47-55.1 Brake pedal height

[TX3100Guy]

My son and I were sitting in my 1953 Chevy truck today. My son is much taller than I am and he mentioned that he has a hard time getting his longer leg onto the brake pedal without his knee hitting the steering wheel and/or his shins from hitting the under dash. It was then that I also realized that the stock brake pedal is about an inch and a half taller than the clutch pedal.

I have the stock pedal mechanism hooked up to a new under floor - frame mounted master cylinder. In looking at the pedal itself, the top of the brake pedal seems to be welded to the pedal itself (the part the rubber backing is attached to). Under the hood the pedal shaft is flattened on the end with a hole drilled though it for mounting to the mechanism that goes back to the master cylinder.

Does anyone sell a shorter pedal or one with more adjustment? I guess I could also remove the pedal, cut off an inch or two and then grind a flat on both sides for a hole to be drilled for the attaching bolt. But this sounds rather inelegant and a bit of guessing as to how much to cut off. Any thoughts on how to remedy this are welcome.

[mr48chev]

Funny thing is that from the mid 30's until he didn't drive anymore my uncle who was about 6' 4" and drove the 30's, 40's and 50's trucks with his last truck being the 71 GMC that I have now and I never heard him fuss about leg room.

If I were to hack up a pedal so he didn't have to lift his foot so far I woudl get a pedal from someone rather than using the one out of my truck, that way when the idea doesn't work right you can put the original pedal back in and go again. The pedal has that much travel because that mechanically matches the max travel of the piston in the original master cylinder. If the pedal bottoms out before the master cylinder piston stops moving because of the pressure against the fluid you don't have any brakes.

Or you could just tell him to wear his driving shoes when he drives the truck. I've got one car that some of my shoes just flat don't work in because they are are too big and clunky.

[TX3100Guy]

Originally Posted by mr48chev

Funny thing is that from the mid 30's until he didn't drive anymore my uncle who was about 6' 4" and drove the 30's, 40's and 50's trucks with his last truck being the 71 GMC that I have now and I never heard him fuss about leg room.

If I were to hack up a pedal so he didn't have to lift his foot so far I woudl get a pedal from someone rather than using the one out of my truck, that way when the idea doesn't work right you can put the original pedal back in and go again. The pedal has that much travel because that mechanically matches the max travel of the piston in the original master cylinder. If the pedal bottoms out before the master cylinder piston stops moving because of the pressure against the fluid you don't have any brakes.

Or you could just tell him to wear his driving shoes when he drives the truck. I've got one car that some of my shoes just flat don't work in because they are are too big and clunky.

I did find a few brake pedals on eBay. I was thinking the same thing about boogering up my original pedal.

[nvrdone]

many, many years ago I had the same problem. So we took the brake pedal out & cut it to the same length as the clutch pedal. The back of the pad is 7" from the floor and I have no problems with my knee clearance. I'm 6'2" on a good day. I have a dual chamber master cylinder under the floor on an aftermarket mount with 4 wheel drum brakes. system works good.

[TX3100Guy]

Originally Posted by nvrdone

many, many years ago I had the same problem. So we took the brake pedal out & cut it to the same length as the clutch pedal. The back of the pad is 7" from the floor and I have no problems with my knee clearance. I'm 6'2" on a good day. I have a dual chamber master cylinder under the floor on an aftermarket mount with 4 wheel drum brakes. system works good.

I just bought a brake pedal on eBay for $20 after I measured the clutch at 7 inches from the back of the firewall and the brake pedal is 9 inches. When I get the eBay pedal I'll cut the shaft right behind the pedal, cut some off and then weld it back together.

[dsraven]

if changing the length of the pedal, so it is closer to the floor, you MUST ensure that a full PEDAL STROKE cycle will result in a full MASTER CYLINDER stroke. especially if you are running drum drakes anywhere in your system. if this doesn't happen, full stroke of pedal equals full stroke of master cylinder plus some room for component wear, floor coverings under the pedal etc, then your unit is really not safe and legal to drive on the roads with the rest of us. just think about it for a minute, one thing that you must not mess with is the safety items on the vehicle. brakes and steering are a couple of the most important ones in that category.
if the pedal height is too high and you want to lower it then the best way to achieve that is for you to configure the geometry of the linkage to place the pedal at the height you want it and also allow for a full stroke of the master cylinder before the pedal hits the floor.
please seriously think about what you are doing when you modify a safety system that has the potential to cause injury or death to you or someone else if something were to go wrong. yes, it will work great under ideal conditions when everything is adjusted correctly etc, but it isn't usually ideal conditions that cause accidents.

[Wrenchbender Ret]

I have had a lot of these trucks through the years. I have always cut some off the pedal shaft & rewelded to the pedal.
If you need that extra fraction of an inch of travel in the master cyl. you are already in a bunch of doo doo.
It bis safer with the pedal lower as you don't need to get your knee up to your chin to put on the brakes.

