[Gator67]

I'm setting up my 70 Formula for manual brakes, and went to switch the clevis pen on the pedal to the upper hole, but ran into a snag. I found that the upper hole is bigger than the lower hole, so the pin is loose. Are the holes on the brake pedal supposed to be the same size, or is there a different clevis pin for the upper hole?

[JUDGE3]

had not heard of that, I converted to manual for mine also and the pedal did not have the second hole. purchased a repop auto trans brake pedal for a 69 firebird, direct bolt in has the 2 holes and the clevis pin was a direct fit.

[455hota]

Here is my spare 70 auto pedal assembly:


And here is my spare 70 manual pedal:



Let me know if you need any difference pics.



Sent from my iPhone using Tapatalk

[JUDGE3]

could you get manual brakes on a 70 and up firebird?

my original pedal (pics) was for auto trans power brakes. the top hole is larger as it bolts on the bracket for the brake lights. the pin below is for the MC/ booster rod.

my repop 69 firebird auto trans manual brake pedal has 2 same size holes.

I used the top hole as required for my manual brake conversion and fabbed my own bracket to use the bottom hole for my brake light switch activation. used a new bolt sized to the hole.


the new pedal is a direct fit putting the foot portion in the same location. only difference is the 69 has the curved frame my original is straight. works great. I suspect the larger upper hole your finding is where your brake switch bracket was. no 2 holes for a manual master cylinder rod.

got my MC and rod kit from master power brakes.

[Gator67]

Not sure if non-power assisted brakes were available in '70. I thought so, but maybe not.

The brake light switch bracket was attached with a bolt in the upper, larger, hole on my pedal. So assuming the upper hole is not intended for a manual brake pushrod, I'm wondering if it's at about the right spot for it? How far up from the bottom hole is yours Judge3? Can always use an aftermarket adjustable MC pushrod but it needs to be at the right spot on the pedal.

[Formulabruce]

I have parted a few 1970's with Manual disc brakes. 90% of the 6 cylinder cars had them, and many base model cars. I have a 72 out back, auto with manual brakes. Pedal is in it.

[JUDGE3]

so you could get manual brakes. wasn't sure about that.

can't provide a measurement from bottom to top hole as mine is installed, I do have a nice straight level from rod into mc however.


contemplated welding in the bracket hole and re-drilling for the clevis pin but deemed it to much trouble with the repop being 35 bucks.


would like to see pictures of the original manual brake pedal installed. would show how the switch as well as the rod looks. see how close I am to stock.

[Gator67]

After doing some geometry, it looks like the upper hole is in about the right spot for manual brakes (about 6 to 1).

Then I spent some time with the assembly manual and discovered that there are different clevis pins for manual and power brakes. The pin for power brakes, which goes in the lower hole, is # 3975544. The pin for manual brakes, which goes in the upper hole, is # 3965696. Interestingly, the retainer clip is the same for both pins.

Anyone have a clevis pin the the manual brakes available? It should be just under .50" diameter (whereas the power brake pin is around .43")

[JUDGE3]

I did not find a reproduction manual pin/rod. must be a different brake switch bracket as well. with the clevis pin being a different size, would need stock parts as my mp brakes pin/rod was a direct fit for the 69 pedal. 69 pedal has same size holes as did my 69 Gto.