cl3884

This might be a double post as I just made one that disappeared in cyper...
I bought a 1978 Corvette a year ago and I have never had any issues with the brakes until now. I was chasing a clicking sound from the rear end and took the calipers off for inspection of the hand brake assembly.
There was nothing there so I mounted the caliper again and now one piston in the rear left caliper has started leaking. After taking off the caliper I removed the boot and piston in question.
The caliper looks newly rebuilt and the bore is sleeved. The lip seal and the boot looks in very good shape but the pistons are very loose in the bore and easy to wiggle. So I measured the bor and piston as follows: The bore measure 1.378” or 35mm but the piston measure 1.319” or 33.5mm so the clearance is 0.059” or 1.5mm.
My question is whether I have got the right pistons for the caliper?
They look like the standard pistons but I feel there is something wrong.

Regards

Chris

The Punisher

were the springs still in there behind the pistons?

cl3884

Yes - the springs are there.

cl3884

I have attached photoes of caliper bore and piston. Maybe the gab is not so clear.....

The Punisher

you can try new lip seals. The pistons don't fit in the sleeve very tight

DUB

I will measure some pistons I have and get back with you tomorrow.

I can say that that is a piston for the rear caliper.

I do know that the piston can actually move side to side and seem to get locked into position....so...the pistons are not really that tight to the bore.

DUB

cl3884

I found this service bulletin saying that the tolerance should be 0.0039 to 0.009 which means my pistons are too small or the bore too large.
http://www.corvetteactioncenter.com/...pers-1147.html

cl3884

I got new lip seals about two weeks ago and fitted the piston with the new seal and boot. So far it holds tight.

Regards

Chris

DUB

Thanks for the update and I hope it all stays as planned.

DUB