpowersteeringassist.
10. Withthevehicleinneutral,momentarilyturnthestarter(quicklyturnofftheengineifitstarts).
11. Removetheshoptowel.Disconnecttheintermediatecolumn(Figure4),andremovetheinputshaftseal(Figure5).
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
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Seal Inspection
1. Checkthesealareaofthevalvehousingforanysealfragments.Removealldebris.
2. Checkthesealforheatdamage.Ifthesealisstiffandbrittle,andnotpli-ablelikethenewseal(Figure6),itisprobablyheatdamaged.Determineandfixthecauseofexcessiveheatinthesteeringsystem.
Seal Installation
1. Putcleangrease(providedinthekit)ontheinsidediameterofthenewinputshaftseal,andplaceitovertheinputshaft.
2. Placesmalldiameter-endofthesealinstallertool(J37073)overtheinputshaftandagainsttheseal(Figure7).Tapthesealinstallertooluntilthetoolshoulderissquareagainstthevalvehousing.Removeanysealmate-rialthatmayhaveshearedoffinthesealboreorretainingringgroove.
CAUTION Donotuseasockettoinstallthissealbecauseyouwillnotbeabletocontrolsealinstallationdepth,possiblycausingaleak.
3. Insertnewretainingringintothegroove(Figure8).
4. Packtheendofthevalvehousingborearoundtheinputshaftwithgrease(providedinthekit).Choosethecorrectsizeofthenewdirt&watersealbycomparingittotheoldseal,orbymeasuringthemajordiameteroftheinputshaftserrations(seechartbelow).Applymoregreasetotheback-sideofthenewdirt&watersealandinstallitovertheinputshaft(Figure9).Seatitinthegroovebehindtheserrationsandagainstthevalvehous-ing.
SealPartNumber SerrationSize MajorSerrationDiameter 478044 13/16”x36 0.807/0.799 478060 7/8x36 0.866/0.857 478050 1”x36 0.987/0.977 478050 1”x79 1.008/1.000
5. Reconnecttheintermediatecolumn(Figure10)totheinputshaftandtightenthepinchbolttotorquelevelspecifiedbythevehiclemanufacturer.
6. Reconnectthereturnlinetothesteeringgearreturnport.Then,refillthereservoirifnecessary.
7. AirbleedthesystemusingtheprocedureoutlinedbyTRW.
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
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Sector Shaft Adjustment
Thesectorshaftadjustmentprocedurecanonlybecompletedonthevehicleiftheadjustingscrewandjamnutareaccessible.Thisnutislocatedonthesidecover.
1. Withtheengineon,rotatethesteeringwheeluntilthewheelsarestraightaheadandthetimingmarkonthesectorshaft(Figure1)linesupwiththemarkonthehousing.Thelineonthesectorshaftshouldbeata90°anglefromtheinputshaft.Thesectorshaftisnowcenteredandpreparedfortheadjustment.
2. Turnthevehicleoff.
3. Removethedraglinkfromthepitmanarm.
4. Toavoidresettingthepoppets,donotrotatetheinputshaftmorethan11⁄2turnsfromthe“centered”positionwhilethedraglinkisdisconnected.
5. Whileinthe“centered”position,graspthepitmanarm(Figure2)andgentlytrytorotateitbackandforth.Ifloosenessorlashisfeltatthispoint,thesectorshaftisoutofadjustment.
6. Loosenthejamnut.
7. IfnolashwasdetectedinStep4,turntheshaftadjustingscrew(Figure3)counterclockwiseuntilyoufeellashattheoutputshaft.
8. Slowlyturnthesectorshaftadjustingscrewclockwiseuntilyoufeelnolashusingonlyslightpressureonthepitmanarm,about10ft•lboftorque.
9. Holdtheadjustingscrewinplace,andtightenthejamnut.Torquethejamnutto43ft•lb(58N•m).
10. Turnthesteeringwheel1⁄4turneachsideofcenter,thenbacktocenterandrecheckthepitmanarmforlash.Ifyoustillfeellash,repeattheprocedure.
11. Reconnectthedraglinktothepitmanarm.Torquethenuttoapprovedvehiclemanufacturer’sspecificationsandreinsertcotterpin.
12. Maintaingreaseinthesectorshaftbearingthroughthegreasefitting(Figure4)inthehousingusingonlyahandoperatedgreasegun.Addgreaseuntilitbeginstopurgepastthedirtandwaterseal.
CAUTION
Donotuseapowergreasegunbecauseitwillsupplygreasetoofast;thiscouldadverselyaffectthehighpressuresealandcontaminatethehydraulicfluid.
Figure 1
Figure 2
Figure 3
Figure 4
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Poppets
What are Poppets?
Poppetsarepressureunloadingvalves,insidetherackpiston,that“relieve”just beforeafullturnismadeineachdirection.Whenpoppetsaresetorresetcorrectly,systempressurewillbereducedbeforetheaxlestopboltcontactstheaxlestopinbothdirections.
Poppet Resetting Criteria
PoppetsonTRWsteeringgearsdonothavetobereset,unlessthevehiclehasbeenmodifiedinsuchawaythatwheelcutforthevehicleisdecreased.
Ifthegearhasafixedstopboltandyouaredecreasingthevehicle’swheelcut,youwillneedanewpoppetadjustingscrewandjamnut.Ifwheelcutisbeingincreased,thepoppetswillresetautomatically.Inthiscase,refertothePoppetSettingprocedure.
Examplesofmodificationsthatrequirepoppetresettinginclude:
•Changingtolargertires •Reducingwheelcutforanyreason •SteeraxleU-boltswerebentorbroken •Ifthepitmanarmwasmistimedandwasretimed •Axlestopboltsweredamagedandhavebeenreplaced •Orwhenthesteeringgearhasbeenmountedonadifferentvehicle.
NOTE
UsethePOPPETRESETTINGPROCEDURESonlyifyoumadeamodificationtothevehicleasoutlinedinthelistabove.
Steering Gear - Section View
1. FixedStopBolt2. LowerPoppet3. LowerPoppetSeat4. LowerPoppetSleeve5. Spring6. PushTube7. UpperPoppetSleeve8. UpperPoppetSeat9. UpperPoppet10. ValveHousing11. InputShaft12. Valve13. RecirculatingSteelBalls14. RackPiston15. WormScrew16. PitmanArm17. TimingMarks18. SectorShaft19. Housing
1 32 4 5 6 7 8 9 10
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System Identification
Beforeresettingpoppetsonasteeringgear,youmustidentifythetypeofsystemwithwhichyouareworking.
Forsinglegearandagearwithlinearassistcylinders,usetheSingleGearPoppetResettingprocedure.
Onadualgearsystem,youmustdeterminewhetherthesystemhaseithermirrorimagegearsorreversedimagegears.Theproceduresareslightlydifferentforeachtypeofsystem,sousethefollowingcriteriatoidentifywhichmethodappliestoyourapplication.
1. Parkthevehiclewiththewheelsturnedallthewaytotheaxlestopineitherdirection.Turnthevehicleoff.
2. Lookattheoutputshafttimingmarknearestthehousingpistonboreonthemaingear.Isthismarkpointingtowardthepoppetscreworawayfromit?