George

[TX3100Guy]

Originally Posted by Wrenchbender Ret

I have had a lot of these trucks through the years. I have always cut some off the pedal shaft & rewelded to the pedal.
If you need that extra fraction of an inch of travel in the master cyl. you are already in a bunch of doo doo.
It bis safer with the pedal lower as you don't need to get your knee up to your chin to put on the brakes.

George

Thanks. I’m not anticipating a safety issue once I trim the pedal I bought on eBay. 1) I installed rotors and calipers on all four corners, 2) I also installed an electric hydraulic pump. As a result, I’m certain the truck will stop on a dime before the pedal hits the floor.

[leegreen]

It is worth checking that you get near full stroke of master before anything else stops the pedal. Functional brakes are more important than comfortable brakes!

Since you have a dual master, what is more important than full stroke is enough stroke.

With carpet and everything else installed, brakes fully bled and adjusted, engine off and pressure/vacuum accumulator empty. Have a helper simulate a brake failure by cracking open a rear bleeder, push the pedal, do you get a firm pedal on the front circuit before hitting floor?

repeat the test with a front bleeder

If the pedal goes all the way to the floor with either brake circuit failure you could make your truck safer by fixing it.

With a single pot master you can't do this test and you have no service brakes with any hydraulic failure

[Robert Crandall]

The original poster does not mention how much pedal remains when the brakes are applied. I think that measurement will tell him how much he can give up. My 1950 GMC matches poster TX3100Guy's at 9" at rest. With brakes applied I have only 3" remaining for wear, etc. I am not willing to give any of that up, so I will not consider shortening the pedal. My truck is dual master cylinder with front disc brake conversion.

[mr48chev]

Originally Posted by Robert Crandall

The original poster does not mention how much pedal remains when the brakes are applied. I think that measurement will tell him how much he can give up. My 1950 GMC matches poster TX3100Guy's at 9" at rest. With brakes applied I have only 3" remaining for wear, etc. I am not willing to give any of that up, so I will not consider shortening the pedal. My truck is dual master cylinder with front disc brake conversion.

I have to believe that a lot of people are spoiled by late model cars that have pedals that are only 4 or so inches off the floor and when they get in an old rig it becomes a challenge because they have to lift their foot higher.

In my 77 C 30 or the 77 f250 I am using as a daily driver it is an effort to raise my foot to get on the clutch pedal. You actually have to think about lifting your foot high enough. I think that is what is going on here and would be the same with me if I were to drive my 48 right now, It's a lot different then the BMW or Monte Carlo.

[leegreen]

TX3100guy: "It was then that I also realized that the stock brake pedal is about an inch and a half taller than the clutch pedal."

That does not sound normal to me, neither of the ADs I have had looked like that. Do you still have the rubber bumper that stops the brake pedal on it's return stroke?

[e015475]

My clutch pedal was about 1-2" higher than the brake before I modified it.

I use a Corvette dual master with a booster.

I trimmed both down so I still had full travel on the clutch and brake masters as well as angling the pedal slightly for little bit better ergonomics

6'3" with a stock seat.

[dsraven]

like LG says, check the firewall side of the pedal lever to see if the rubber bumper is still there. I distinctly remember the sound my dads old task force clutch pedal made when the rubber hit the firewall when he was shifting etc.

[leegreen]

Didn't have time to type this before:

before I built my firewall dual pedal set I measured all the cars in my fleet including a bone stock '53 AD that ran when parked. With the seats and tilt columns adjusted to suit me. that included 3 gm trucks, a Camaro and a b5.5 VW

Distance from floor to pedal, pedal travel, distance from pedal to wheel, distance from wheel to edge of seat, distance from pedal and wheel to lumbar of seat. All were very close to each other and a '99 sierra and '53 AD were pretty much identical - so that is the set of measurements I used.

It works OK, clutch could have been a touch lower yet the travel is nearly identical to '99. I think the AD puts you more upright. I'm 5'11" though

And BTW the 2 pedal in that '53 were the same height

[mr48chev]

I know that my pedals don't have the pedal bumpers that Go on the pedal arms before you bolt the shaft from the pedal to them and those would drop the pedal down maybe 1/2-3/4 of an inch. One of those OBTW things that I at least forget every time I put an order together.

[TX3100Guy]

Originally Posted by leegreen

TX3100guy: "It was then that I also realized that the stock brake pedal is about an inch and a half taller than the clutch pedal."

That does not sound normal to me, neither of the ADs I have had looked like that. Do you still have the rubber bumper that stops the brake pedal on it's return stroke?

i do have the rubber bumpers on both the brake and clutch pedals.

[dsraven]

the rubber bumpers also set the brake pedal height so it is the same with each release of the pedal. this allows the master cylinder pushrod to be adjusted correctly so the internals in the master will allow the cylinder to A) release the pressure in the system properly after the brake pedal is released. this is important because otherwise the brakes may drag when the fluid gets hot and expands. B) this allows the piston to retract far enough so the brakes can be "pumped" to make up for fluid loss or out of adjustment drum brakes