Baffling brake problem

[Skip Fix]

Well this was originally my autocross car now switched to a drag car 79 Camaro/500" Pontiac motor.But you guys are good at brakes.

Last outing this spring in the IA/Camaro ran 10.33@ 132.5 butsecond convertor was still to tight only 60 fting 1.54, so ordered one from Lenny at Ultimate. Car has sat since those runs because of COVID and 100 degree weather. Last weekend get in it to move it to the lift to swap convertors and brake pedal has a LOT of travel and is only making 800 psi at the floor front and back. But would hold that pressure not bleed down. Line Lock would hold pressure. Was making 1100 before . 1.03" Mopar MC . Hurst Line lock acting as my T for the front lines. SS flex line to Wilwood Dynalites 4 piston 1.75" on the front. Adjustable prop valve in the rear line. Rear is 79-81 TA brackets and rotors and 2.5""metric" caliper on it. Can't find a leak anywhere.

This weekend it is down to 600 psi at the floor and by hand I could push the pedal 2" before any pressure is made. Took the lines off at the MC and plugged it and pedal barely can move 1/8" like a well bled MC. Still no leaks. RF wheel is pretty tight to turn by hand, a lot more than left. Rear seem to move OK but spinning rear end/trans would make it a little harder.

Any thoughts? Stuck piston in the Wilwood?

[andrewb70]

Possibly an internal leak in the MC.

Andrew

[Skip Fix]

Andrew that is what I was thinking at first until I plugged it and it had no excessive travel and hard pedal. I was about to pull it and swap on a a back up 0.94 " is why I plugged it.

[Skip Fix]

Update-the past two weekends bled the crap out of it since it I unhooked lines at MC. I could pump it up. Right front I could barely spin by hand left intermittently the same. I could pump it now and get 1000psi but then get crappy pedal. Pumped up then using line lok on front it kept a good pedal so seemed like that localized it to front. Plugged lines at the calipers.First one better, second one almost normal. Even releasing pressure did not free up the calipers on the rotor. So they are not releasing. I even had to use a pry bar to slide the right off the rotor and the left was easier but would not pull off easily. Pulling the pads off the outer pistons are 0.080 more out of the caliper on the right than the inner,and 0.060 on the left. Thinking we got some sticking pistons.

[Skip Fix]

Newer update-put two new Wilwood calipers on and have a nice linear pedal again and making 1000 psi . With just one caliper on easy to hit 1200. Rear GMs hit 800.

Old calipers to get sent back to Wilwood for a look at and rebuild for back ups.