3. Nowchecktheoutputshafttimingmarknearestthehousingpistonboreontherotarycylinder.Doesitpointtowardthepoppetscreworawayfromit?
UsetheMIRRORSYSTEMprocedureifthetimingmarkspointtooppositeendsofthegears.
UsetheREVERSESYSTEMprocedureifbothtimingmarkspointtowardthepoppetscrewsorbothpointtowardtheendoppositethepoppetscrews.
Initial Poppet Setting Procedure
Forthisproceduretoworkcorrectly,youmusthave1)AneworremanufacturedgearreceivedfromTRWoryourvehiclemanufacturer’saftermarketsystem,or2)ausedgearonwhichpoppetseatshavebeenreplacedorresetduringgeardisassemblyandassemblyprocedures.Also,afixedstopboltorapoppetadjustingscrewmustbepartofthesteeringgearassembly.
Tosetthepoppetsonaneworremanufacturedsteeringgear,followthesesimplesteps.
1. Makesuretheaxlestopboltsaresettovehiclemanufacturer’swheelcutorclearancespecifications.
2. Raisethefrontendsothesteeraxletiresareofftheground.
3. Starttheengineandletitidle.
4. Steerthevehicleininonedirection,untilyoucontacttheaxlestop.Pullhardonthesteeringwheel.
5. Now,steerthevehicleintheoppositedirectionuntilyoucontacttheaxlestop.Again,pullhardonthesteeringwheel.
6. Turnthevehicleoff.
Rotary Cylinder Main Gear
Poppet Screws
Rotary Cylinder Main Gear
Poppet Screws
Reverse System
Mirror System
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Single Gear Poppet Resetting Procedure
1. Settheaxlestopstovehiclemanufacturer’swheelcutorclearancespecifications.
2. Makesuretheengineisoffandtheroadwheelsareinthestraightaheadposition.
3. Removeanddiscardthepoppetfixedstopboltandwasher(Figure1,ifequipped)fromthelowerendofthehousing.Ifthegearhasapoppetadjustingscrewandjamnutthatneedtobereplaced,removeanddiscardthematthispointalso.
4. Ifanewpoppetadjustingscrewandnutarebeingused,turnthescrewintothenon-sealingendofthejamnutuntiltheAllendriveendofthescrewisflushwiththenut(Figure2).
CAUTION
BesuretheAllendriveendofthescrewisnotbelowthefaceofthenut.Failingtokeepitflushwiththefaceofthenutwillcausethepoppetseatflangetobreaklateronduringthisprocedure.
5. Iftheadjustingscrewisalreadypartofthesteeringgear(Figure3),backthenutoffoftheadjustingscrewuntilitisflushwiththeAllendriveendoftheadjustingscrew.
6. TurnthenewadjustingscrewandjamnutintothehousinguntilthenutisfirmlyagainstthehousingusinganAllenwrench.Tightenthejamnutagainstthehousing.
7. Refillthesystemreservoirwithapprovedhydraulicfluid.
CAUTION
Donotmixfluidtypes.Mixingoftransmissionfluid,motoroil,orotherhydraulicfluidswillcausesealstodeterioratefaster.
8. Placeajackunderthecenterofthefrontaxleandraisethefrontendofthevehiclesothesteeraxletiresareofftheground.
9. Starttheengineandletitrunatidlespeed.
10. Notewhichoutputshafttimingmarkisnearestthehousingpistonbore.
11. Turnthesteeringwheelinthedirectionthatmakesthistimingmarkmovetowardtheadjustingscrewyoujustinstalled(Figure4).Turninthisdirectionuntilaxlestopcontactismade.
12. Pullhard(Figure5)onthesteeringwheel(putupto40lbrimpullona20”dia.steeringwheel)aftertheaxlestopiscontacted.
CAUTION
Donotholdthesteeringwheelatfullturnformorethan10secondsatatime;theheatbuild-upatpumpreliefpressuremaydamagesystemcomponents.
Figure 2
Figure 1
Figure 3
Figure 4
Figure 5
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13. Turnthesteeringwheelintheoppositedirection(endoftimingmarkawayfromadjustingscrew,Figure6)untiltheotheraxlestopiscontacted.
14. Pullhardonthesteeringwheel.
15. Releasethesteeringwheelandshutofftheengine.
16. Loosenthejamnutandbackouttheadjustingscrewuntil1”ispastthenut(Figure7).Tightenthejamnutagainstthehousing.
17. Starttheengineandletitidle.
18. Turnthesteeringwheel,sothatthetimingmarkontheoutputshaftpointstowardtheadjustingscrew,untilaxlestopcontactismade.
19. Pullhardonthesteeringwheelandholditinthispositionfornomorethan10secondsatatime,thenreleasetoallowthesystemtocool.
20. Repeatthisholdandreleaseprocesswhilecompletingsteps21-22.
21. Loosenthejamnutandholditinplacewithawrenchsoitwillnotcontactthehousing.
22. Withsteeringwheelheldatfullturn,turntheadjustingscrewin(clockwise)usingfinger-pressureonly(donotusearatchet),untiltheAllenwrenchstops(Figure8).Atthispoint,theadjustingscrewhascontactedthepop-petseat.Donotattempttoturnitinfarther.
NOTE
Pausetheturning-inprocesseachtimethedriverreleasesthesteeringwheel;continueturningtheadjustingscrewinonlywhilethewheelisheldatfullturn.
23. Backofftheadjustingscrew31/4turnsandtightenthejamnut.Torquethejamnutto35ft•lbs.
Thepoppetshavenowbeenreset.Lowerthevehicleandremovethejack.
Besuretocheckthereservoirandfillifrequired.
NOTE
Donotremovetheadjustingscrew,itisnowpartofthesteeringgearassembly.
NOTE
Thelengthofthepoppetadjustingscrewbeyondthenutmaybedifferentforeachvehicle,butmustbenomorethan11/16”forproperthreadengagement(Figure9).
Figure 7
Figure 6
Figure 9
Figure 8
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Poppet Resetting - Mirror System
Thisresettingprocedurewillworkinmostcaseswithatleast13/4hand-wheel-turnsfromeachsideofcenter.Ifyou’remakingalargereductioninwheelcutandthisproceduredoesnotwork,youmayhavetoreplaceorinternallyresetthepoppetsusingtheproceduredescribedintheappropriategearservicemanual.
1. Settheaxlestopstovehiclemanufacturer’swheelcutorclearancespecifications.
2. Makesuretheengineisoffandtheroadwheelsareinstraightaheadposition.
3. Removeanddiscardthepoppetfixedstopboltandwasher(ifequipped)fromthelowerendofthehousingonboththemaingearandtherotarycylinder.Ifeitherunithasapoppetadjustingscrewandjamnutthatneedtobereplaced,removeanddiscardthematthispointalso.
Ifanewpoppetadjustingscrewandnutarebeingused,turnthescrewsintothenon-sealingendofthejamnutsuntiltheAllendriveendofthescrewisflushwiththenut.
CAUTION
BesuretheAllendriveendofthescrewisnotbelowthefaceofthenut.Failingtokeepitflushwiththefaceofthenutwillcausethepoppetseatflangetobreaklateronduringthisprocedure.
