Brake Pedal Arm Thickness

Hey everybody. Probably a dumb question, but I couldn't find an answer anywhere.

I'm fabricating a firewall mounted brake/clutch pedal setup for my '51 Chevy. Manual clutch with z/bar setup, power brakes.

I'm drawing the from Walton's kit for inspiration, like this one:



I'll be using 1/4" for the brackets, but what should I use for the pedal arms? Is 1/4" steel sufficient? Should I double it up? 1/2"? 3/8?

What about the width of the pedal?

Any suggestions?

 

I would go 5/8" on the brake arm and grind the edges down abit to give a squared oval look like a early factory arm...thicker is better. I would run a factory screw or bolt on pedal/pad combo, something vintage/stock appearing.

 

I agree pretty much with 111harv 1/2" would work just fine. Look in the local bone yard, they should have some that you can modify. I am doing a set of early 60's C=10 truck petals for my 39 Ford next week. Make sure the petal pads are at a comfortable angle. You can notch the arms and weld to get them where you want them.

 

The Walton one is a perfectly made, precise, exact fit. No fitting, grinding, filing, cutting, or welding. Just put it in. I work in a fab shop, and even we just by them from Walton. I'm not saying don't do it. It will be hard to match the engineering, quality, precision, and price. The Walton pedal arms are 3/8".

 

Get a swing pedal out of an 80's or 90's GM pickup at the junk yard. They are easy to adapt and use a plunger type brake light switch. They vary in pedal location and size depending on the transmission ( manual vs auto) .

 

I've always fabricated mine in 3/8" but its all about the way its designed, I've seen certain designs in 1/4" that have worked excellently.

 

You should ask an engineer friend or revert to Machinery Handbook, to me 1/2" thickness is overkill . But that's that's not a bad thing. Have you had a look at any stock pedal applications. I believe the jeep pedal assembly I had was 1/4" thickness

 

Some stock pedals are 1/8" but they have been designed to use that thickness in mind.

 

Its a matter of design, more than thickness.

 

I just installed another set of 60-62 Chevy truck pedals with the underdash brace, into another 32 last week. Nice fit and ties the dash, firewall, column, and pedals together rock solid. These are hyd clutch setup

The 63-66 truck made one simple change on the working end of the clutch cross shaft, to make the rod push straight down through the floor for a mechanical clutch with a z-bar or bell crank.

 

I'd totally go with the waltons setup except that it doesn't have a provision for the clutch - so I'm going to copy the design. I took a look at my dd and it's a 1/2" pedal shaft. I think I have enough raw material here to do it for the cost of time and consumables, so I'm going to give 'er a go. I'll do a thread on it.

I'd love to see any other firewall mounted brake/clutch designs. I've been looking around and there are a few good ideas. Show me

 

Have you looked at welderseries.com I modified one of there kits and its working great

 

Here's one I made for my '36 Ford pickup. 3/8" and looks overkill to me now but it works.

 

Another I made recently but haven't tried yet. Also 3/8"[/URL][/IMG]

 

Hanging pedal setup in 3/8" steel





Hanging pedal setup in my Willys in stainless 3/8"

 

Ok ...from an engineering point , the depth ( dimension perpendicular to the thickness ) of the pedal arm is more important than the thickness. The GM PU pedal ass'y I used is 7/16 thick ,about 1 inch wide at the pedal and about 1-1/4 wide at the pivot. The thinner the material the more the arm will twist under load. 1/4 is too thin.

 

If 1/4" is too thin why do a lot of stock cars have stamped 1/8" pedals ?

 

If they are stamped into a U or C shape they can be more than twice as strong when the additional width is factored in. Any lips or beads stamped in can also increase strength.

Like most things, the total combination of requirements needed dictates the design. In the case of pedal arms; space available, length, possible offset, weight, any manufacturing costs, etc.

It's always nice to be able to fab things spot on the first go. That said I usually grab what "looks like might work" from what's readily at hand and have at it. Then I check carefully as to how it works and then watch how holds up. If I think it needs to look better for appearance alone I'll go back and make a prettier version, possibly adding to, or subtracting from, the original in some way. I wind up with a lot of "wall art" but it works for me.

Ed

 

Precisely my point Ed, design it right and 1/8" is fine

 

Not only thickness, or shape, but material tensile strength too! Some factory arms are pretty high tensile strength to allow them to be thinner. I usually try to find a good factory donor pedal assembly at a wrecking yard, and modify to my car. If it's factory engineered I know it's proven, and saves me some fab time too.