pedal box construction guide 02

Haynes

Alternative and Low-CostPedal-Box

Construction Guide

Version 2.012th June 2012By Sylvain [email protected]

See pictures of my Pedal-Box construction on my blog:http://vouchtroadster.blogspot.se/2012/05/pedalier1-pedal-box1.htmlhttp://vouchtroadster.blogspot.se/2012/06/pedalier2-pedal-box2.html

All 1:1 scaled drawing available in PDF and SVG formats on request at: [email protected]

Important note about the language

I’m French and not natural English speaking. I did my best to write this guide in the best English I could, but I’m aware it should be full of mistakes. I want to apology for that, and I hope it is under-standable enough.If anybody wants to help me to put this guide in a better English, I can send all the texts by email for correction, and integrate them in a new version.

Thank you.

Sylvain


Straight Pedal Shafts

The main goal of re-designing the Pedal-Box of the Haynes Roadster, as an alternative of the book’s Pedal-Box, was to use leftovers of tubes from the chassis building. Making the Pedal-Box is, according to the book, the last stage of the chassis builing. A that stage, the workshop is full of 25mm square section tubes bits, as well as 19mm (20mm in my case) round section tubes if you made the back panel as in the book.

The book’s pedals shafts could be cut by hand, but I guess with a very poor result, so it looks like most of the builders choose to order them laser cut, which is an extra cost I wanted to avoid. Same problem with the pivot tubes: according to the book, they should be 28mm diameter with 3mm walls, and this dimen-sion is not used anywhere else in the car. If you don’t have any scrap of that, it is a shame to buy a full length of tube for cutting only 3 x 30mm long pieces. So the idea was to make the pedal shafts from 25mm square section tubes, and the pivot tubes from 20mm round section tubes, in order to keep the cost of the Pedal-Box as low as possible.

Making the pedal shafts from straight tubes rather than from 3 and 5mm plates implies that you can not chose the shape: the pedal shafts will be straight. This gives a “single-seater” Pedal-Box’s look (without the brake bias balance bar for dual master-cyl-inder use though, but the brake pedal could be easily adapted to use one if you wanted). This “single-seater like” Pedal-Box is also very well adapted to the driver’s position in the Roadster, which is closer to a single-seater than to a saloon car.

Of course, I started the design from the book’s Pedal-Box, and I tried to keep the new one as close as possible to the original one. This alternative Pedal-Box is just an adaptation of the book’s Pedal-Box to straight shaft pedals, and not a completely new design that would have required engineer-ing skills I don’t have. So I respected pedal ratios, pivot point heights, lengths, and so on.

IntroductionBefore starting the construction, it might be important to know why and how I re-drew the Pedal-Box, and what technical choices I had to do and why. Here are some explanations about this alternative design.


First because I realized that the stoke of the clutch pedal would be shorter with the straight shaft than with the book’s pedal, I decided to make brackets that will allow to get a longer stroke if needed.

This was achieved by moving the pivot point forward, but keeping the original pivot point as well: the hole the closest to the back plate keeps the same pivot point as the book’s Pedal-Box, and the hole the further to the front keeps the position of the books pedal foot pad when leaning 20° forward, in order to keep at least the same max. stroke. The distance between these 2 holes is 26mm, so in between I had room to add an intermediate hole which gives an extra set-up option.

The stroke was not an issue for the brake and accelerator pedals, but I kept the same hole pattern for the 3 pairs of brackets. The result is a fully adjustable Pedal-Box: you can find the ideal pedal positions combination that suits your driving style or needs.

Straight shaft clutch pedal max. stroke

Book’s clutch pedal max. stroke

Book’s clutch pedal in normal position

Straight shaft clutch pedal in normal position


Clevis and Cable attach points

The other adaptation I had to do concerns the attach points of clevis and cables on the pedal shafts. A « plate » pedal just needs a hole in it to fit cables/clevis with a short bolt, but a with tubular pedal, it is different. As the attach point is inside the tube, we will need to remove part of the back face of the tube to allow the cables/clevis to move freely when the pedal moves.

Top-hat bushes

The book says to use a 30mm long pivot tube with a simple cylindrical bush inside, which makes the edges of the steel tube being in direct contact with the steel brackets. It doesn’t sound the best to me, so I opted for top-hat bushes (bushes with flange), in order to get a soft and sliding material between the tube and the brackets. For my built, I didn’t find bushes of the right dimension (except at a very prohibitive price!), and I had to make them myself, cutting, drilling and carving them into a PTFE rod. But if you have the right sources, you can find the right bushes (I know some nylon ones exists with these dimensions) this will be time saving for sure... and nicer result!