4. Iftheadjustingscrewisalreadypartofthemaingearorrotarycylinder,backthenutoffoftheadjustingscrewuntilitisflushwiththeAllendriveendoftheadjustingscrew.
5. Turnthenewadjustingscrewandjamnut(withoutrotatingthejamnutonthescrew)intothehousinguntilthejamnutisfirmlyagainstthehousing,onboththemaingearandtherotarycylinder,usinganAllenwrench.Tightenthejamnutagainstthehousing.
6. Refillthesystemreservoirwithapprovedhydraulicfluid.
CAUTION
Donotmixfluidtypes.Mixingoftransmissionfluid,motoroil,orotherhydraulicfluidswillcausesealstodeterioratefaster.
7. Placeajackunderthecenterofthefrontaxleandraisethefrontendofthevehiclesothesteeraxletiresareofftheground.
8. Starttheengineandletitrunatidlespeed.
9. Notewhichoutputshafttimingmarkisnearestthehousingpistonbore.
10. Turnthesteeringwheelinthedirectionthatmakesthistimingmarkmovetowardtheadjustingscrewyoujustinstalledonthemaingear.Turninthisdirectionuntilaxlestopcontactismade.
11. Pullhardonthesteeringwheel(put40lbs.rimpullona20”dia.steeringwheel)aftertheaxlestopiscontacted.
CAUTION
Donotholdthesteeringwheelatfullturnformorethan10secondsatatime;theheatbuild-upatpumpreliefpressuremaydamagesystemcomponents.
12. Turnthesteeringwheelintheoppositedirection(endoftimingmarkpointsawayfromadjustingscrewonthemaingear)untiltheotheraxlestopiscontacted.
13. Pullhardonthesteeringwheel.
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14. Releasethesteeringwheelandshutofftheengine.
15. Loosenthejamnutandbackouttheadjustingscrew,onboththemaingearandtherotarycylinder,until1”ispastthenut.Tightenthejamnutsagainstthehousings.
16. Starttheengineandletitidle.
17. Turnthesteeringwheel,sothatthetimingmarkonthemaingearoutputshaftpointstowardtheadjustingscrew,untilaxlestopcontactismade.
18. Pullhardonthesteeringwheelandholditinthispositionfornomorethan10secondsatatime,thenreleasetoallowthesystemtocool.
19. Repeatthisholdandreleaseprocesswhilecompletingthefollowingstepsforboththemaingearandrotarycylinderadjustments.
NOTE
Pausetheturning-inprocesseachtimethedriverreleasesthesteeringwheel;continueturningtheadjustingscrewinonlywhilethewheelisheldatfullturn.
Main Gear Adjustment 1. Withsteeringwheelheldatfullturn,loosenthejamnutonthemaingear,andholditinplacewithawrenchsoitwillnot
contactthehousing.
2. Turntheadjustingscrewin(clockwise)usingfinger-pressureonly(donotusearatchet),untiltheAllenwrenchstops.Atthispoint,theadjustingscrewhascontactedthepoppetseat.Donotattempttoturnitinfarther.
3. Backofftheadjustingscrew31/4turnsandtightenthejamnut.Torquethejamnutto35ft•lbs.
Rotary Cylinder Adjustment 1. Turnthesteeringwheelintheoppositedirection,sothatthetimingmarkonthemaingearoutputshaftpointsawayfrom
theadjustingscrew,untilaxlestopcontactismade.
2. Withsteeringwheelheldatfullturn,loosenthejamnutontherotarycylinderandholditinplacewithawrenchsoitwillnotcontactthehousing.
3. Turntheadjustingscrewin(clockwise)usingfinger-pressureonly(donotusearatchet),untiltheAllenwrenchstops.Atthispoint,theadjustingscrewhascontactedthepoppetseat.Donotattempttoturnitinfarther.
4. Backofftheadjustingscrew31/4turnsandtightenthejamnut.Torquethejamnutto35ft•lbs.
5. Thepoppetsonboththemaingearandrotarycylinderhavenowbeenreset.Lowerthevehicle.Checkthefluidlevelinthereservoirandfillifrequired.
NOTE
Donotremovethepoppetadjustingscrews,theyarenowpartofthemaingearandrotarycylinderassemblies.NOTE
Thelengthofthepoppetadjustingscrewbeyondthenutmaybedifferentforeachvehicle,butmustbenomorethan11/16”forproperthreadengagement.
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Poppet Resetting - Reverse System
Thisresettingprocedurewillworkinmostcaseswithatleast13/4hand-wheel-turnsfromeachsideofcenter.Ifyou’remakingalargereductioninwheelcutandthisproceduredoesnotwork,youmayhavetoreplaceorinternallyresetthepoppetsusingtheproceduredescribedintheappropriategearservicemanual.
1. Settheaxlestopstovehiclemanufacturer’swheelcutorclearancespecifications.
2. Makesuretheengineisoffandtheroadwheelsareinstraightaheadposition.
3. Removeanddiscardthepoppetfixedstopboltandwasher(ifequipped)fromthelowerendofthehousingonboththemaingearandtherotarycylinder.Ifeitherunithasapoppetadjustingscrewandjamnutthatneedtobereplaced,removeanddiscardthematthispointalso.Ifanewpoppetadjustingscrewandnutarebeingused,turnthescrewsintothenon-sealingendofthejamnutsuntiltheAllendriveendofthescrewisflushwiththenut.
CAUTION
BesuretheAllendriveendofthescrewisnotbelowthefaceofthenut.Failingtokeepitflushwiththefaceofthenutwillcausethepoppetseatflangetobreaklateronduringthisprocedure.
4. Iftheadjustingscrewisalreadypartofthemaingearorrotarycylinder,backthenutoffoftheadjustingscrewuntilitisflushwiththeAllendriveendoftheadjustingscrew.
5. Turnthenewadjustingscrewandjamnut(withoutrotatingthejamnutonthescrew)intothehousinguntilthejamnutisfirmlyagainstthehousing,onboththemaingearandtherotarycylinder,usinganAllenwrench.Tightenthejamnutagainstthehousing.
6. Refillthesystemreservoirwithapprovedhydraulicfluid.
CAUTION
Donotmixfluidtypes.Mixingoftransmissionfluid,motoroil,orotherhydraulicfluidswillcausesealstodeterioratefaster.
7. Placeajackunderthecenterofthefrontaxleandraisethefrontendofthevehiclesothesteeraxletiresareofftheground.
8. Starttheengineandletitrunatidlespeed.
9. Notewhichoutputshafttimingmarkisnearestthehousingpistonbore.
10. Turnthesteeringwheelinthedirectionthatmakesthistimingmarkmovetowardtheadjustingscrewsyoujustinstalledonboththemaingearandtherotarycylinder.Turninthisdirectionuntilaxlestopcontactismade.
11. Pullhardonthesteeringwheel(put40lbs.rimpullona20”dia.steeringwheel)aftertheaxlestopiscontacted.
CAUTION
Donotholdthesteeringwheelatfullturnformorethan10secondsatatime;theheatbuild-upatpumpreliefpressuremaydamagesystemcomponents.
