CamaroUK

Hi!

My brother is having a problem with his 94 LT1 Auto Corvette. It failed the annual inspection as the rear wheels have no braking.

So far he has:
Stripped the master cylinder and checked the seals and the proportioning valve.
Checked the brake lines.
Replaced the brake fluid and bled all four corners (a few times)
Checked brake pedal travel.
Checked and resurfaced the brake pads with emery paper.

With the rear of the car on jackstands and the wheels off and the discs spinning at idle speed the brakes can only just about stop the discs after doing this for a couple of minutes the discs were barely warm.

I assume the Corvette has the same brake setup as the F-bodies so I thought I'd ask you guys for any suggestions.

Thanks in advance!
Scott

mr_camaro96z28

I'm willing to bet that the reason it's not stopping quickly is because the abs is freaking out that the front wheels aren't moving and you're trying to stop the rear and it is trying to stop suddenly instead of gradually. It's not allowing much brake pressure to the rear so it's not loking up the brakes. If there's fluid at the rear calipers and you can bleed them the brakes should be working. Try by taking off the caliper and pushing the pistons into the calipr with a clamp loosen the bleeder to allow the fluid to get out while you push in the piston(s). Do this on both sides. Then assemble the brakes and one of you get in the car and pump the pedal while the other watches the calipers to make sure the pistons are moving toward the rotor and of they are you should have brakes if not you'll need a new caliper because the piston is seized in the bore is my assumption.

CamaroUK

I think he tested to see if the caliper pistons were seized and they appeared ok, the calipers and brake lines tense up when the brake is applied but they just have no braking force, both discs on the rear are exactly the same.

I think your point about the abs being confused as the front wheels are stationary is valid, but even on the vehicle testers rolling road they showed inadequate braking force anyway.

Are there any other things to check or try?

mr_camaro96z28

I see he resurfaced the pads but do they have enough matrial still left on them you want the material as thick as the metal. He might try having the rotors turned chances are they might be glazed over and that would cause inadequate braking. I'll ask my boss and see if he has any other ideas.

mr_camaro96z28

The only new news I have is check all the flexibe lines and make sure they're not pinched or in a bind. If none of this is the problem there might be a restriction in the line.