J and H

I changed the automatic brake pedal to a stick brake pedal with clutch pedal. I had to disconnect the master cylinder during the change.

Everything is back together now but after bleeding the brakes three times I am still not getting the right pedal pressure. Any thoughts?

Durango_Boy

There are different holes used on the pedal for the rod that comes out of the master.

You may have that pedal rod pinned to the wrong hole, and your new pedal may not even have the correct hole.

This will change the way it feels. I'm assuming it feels soft to you?

J and H

The pedal did not have a hole to line up for the power booster rod so I drilled one in line with the push rod.
UPDATE.....
I removed the master cylinder and bench bled it, then put it back on the car and bled the brakes.........same result.
Now with the engine off there is pedal pressure, but with the car on I can put the pedal to the floor. This is extremly frustrating.

Durango_Boy

What year is the vacuum booster from, stock I'm guessing, and what year is the master? Same?

Also, the clevis should be adjustable. Is it adjusted all the way out?

J and H

Clevis seems non-adjustable. I can screw it out maybe 1/8 to 1/4"-thats it. If I have not updated yet, I just replaced the M/C-same pedal. Any ideas?

pbcanney

what year is the car?

I just went through this on my 81 (installing a pedal set from a 79)

The clevis is not adjustable on mine (power brakes)

J and H

The vette is a 73. The pedal assembly was supposed to fit-I had to alter two mounting holes on the bracket.
Update-I "extended" the pushrod for the clevis. It added enough length to take out all slack in the brake pedal. I will bleed the brakes tomorrow and see if I can get the pedal feel back. If this did'nt work I will have to take the car to the shop.

Durango_Boy

What I'm thinking is you may have a short snout master in a booster with a short booster pin. That's why I need details about what year booster and what year master you have installed.

pbcanney

but I do find it odd you had to modify the mounting holes. Pedal clusters should interchange through all c3's (or so I've been told)

side by side, the manual and automatic clusters should have looked like twin brother/sister. Unless it's an after market or from something else.

J and H

The power booster slides into 4 holes on the pedal bracket. The top two holes did not line up. The other holes on the mount lined up.
I thought pedal mounts 68 through 82 on C3's should all be the same-same basic car. This pedal assembly was supposed to be for 73 to 76. As far as the year of booster, it appears to be an original 73. The M/C is a rebuilt-unkown year.

pbcanney

Under the hood, in the windsheild wiper 'well', are 4 bolts to hold the cluster up against the upper firewall. Did those line up?

The pedals should sit snuggly like this:


It sounds to me like your pedal cluster (cage/hanger unit/etc) isn't up as high as it should be

J and H

Yep, those bolts in the wiper well lined up.

Anyway, I bled the brakes this morning and did not notice any change. I decided to take the car for a slow run just to see. The brakes worked alright at the start, then progressively got better and better.....then they got too good-started slowing me down without any brake application. long story short the front brakes locked up on me and I was stuck until they coolled off. I backed the clevis off 1/4" and I am now able to stop with just the pressure of my big toe.

Now the calipers, pads and rotors had less than 5 miles on them. I think the pads broke in on the rotors or vise versa. I dont know whats up with the pedal pressure going up as I drove it. I can say I am thankfull for everyones time here.

any4xx

I'm new to this conversation so forgive me if this has been covered elsewhere. It sounds like your M/C piston is remaining partially depressed, thus not allowing adequate return. As your front brakes warm. the fluid expands and instead of flowing back into the M/C, it's applying the brakes.