12. Turnthesteeringwheelintheoppositedirection(endoftimingmarkpointsawayfromadjustingscrew)untiltheotheraxlestopiscontacted.
13. Pullhardonthesteeringwheel.
17
14. Releasethesteeringwheelandshutofftheengine.
15. Loosenthejamnutandbackouttheadjustingscrewuntil1”ispastthenutonboththemaingearandtherotarycylinder.Tightenthejamnutagainstbothhousings.
16. Starttheengineandletitidle.
17. Turnthesteeringwheel,sothatthetimingmarkontheoutputshaftpointstowardtheadjustingscrew,untilaxlestopcontactismade.
18. Pullhardonthesteeringwheelandholditinthispositionfornomorethan10secondsatatime,thenreleasetoallowthesystemtocool.
19. Repeatthisholdandreleaseprocesswhilecompletingthefollowingsteps.Firstonthemaingear,thenontherotarycylinder.
NOTE
Pausetheturning-inprocesseachtimethedriverreleasesthesteeringwheel;continueturningtheadjustingscrewinonlywhilethewheelisheldatfullturn.
Main Gear Adjustment 1. Withsteeringwheelheldatfullturn,loosenthejamnutonthemaingear,andholditinplacewithawrenchsoitwillnot
contactthehousing.
2. Turntheadjustingscrewin(clockwise)usingfinger-pressureonly(donotusearatchet),untiltheAllenwrenchstops.Atthispoint,theadjustingscrewhascontactedthepoppetseat.Donotattempttoturnitinfarther.
3. Backofftheadjustingscrew31/4turnsandtightenthejamnut.Torquethejamnutto35ft•lbs.
Rotary Cylinder Adjustment 1. Withsteeringwheelheldatfullturn,loosenthejamnutontherotarycylinderandholditinplacewithawrenchsoitwill
notcontactthehousing.
2. Turntheadjustingscrewin(clockwise)usingfinger-pressureonly(donotusearatchet),untiltheAllenwrenchstops.Atthispoint,theadjustingscrewhascontactedthepoppetseat.Donotattempttoturnitinfarther.
3. Backofftheadjustingscrew31/4turnsandtightenthejamnut.Torquethejamnutto35ft•lbs.
4. Thepoppetsonboththemaingearandrotarycylinderhavenowbeenreset.Lowerthevehicle.Checkthefluidlevelinthereservoirandfillifrequired.
NOTE
Donotremovethepoppetadjustingscrews,theyarenowpartofthemaingearandrotarycylinderassemblies.NOTE
Thelengthofthepoppetadjustingscrewbeyondthenutmaybedifferentforeachvehicle,butmustbenomorethan11/16”forproperthreadengagement.
18
Air Bleeding the Steering System
Automatic Bleed Gears
1. Fillthereservoir.
2. Starttheengine,letitrunfor10seconds-withoutsteering,thenshutitoff.
3. Checkthereservoir,andrefillifthefluidlevelhasdropped.
4. Repeatatleastthreetimes,checkingandrefillingthereservoireachtimeifnecessary.
NOTE
Donotallowthefluidleveltodropsignificantlyorrunoutofthereservoir.Thismayinduceairintothesystem.
5. Starttheengineandletitidlefor2minutes-withoutsteering.Shutofftheengineandcheckthefluidlevelinthereservoir.Refillifrequired.
6. Starttheengineagain.Steerthevehiclefromfulllefttofullrightseveraltimes.Automaticbleedsystemsshouldnowbefreefromtrappedair.
7. Finally,besuretocheckthefluidlevelinthereservoir.Refillifnecessarybeforereturningthevehicletoservice.
Gear Mounting Configurations
Visual Identification
Whenyouairbleedasteeringsystem,youaresimplyallowingairtrappedinthecavitiesofthesteeringgeartoescape.Asageneralrule,ifyoursteeringgearisa“standardmount”,youshouldusetheAutomaticBleedmethod.Ifyourgearisan“invertedmount”,youwillneedtousetheManualBleedmethodtopurgethetrappedairfromthegear.
Auto Bleed Plug Location
Standard Inverted
Auto Bleed Plug Styles
Hex Head Torx Head
19
Manual Bleed Gears
1. Fillthereservoir.
2. Starttheengine,letitrunfor10seconds-withoutsteering,thenshutitoff.
3. Checkthereservoir,andrefillifthefluidlevelhasdropped.
4. Repeatthisprocessatleastthreetimes,checkingandrefillingthereser-voireachtimeifnecessary.
NOTE
Donotallowthefluidleveltodropsignificantlyorrunoutofthereservoir.Thismayinduceairintothesystem.
5. Starttheengineandletitidlefor2minutes-withoutsteering.Shutofftheengineandcheckthefluidlevelinthereservoir.Refillifrequired.
6. Starttheengineagain.Steerthevehiclefromfulllefttofullrightseveraltimes.
7. Again,checkthefluidlevelinthereservoir.
8. Withtheengineidling,steerfromfullleftturntofullrightturnseveraltimes.Stopsteeringwiththewheelspointedstraightaheadandloosenthemanualbleedscrew2-3turns.
9. Allowairandaeratedfluidto“bleedout”untilfluidappearswithoutbubbles.
10. Closethebleedscrew,refillthereservoirifrequired.
11. Repeatthisprocessthreeorfourtimesuntilalltheairisdischarged.Torquemanualbleedscrewto45in•lb.
CAUTION
Donotturnsteeringwheelwithbleedscrewloosened.
Figure 1
Manual Bleed Screw Location
Figure 1
Manual Bleed Screw Style
5/16” Hexagon Screw
20
Flushing the Steering System
Thesteeringsystemmustbeflushedeverytimeagear,pump,orreservoirgetsreplaced,regardlessifthecomponentsareneworareremanufactured.
1. Setparkingbrakeonvehicleandblockrearwheels.
2. Raisethefrontendofftheground.
3. Takevehicleoutofgearandputintoneutralposition.
4. Raisehoodandwipedownareaaroundthesteeringgearandthehydrauliclinesrelatedtothesteeringsystem.
5. Placeadrippanunderthesteeringgeartocatchtheoil.
6. Removeboththepressureandreturnlines(Figure1)fromthesteeringgearandallowtheoiltodrainintotheemptycontainer.
7. Removefilter(Figure2)fromthepowersteeringfluidreservoiranddiscard.Disconnectthesupplylinefromthereservoir.
8. Rinseandcleantheinsideofthereservoirwithanapprovedsolvent,thenairdry.Donotuseashopragtowipetheinsideofthereservoirandmakesurethatnoneofthesolvententerstherestofthesteeringsystem.Ifthereservoirismadefromplasticinspectforcracksanddamage.Replaceifnecessary.
9. Turnsteeringwheelfromfulllefttofullright3-4times.CollectthedrainedoilinthesamecontainerasinStep6.Thiswillpurgetheoilfromthesteeringgear.
10. Reconnectpressureandreturnlinestothesteeringgear.Connectthesupplylinetothereservoirandthentightenallfittings.
11. Installnewfilterelementintothereservoir.
12. Cleanreservoirfillercapwithanapprovedsolvent.Inspectgasketandreplaceifnecessary.
13. Inspectallhydraulichoses(Figure3)forcracks,softorsweatspotsandsignsoflocalcollapse(removeallcovers/corrugatedtubingfromhosestodothis)andreplaceanythatarefoundtobedefective.