Forward Stops

The other elements I haven’t kept are the forward stop plates of the book’s Pedal-Box. I don’t find them particularly nice... So, having a 25mm wide face in the front of each pedal shaft, I thought I could just weld an M6 nut on it, in order to use an M6 bolt and a lock-nut as forward stops. I’m quite happy with the result as it does not only stop the pedals from moving forward, but it also allows to adjust the angle of the pedal quite accurately. Also, for the brake pedal, it avoids to drill another hole in the Roadster’s floor as the books says to do.


R=10.5

R=10.5

25

20

410

41

Diam 8

Diam 20

35 31

25 25

238

150

84

View A

View A

6

1031

21

BRAKE

234

Remove

137

97.8

BRAKE

Weld with 1mm gap

M6 nut M6 nut

Round section Diam 20 x 2 wall tubeL=25mm

100

50

Ang

le =

45°

BRAKE AND CLUTCH PEDAL PAD

Flat Bent

117

35

Ang

le =

53°

ACCELERATOR PEDAL PAD

Flat Bent

R=12.5

R=12.5

Curve Radius =127

Curve Radius =127


234

150

6

25 25

View A

84

View A

R=10,5

21

48

10

38

20

Diam 20

24

Diam 6

10

CLUTCH

20

CLUTCH

137

97.8

Weld with 1mm gap

M6 nut M6 nut


234

150

6

25 25

View A

84

View A

R=10,5

21

69

14

55

20

Diam 20

29

Diam 8

10

ACCELERATOR ACCELERATOR

101.8

13320

Weld with 1mm gap

M6 nut M6 nut



Brake Pedal Equipment

2mm

12mm

20mm

8mm

16mm

Padal Top Hat Bush Dimensions

Front Stop Bolt

Welded M6 nut

M6 Lock-Nut

M6 x 35 Bolt

Clevis Assembly

M8 x 40 bolt(25mm non-threaded) M8 Nylock Nut

M8 Washers

Clevis(8mm diam Axis)

Clutch Pedal Equipment

2mm

12mm

20mm

8mm

16mm


Front Stop Bolt

Welded M6 nut

M6 Lock-Nut

M6 x 35 Bolt

Clutch Cable Bolt Assembly(To Fit Ford Capri Clutch Cable)


M6 Washers

Accelerator Pedal Equipment

2mm

12mm

20mm

8mm

16mm


Front Stop Bolt

Welded M6 nut

M6 Lock-Nut

M6 x 35 Bolt

Clevis Assembly(the throttle cable will have t be adapted to the clevis)


M8 Washers

Clevis(8mm diam Axis)


Ford Sierra master-cylinder only(diam 41mm)

29 70 70 70 29

134

268

49 170 49

150

125

90

2030

Diam.16 Diam.16

Diam.8Diam.8

Diam.8Diam.8Diam.8Diam.8

Push-rod axis

BACK PLATE

250

29If CP16 is 3mm thick

27If CP16 is 1mm thick

25022

Diam.8 Diam.8 Diam.8Diam.8

250

50

40 55 60 55 40

PLATE H1

PLATE V1

PLATE H2


105

69

23

19

R=15R=15

13 13

15

Diam 8

R=15R=15

13 13

15

Diam 8

114

88

21

21

R=15

13 13

15

Diam 8

30

80

CLUTCH PEDAL BRACKET

ACCELERATOR PEDAL BRACKET

BRAKE PEDAL BRACKET

49 85 85 49

9 9

Distance between 2 brackets will depend of the thickness of the bushes flange. On my pedal box, this distance was 31mm (25mm pedal + 2x3mm flanges)

PlateH1

PlateH2

PlateV1

60

18

81


Diam.8 Diam.8 Diam.8Diam.8

49 85 85 49

9 9

7177

84

Plate H1(27 or 29)

Plate V1

Plate H2

Back Plate

20

16

20

16

Round section Diam 20 x 2 wall tube

27 or 29 53

25

70°

25

18

60

81

71 13 13

13 1377

84 13 13

Plate H2

Plate V1

Plate H1

Back Plate

Round section Diam 20 x 2 wall tube

M8 x 60 Bolts(completely threaded)

M8 Nuts

M8 Washers

Rear Stop Bolts Installation

Clutch Pedal Installation

M8 x 50 Bolts(35mm non-threaded)

M8 Washers M8 Nylock Nut

Accelerator Pedal Installation

M8 x 50 Bolts(35mm non-threaded)

M8 Washers

M8 Nylock Nut

Brake Pedal Installation

M8 x 50 Bolts(35mm non-threaded)M8 WashersM8 Nylock Nut

This work is licensed under the Creative Commons Attribution-Non-Commercial-ShareAlike 3.0 France License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/fr/ or send a letter to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA.

For any information regarding this work, please send me an email:[email protected]

Plan for your brake lines now!

Visit my website:http://sites.google.com/site/hydraulicforkitcars/

pedal box construction guide 02

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