14. Checkanyfittingsandconnectorsforblockage.Clearanyblockagesusinganappropriatemethod.
Figure 1
Figure 2
Figure 3
21
15. Fillreservoirwithapprovedreplacementfluidandreinstallthefillercap(Figure5).
16. Startenginefor10seconds,stop,andcheckreservoirfluidlevelandtopoffifnecessary.Youmayneedtorepeatthisprocedure3or4times.
17. Uponcompletionoffillingthereservoir,starttheengineandletitidle.Atengineidle,steerfullrightandfullleft(Figure6)onceandreturntostraightahead.Stopengineandcheckpowersteeringreservoirlevelandtopoffifrequired.
CAUTION
Donotholdsteeringwheelatfullturnforlongerthan10secondsasthiswillcausesystemtooverheat.
18. Restartengineandsteerfullturnseachdirection3or4times.
19. Stopengineandrecheckreservoirfluidlevelandadjusttocorrectlevel,ifneeded.
20. Inspectsystemforleaksandcorrectifnecessary.
21. Bleedairfromthesystem,ifrequired.
22. Removedrippanandlowervehicle.Removeblocksfromwheelsandreturnvehiclefornormalservice.
Figure 6
Figure 5
22
Power Steering System Analyzer (PSSA)Application and UseIntroductionThisbookletisintendedtogivetheyou,thetechnician,abetterunderstandingofthepowersteeringsystemanalyzer.Primarily,howitworksandhowtoproperlyuseittodiagnosehydraulicpowersteeringrelatedissues.YoushouldalsoknowthattheuseofthepowersteeringsystemanalyzerisrequiredwhencompletingmanyofthediagnostictestsfoundinourChartYourWaytoEasySteering-DiagnosticsServiceManual.ThetestproceduresweredevelopedusingTRWpowersteeringcomponents.However,theoperatingprinciplesofthepowersteeringsystemanalyzercanbeappliedtoallcommercialpowersteeringsystems.
Thegoalofthisbookletistotakeyoustep-by-stepthroughteachofthetestprocedureswhichrequiretheuseofthepowersteeringsystemanalyzer.ThiswillthenassistyouinlocatingtherootcauseofanyhydraulicsteeringrelatedcomplaintandprovideyouwithnecessarytestresultswhencallingTRW.
WARNING
Whileperformingthesetests,TRWadvisesthatyoutakenecessaryprecautionswhenworkingwithinternalvehiclecomponentsandhothydraulicfluid.Besuretotakespecialcaretoprotectyourself,andthosearoundyou,whileperformingadiagnostictest.
CAUTION
Donotattempttodiagnoseahydraulicsteeringrelatedproblemwithoutusingapowersteeringsystemanalyzer.Youwillnotbeabletoproperlydeterminethecorrectinformationneededtoanalyzeanddiagnosethesteeringsystem.
Thisbookletwillshowyouhowtoproperlyinstallthepowersteeringsystemanalyzerintothepowersteeringsystemanduseittogetmeasuredresultsforthefollowingtests;PowerSteeringPump,PumpFlowControlResponse,PoppetTripPressure,andInternalLeakage.
Besuretorecordyourresultsinthetables(Page6)andbepreparedtoprovidethisinformationwhencallingtotalkwithyourTRWTechnicalServiceRepresentatives.
Installing the Power Steering System Analyzer
SomeChartYourWaydiagnostictestproceduresrequireapowersteeringsystemanalyzerwhichisacombinationflowmeter,pressuregaugeandloadvalveallinone.Thesystemanalyzerletsyoumeasureflowandpressureandapplyaloadtothepumpthroughthesteeringsystemshydrauliclines.Dependingonthemodelofgaugebeingused,youmayseeanarrowshowingthedirectionoftheoilflow.Thiswillassistyouinmakingsuretheflowmeterisproperlyinstalledinthesystem.Aloadvalve,locatednearthegauge,isusedtoeitherrestrictoropentheflowofoiltothesystem.
ThegaugehasaSAE/MetricscaletoreadtheflowofoilineitherGPM(U.S.gallonsperminute)orLPM(litersperminute).ThesystempressureismeasuredineitherPSI(U.S.poundspersquareinch)orkg/cm2(kilogramspercentimetersquared).
Thepowersteeringsystemanalyzerisinstalledbetweenthepowersteeringpumpandthesteeringgear.Connectthevalveendofthepowersteeringsystemanalyzertothesteeringgear’spressureportandtheotherendtothepump’spressureport.
23
Power Steering Pump Test
Thissectionwillinstructyouonhowtomeasurepumpflowandsystempressure.Besuretofollowthelinestomakesurethattheyarehookedupcorrectlybeforeattemptingtoperformanytests.
Verifyengineidlespeedperoriginalequipmentmanufacturersspecifications.
1. Installthepowersteeringsystemanalyzerinthepressurelinewithloadvalvefullyopen.Recheckandadjustthefluidlevel,ifrequired.Installatemperaturegaugeinthereservoirandbeginthetestwiththefluidtemperaturebetween125-135°F(52-57°C).
2. Runtheengineatidle.Measureandrecordtheflowandpressurereadings(TableA).
CAUTION
Whenclosingthepowersteeringsystemanalyzerloadvalve,dososlowlyandkeepaneyeonthepressuregauge.Donotallowthesystemtoexceed3000psior(207bar)forsafetyofpersonnelandtopreventdamagetothevehicle.
CAUTION
Donotkeeptheloadvalveclosedformorethan5secondsatatimebecausedamagetothesystemmayresultfromexcessiveheatbuild-up.
3.Withtheengineatidel,adjusttheloadvalvetoshow1000PSIonthegauge.Measureandrecordtheflowandpressurereadings(TableA).
4. Nowwiththeloadvalvefullyopen,increasetheenginespeedto1500RPM,measureandrecordtheflowandpressurereadings(TableA).
5. Withtheenginespeedat1500RPM,adjusttheloadvalvetoshow1000PSIonthegauge.Measureandrecordtheflowandpressurereadings(TableA).
6. DeterminetherecommendedflowrangeandmaximumallowablesystempressureforthesteeringsystembeingusedbyreferringtoyourOriginalEquipmentManufacturer’sservicemanualforyourapplication.
7. Comparetheminimumandmaximumflows,andthereliefpressureyoumeasured,togearandpumpspecificationsasshowninyourservicemanuals
8. Iftheminimummeasuredpumpflowislessthantheminimumrecommendedflowforthesteeringgearused;thepumpmaynotbeputtingoutenoughflowforanadequatesteeringspeed.Ifthemaximumsystempressureislowerthanthatspecifiedforthepump,itmaynotbedevelopingenoughpressuretosteerthevehicle.Ifeithercaseexists,thepumpmayneedtoberepairedorreplaced.
NOTE
Whenhydraulictestsarecompletedandhosesarereconnected,checkthefluidlevelandbleedtheairfromthehydraulicsystemusingtheproceduresoutlinedintheappropriatesteeringgearservicemanual.
24
Pump Flow Control Response Test
Thissectionwillinstructyouonhowtodetermineproperpumpflowcontrolresponse.Besuretofollowthelinestomakesurethattheyarehookedupcorrectlybeforeattemptingtoperformanytests.
1.Installthepowersteeringsystemanalyzerinthepressurelinewithloadvalvefullyopen.Recheckandadjustthefluidlevel,ifrequired.Installatemperaturegaugeinthereservoirandbeginthetestwiththefluidtemperaturebetween125-135°F(52-57°C).
CAUTION
Ifthesystemtemperaturegoesover250°F(121°C),or150°F(66°C)abovethesurroundingtemperatureatanytimeduringthetest,stopthetest.Thistemperaturelevelisconsideredextremeandsteeringsystemperformanceandlifewillbeseriouslyaffected.Damagetohoses,seals,andothercomponentsmayresultifoperatedatextremetemperature.Ifthesteeringsystemisoperatingabovetherecommendedtemperatures,theheatproblemmaybetherootcauseofthecomplaint.
CAUTION
Whenclosingthepowersteeringsystemanalyzerloadvalve,dososlowlyandkeepaneyeonthepressuregauge.Donotallowthesystemtoexceed3000psior(207bar)forsafetyofpersonnelandtopreventdamagetothevehicle.
CAUTION
Donotkeeptheloadvalveclosedformorethan5secondsatatimebecausedamagetothesystemmayresultfromexcessiveheatbuild-up.
2. Withtheengineatidle,notetheflowrate.Fullyclosetheloadvalveuntiltheflowdropstozero.Quicklyopentheloadvalveobservingtheflowmeter.Theflowratemustinstantlyreturntothereadingyouhavealreadynoted.
3. Withtheloadvalveopenruntheengineto1500RPMandnotetheflowrate.Fullyclosetheloadvalveuntiltheflowdropstozero.Quicklyopentheloadvalveobservingtheflowmeter.Theflowratemustinstantlyreturntothereadingyouhavealreadynoted.
4. Conductthispumpresponsetestthreetimesatidleandthreetimesat1500RPM.Recordyourresults(TableB).Iftheflowratedoesnotreturnimmediately,thepumpismalfunctioning,whichcanresultinamomentarylossofpowerassist.
NOTE
Whenhydraulictestsarecompletedandhosesarereconnected,checkthefluidlevelandbleedtheairfromthehydraulicsystemusingtheproceduresoutlinedintheappropriatesteeringgearservicemanual.
25
Poppet Trip Pressure Test
Thissectionwillinstructyouonhowtoverifypoppettrippressure.Besuretofollowthelinestomakesurethattheyarehookedupcorrectlybeforeattemptingtoperformanytests.
1. Installthepowersteeringsystemanalyzerinthepressurelinewithloadvalvefullyopen.Recheckandadjustthefluidlevel,ifrequired.Installatemperaturegaugeinthereservoirandbeginthetestwiththefluidtemperaturebetween125-135°F(52-57°C).
2. Increaseenginespeedto1500RPM.
3. Steerthevehicleintoafullrightturn.Then,recordthepoppettrippressure(TableC)shownonthepowersteeringsystemanalyzerpressuregauge.
4. Now,steerthevehicleintoafullleftturn,andagain,recordthepoppettrippressure(TableC)shownonthepowersteeringsystemanalyzerpressuregauge.
Eachrecordedvalueshouldbeatleast200-400PSIbelowpumprelieftestvaluepreviouslynotedinTableA.Ifyoudonotmeetthiscriteria,poppetsshouldbereset,usingtheprocedureoutlinedintheappropriatesteeringgearmanual.Whencomplete,makesuretorecheckthevehicletomakesureitisoperatingproperly.
NOTE
Whenhydraulictestsarecompletedandhosesarereconnected,checkthefluidlevelandbleedtheairfromthehydraulicsystemusingtheproceduresoutlinedintheappropriatesteeringgearservicemanual.
Internal Leakage Test
Finally,youwillbeinstructedonhowtomeasureinternalleakageforbothasinglegearanddualgearsystem.Besuretofollowthelinestomakesurethattheyarehookedupcorrectlybeforeattemptingperformanytests.
WARNING
Thistestcanbedangerousifnotperformedcorrectly.Keepyourfingersclearoftheaxlestopsandspacerblockduringthistest.Makesurethatthespacerblockcontactstheaxlestopsquarely.Contactthatisnotsquarecouldbreaktheaxlestopsordangerouslythroworejectthespacerblock.
1. Installthepowersteeringsystemanalyzerinthepressurelinewithloadvalvefullyopen.Recheckandadjustthefluidlevel,ifrequired.Installatemperaturegaugeinthereservoirandbeginthetestwiththefluidtemperaturebetween125-135°F(52-57°C).
2. Totestthesteeringgearforinternalleakage,youmustfirstpreventoperationofthegear’sinternalunloading(poppet)valvesorreliefvalve(orboth,insomegears).Thiswillallowfullpumpreliefpressuretodevelop.Topreventoperationofthepoppets,placeanunhardenedsteelspacerblock,atleastoneinchthickandlongenoughtokeepyourfingersclear,betweentheaxlestopatonewheel.Ifthesteeringgearisequippedwithareliefvalve,removethereliefvalvecap,o-ring,andtwopiecereliefvalvefromthesteeringgearvalvehousing.Installthereliefvalveplug,specialtoolnumberJ37130,initsplacetopreventoperationofthesteeringgearreliefvalve.
NOTE
Besureyoureinstallthereliefvalveandvalvecapwithnewo-ring,backintothegearafterthistest.
26
CAUTION
Whenrunningthistest,donotholdthesteeringwheelinthefullturnpositionforlongerthan5to10secondsatatimetoavoiddamagingthepump.3. Turnthesteeringwheeluntiltheaxlestopsbottomonthespacerblock.
4. Apply20poundsofforcetotherimofthesteeringwheelduringthistesttobesurethatthesteeringgearcontrolvalveisfullyclosed.Thepressuregaugeshouldnowreadpumpreliefpressure(seeTableA).Recordthesteeringgearinternalleakage(TableD)ontheflowmeter.
5. Repeatthistestfortheoppositedirectionofturn.
6. Ifinternalleakageisgreaterthan1gallonperminute(3.8litersperminute)andthereisnoauxiliaryhydrauliclinearorrotarycylinderinthesystem,repairorreplacethegear.
Iftheinternalleakageisgreaterthan2gallonsperminute(7.6litersperminute),andthereisanauxiliaryhydrauliclinearorhydraulicrotarycylinderinthesystem,controlledbythegear,isolatetheauxiliarycylinderfromthesystembydisconnectingtheauxiliarycylinderhydrauliclinesatthesteeringgearauxiliaryports.Plugthesteeringgearportswithsuitablesteelorhighpressureplugsorcaps.
Intheeventthatarotarycylinderisusedinthesystem,connectthedisconnectedlinestogetherwithasuitableunionfitting.Inthecaseofalinearcylinder,firstplugthedisconnectedlinesandthendisconnectthecylinderfromsteeringlinkage,makingsureitwillclearthesteeredaxle
RepeattheinternalleakagetestandrecordyourresultsinTableD.Iftheinternalleakageislessthan1gallonperminute(3.8litersperminute),repairorreplacetheauxiliarycylinder.Iftheinternalleakageisgreaterthan1gallonperminute(3.8litersperminute),repairorreplacethegear.
NOTE
Whenhydraulictestsarecompletedandhosesarereconnected,checkthefluidlevelandbleedtheairfromthehydraulicsystemusingtheproceduresoutlinedintheappropriatesteeringgearservicemanual.
27
Test Results
Table A
Table B
Table C
Table D
Single Gear System Dual Gear System
GPM or LPM at: Engine (RPM) No Load 1000 PSIIdle1500
Relief Pressure_________PSI/BAR
PSI or BAR
Pump Relief #1 (Idle)
Pump Relief #2 (Idle)
Pump Relief #3 (Idle)
PSI or BAR
Pump Relief #1 (1500 RPM)
Pump Relief #2 (1500 RPM)
Pump Relief #3 (1500 RPM)
PSI or BAR
Full right hand turn
Full left hand turn
GPM or LPM
Full right hand turn
Full left hand turn
GPM or LPM
Full right hand turn
Full left hand turn
28
1
2
5
3
6
8
4
7
1
2
5
11
10
9
3
6
8
4
7
1
2
1413
12
5
11
10
9
3
6
8
4
7
1
2
1413
12
5
11
10
9
3
6
8
4
7
PSSA Installations
Typical Steering System Single Gear System
Dual System Single Gear, Linear Cylinder Assist
Dual System Single Gear, Rotary Cylinder
Legend
1. Thermometer 5. SteeringGear 9. LoadValve 13. AuxilliaryLine2. SupplyLine 6. ReturnLine 10.FlowMeter 14.AssistCylinder3. Pump 7. ReservoirFilter 11. PressureGauge LinearorRotary4. PressureLine 8. Reservoir 12. AuxilliaryLine
29
Inspection Criteria
Firstbylightlyrockingthesteeringwheel,observeanyloosenessinthetwomatingtapers,oranymovementofthestudnut.Loosenessineitherplacerequiresfurtherinspection.
Ifeitherofthematingtaperedpartsshowdistortionorwear,bothpartsmustbereplaced.
Second,makesurethewheelsarestraightahead,thetruckengineisturnedoff,andnoforceisbeingexertedonthelinkagebythesteeringgear.Tocheckthesoundnessofthejoint,justuseyourhandtopushandpullthetierodendinandoutinthedirectionoftheballstudaxis(seeillustration).
Forinspectionpurposes,thelinkmustbeheldwithouttwisting,andwithhand-pressureonly(approximately100lbs),measuredwithascaleforinandoutmotionontheballstudaxis.Iftheinandoutmotiononthestud’saxismeasuresover1/8”or3mmwithhandpressureonly,thenthevehicleshouldbetakenoutofservice.
Ifitmoves,butmeasureslessthan1/8”(3mm)itshouldbereplacedatthenearestpracticalservicecenter.Anymovementlessthan1/8”(3mm)isstrictlyamaintenanceissueforthevehicle.
Donotuseawrenchorotherobjecttoobtainmoreleverage.Applyingleveragetoanylinkagecancausemovementregardlessofwhetherornotthelinkageneedstobereplaced.Applyingleveragecanalsodamagethelinkage
Don’tapplysteeringgearpowertothejointtotestforaworntierodend;thatproducesnormalmovement,andthatmovementisnotanindicatorofwear.
Maintenance Checklist
Eachtimethetierodendsarelubricatedyoushouldalsovisuallyinspectfor:
• Cracks,breaksorbendsinthelinkagecomponents.
• Checkforbrokenclampsandgougesontubesfromrubbingparts.
• Checkformissingordamagedgreasefittings.Sometierodendsarenotequippedwithgreasefittingsfromthefactory.Butifoneissupposedtobethereanditisnot,themissingfittingmustbereplaced.
• Checkforanyformoftearingorimpropersealingontheseal.Alsocheckforwearonthesocketthroat.
• Checkalltierodendconnectionsformissingcotterpins.
Linkage Inspection, Maintenance,Replacement, and Adjustment
Inspect for movement alongvertical axis only.
Tie Rod End - Section View
30
Figure 2
Figure 1
Figure 3
Figure 4
Tie Rod End Replacement
Ifthelashisoriginatingfromthetierodend,itwillneedtobereplaced.Ifthelashisinthetaperedstudconnectionbetweenthetierodendanditsmatingpart,boththetierodendandthematingpartmustbereplacedtorecreateaproperfitbetweenthetwo.
1. Loosentheclamporjamnutonthetierodend(Figure1).
2. Disconnectthetierodendfromthematingcomponent.
3. Unscrewthetierodendfromthetube(Figure2).Useapipewrenchifnecessary,beingcarefulnottodeformthetube.
4. Screwthenewtierodendintothetube(Figure3).Tierodendthreadsmustbevisibletheentirelengthofthecrosstubeslot.Thetierodendistobeengagedatleastonethreaddeeperthantheendofthecrosstubeslot.
5. Refertotheadjustmentandcenteringprocedures,forthetypeofassemblyyourareworkingon,coveredinthisdocument.
6. Torquetheclampnutorjamnut(Figure5)tothevehiclemanufacturer’sspecifications.
Figure 5
31
Figure 2
Figure 1
Figure 3
Figure 4
Figure 5
Draglink– One End Adjustable
1. Positiontheroadwheelsstraightahead.
2. Disconnectthedraglinkatthepitmanarmusingtheappropriatetool.
3. Makesurethesteeringgearisoncenterbyaligningthetimingmarksonthehousingandoutputshaft.
4. Loosentheclamponthedraglink.
5. Adjustthedraglinklengthtofittheholesonthepitmanarmandtheaxlesteerarm.
6. Graspthelongsideofthedraglinkwithbothhands(Figure1).Rotateitawayfromyouasfarasitwillgo,thentowardyouasfarasitwillgo.Centerbetweenthesetwopoints.
7. Holdthelongsideinplace.Graspthetierodend(Figure2)androtateittowardyouandawayfromyouasfarasyou.Centerthetierodendbetweenthesetwopoints.
8. Withbothendscentered,tightentheclamp,andtorque(Figure3)tovehiclemanufacturer’sspecifications.
WARNING Iftheclampistack-welded(Figure4),don’tremovethetackweld.Ifremoved,clampingforcewillnotbeenoughtokeepthetierodendthreadsstationary.Lossofsteeringcontrolwillresult.Ifthetackweldedendrequiresreplacement,theentireassemblyneedstobereplaced.
NOTE Iftheclampisfree-to-rotate(Figure5)itcanbetightenedinanypositionproperly,aslongasthereisenoughclearancefromotherparts.
9. Lubricatebothtierodends(unlesstheyarenon-greaseableends)untilyoucanseecleangreasepurgingoutoftheseal.Use#2NLGIGrease.
NOTE Ahandoperatedgreasegunmustbeusedwhenlubricatinglinkage.Powergreasegunsgenerateexcessiveforcethatwilldamagethebootseal.
NOTE Thispurgeisnecessarytoensurecontaminantsareremovedfromsocketassemblies.
32
Draglink– Two End Adjustable
1. Positiontheroadwheelsstraightahead.
2. Loosentheclampsonthebothendsofthedraglink.
3. Rotatethecentertubeofthedraglink(Figure1)untilthesteeringgearisoncenter(housingandoutputshafttimingmarksaligned).
4. Tightentheclampsandtorque(Figure2)tomanufacturer’sspecifications.
WARNING Iftheclampistack-welded(Figure3),don’tremovethetackweld.Ifremoved,clampingforcewillnotbeenoughtokeepthetierodendthreadsstationary.Lossofsteeringcontrolwillresult.Ifthetackweldedendrequiresreplacement,theentireassemblyneedstobereplaced.
NOTE Iftheclampisfree-to-rotate(Figure4)itcanbetightenedinanypositionproperly,aslongasthereisenoughclearancefromotherparts.
5. Lubricatebothtierodends(unlesstheyarenon-greaseableends)untilyoucanseecleangreasepurgingoutoftheseal.Use#2NLGIGrease.
NOTE Ahandoperatedgreasegunmustbeusedwhenlubricatinglinkage.Powergreasegunsgenerateexcessiveforcethatwilldamagethebootseal.
NOTE Thispurgeisnecessarytoensurecontaminantsareremovedfromsocketassemblies.
Figure 2
Figure 1
Figure 3
Figure 4
33
Tie Rod Tube Assembly– One End Adjustable
1. Positiontheroadwheelsstraightahead.
2. Raisethefrontendofthevehiclesothesteeraxletiresareofftheground.
3. Loosentheclamponthetierodtube.
4. Turnthehexadjusteruntilthetoeiscorrect.
WARNING Donotadjustthetierodendtoapositionwhereyoucanseetheendofthetierodendthreadsthroughtheslotinthetube.Ifthesocketthreadedendisvisible,corrosionmayoccurinthetubeandweakenthecomponents.
5. Graspthelongsideofthetierodwithbothhands(Figure1).Rotateitawayfromyouasfarasitwillgo,thentowardyouasfarasitwillgo.Centerthetierodbetweenthesetwopoints.
6. Holdthelongsideinplace.Graspthetierodend(Figure2)androtateittowardyouandawayfromyouasfarasyoucan.Centerthetierodendbetweenthesetwopoints.
7. Withbothendscentered,tightentheclamp,andtorque(Figure3)tovehiclemanufacturer’sspecifications.
WARNING Iftheclampistack-welded(Figure4),don’tremovethetackweld.Ifremoved,clampingforcewillnotbeenoughtokeepthetierodendthreadsstationary.Lossofsteeringcontrolwillresult.Ifthetackweldedendrequiresreplacement,theentireassemblyneedstobereplaced.
NOTE Iftheclampisfree-to-rotate(Figure5)itcanbetightenedinanypositionproperly,aslongasthereisenoughclearancefromotherparts.
9. Lubricatebothtierodends(unlesstheyarenon-greaseableends)untilyoucanseecleangreasepurgingoutoftheseal.Use#2NLGIGrease.
NOTE Ahandoperatedgreasegunmustbeusedwhenlubricatinglinkage.Powergreasegunsgenerateexcessiveforcethatwilldamagethebootseal.
NOTE Thispurgeisnecessarytoensurecontaminantsareremovedfromsocketassemblies.
Figure 2
Figure 1
Figure 3
Figure 4
Figure 5
34
Tie Rod Tube Assembly– Two End Adjustable
1. Positionroadwheelsstraightahead.
2. Loosentheclampsonbothendsofthetierodtube.
3. Rotatethecentertubeofthetierod(Figure1)untilachievepropertoe-inmeasurementsonthefrontwheels.
4. Tightentheclampsandtorque(Figure2)tomanufacturer’sspecifications.
WARNING Iftheclampistack-welded(Figure3),don’tremovethetackweld.Ifremoved,clampingforcewillnotbeenoughtokeepthetierodendthreadsstationary.Lossofsteeringcontrolwillresult.Ifthetackweldedendrequiresreplacement,theentireassemblyneedstobereplaced.
NOTE Iftheclampisfree-to-rotate(Figure4)itcanbetightenedinanypositionproperly,aslongasthereisenoughclearancefromotherparts.
9. Lubricatebothtierodends(unlesstheyarenon-greaseableends)untilyoucanseecleangreasepurgingoutoftheseal.Use#2NLGIGrease.
NOTE Ahandoperatedgreasegunmustbeusedwhenlubricatinglinkage.Powergreasegunsgenerateexcessiveforcethatwilldamagethebootseal.
NOTE Thispurgeisnecessarytoensurecontaminantsareremovedfromsocketassemblies.
Figure 1
Figure 2
Figure 3
Figure 4
35
Figure 1
Drop Center Tie Rod Tube Assembly– One End Adjustable
1. Positionroadwheelsstraightahead.
2. Placeajackunderthecenterofthefrontaxle.Raiseupthefrontendofthevehiclesothesteeraxletiresareofftheground.
3. Loosentheclamponthetierodtube.Disconnectthetierodfromthetierodarmattheadjustableend.
4. Adjustthesocketinone-full-turnincrements(Figure1).Reinstallthesocketend,tighten(donottorque)thefasteneraftereachfullturn.
5. Checkthetoe-inmeasurementaftereachfullturnadjustment.Repeatasnecessaryuntilthetoeiscorrect.
6. Graspthelongsideofthetierodwithbothhands(Figure2).Rotateitawayfromyouasfarasitwillgo,thentowardyouasfarasitwillgo.Centerthetierodbetweenthesetwopoints.
7. Holdthelongsideinplace.Graspthetierodend(Figure3)androtateittowardyouandawayfromyouasfarasyoucan.Centerthetierodendbetweenthesetwopoints.
8. Withbothendscentered,tightentheclamp,andtorquetovehiclemanufacturer’sspecifications.
WARNING Iftheclampistack-welded(Figure4),don’tremovethetackweld.Ifremoved,clampingforcewillnotbeenoughtokeepthetierodendthreadsstationary.Lossofsteeringcontrolwillresult.Ifthetackweldedendrequiresreplacement,theentireassemblyneedstobereplaced.
NOTE Iftheclampisfree-to-rotate(Figure5)itcanbetightenedinanypositionproperly,aslongasthereisenoughclearancefromotherparts.
9. Lubricatebothtierodends(unlesstheyarenon-greaseableends)untilyoucanseecleangreasepurgingoutoftheseal.Use#2NLGIGrease.
NOTE Ahandoperatedgreasegunmustbeusedwhenlubricatinglinkage.Powergreasegunsgenerateexcessiveforcethatwilldamagethebootseal.
NOTE Thispurgeisnecessarytoensurecontaminantsareremovedfromsocketassemblies.
Figure 2
Figure 4
Figure 5
Figure 3
36
TRW AutomotiveCommercial Steering Systems800 Heath StreetLafayette, IN 47904Tel 765.423.5377Fax 765.429.1868www.trucksteering.com© TRW Inc. 2008 TRW800 Rev. 4/08