CCSBT20

Hey guys first time doing brakes on the '75. When depressing the brake calipers I get just a tiny amount of seepage from the pistons. I was wondering if this was normal? Only replacing brakes due to brake noise pedal is wonderful. Just wondering if its something I should worry about or if its just the style of brake system.

speedreed8

No. probably worn lip seals or bore is pitted if they are oem. Time for rebuild or exchange.

DUB

ANY leak in a hydraulic system is not good.

This is due to when you put new brake pads on and the fluid in the system has been neglected and it black and there is sludge in the bottom of the master cylinder reservoirs....when the pistons of the caliper get pushed back into the bores...either the sleeves/bores have wear in them due to excessive bearing play and/or rotor run-out...or it is the crappy fluid in the bores of the caliper is now not allowing a good clean surface for the seal to seal against when pressure is applied to the system .

This will occur on both design of caliper seals...the original lipped seals or the 'O' ring design.

Also not knowing how you compressed the pistons back into the caliper can cause this ...especially if you were doing this quickly and not allowing the fluid to slowly back flow back into the master cylinder. I always open the bleeder when I am pushing the pistons back in so I am not putting them under unneeded stress.

New brake hoses for the front calipers are MUST!!!

Be careful on where you buy the calipers due to some auto parts stores sell whatever. I have seen it first hand. What may look correct from the outside means nothing when what is most important is what is inside the calipers. I always get my calipers from Lone Start Caliper out of Texas.

DUB

HeadsU.P.

No, not normal and yes you should worry.
Its toast. Take the parts you want off of it and keep it for a core charge. If you want an exact replacement, NAPA about $80. Each corner of the car has a different caliper part number so check your needs.

And ps. Soak the caliper bolts and brakeline fitting with PB Blaster overnite.
Plug the brakeline with something or the rears will drain the master cyl, not good.
Use LocTite Blue on bolts when installing.
Dab some anti-seize on bleeder threads.
And we will see you in a couple days when you start bleeding the system.

san

Rebuild kits for calipers are cheap. Just did front and back on passengers side. No special tools required. The cylinders will pop right out almist by hand.

Tampa Jerry

Before you order a rebuild kit, open up the calipers and see if they have been sleeved in stainless steel. If not, trade them in or have them rebuilt by one of brake vendors. If you trade them in, consider using O-rings instead of lip seals on the pistons and make sure you get back Delco or Moraine calipers back. Lastly a tip. while the calipers are still mounted on the car, break the bolts holding the calipers together. Without an air wrench, it is difficult to loosen the bolts. Good luck. Jerry

71VetteLover

Over time crud builds up in the bore behind the pistons and when they're pushed in the lip seals ride up and over that crud which will cause some leakage And if the pistons are pushed in a little bit cockeyed they'll leak a little bit. So what you're seeing is normal.

san

I would have to agree...mine had no corrosion, just sludge....the lip seals looked fine as well. I would almost guess if you just popped them apart and cleaned them they would stop leaking...but for 20 bucks i figured why not. The guy at the parts store didnt ask me if they were lined or not, i just got the stock parts, lip seal style, everything fit fine and yes mine were lined.

DUB

FOR WHATEVER THIS IS WORTH:

I can say that if a person is installing the lipped seals in their calipers...they just do not 'pop' right in.

There is special tool that compresses the seal while installing it into the bore.

Some people use a feeler gauge, modified tongue depressor or make their own tool that allows them to shoehorn the seal in place correctly.

Personally/professionally 'speaking'.... I do not use 'O' ring style calipers....I prefer the lipped seal design.

DUB

san

Pop right out!!! I dont recall anyone saying pop right in, although the oring style probably would. Putting them in requires a little percision and patients. The easiest way is to buy new calipers, but you get what you pay for. I prefer to rebuild myself, then i know what i got. If pieces cant be rebuilt then its time to replace, i hate any leaks on vehicles. Still have one left on my 78. Power steering control valve, cant seem to go down in fluid, but makes the typical 2 little spots after parking. May try some power steering stop leak...it leaks now anyways, worth a shot!!

DUB

I did not quote you nor was I referencing anything specific that you wrote....I was simply stating what I know to be true for me.

Installing lipped seals in a caliper does take time and some effort and as I wrote... some type of tool to help the lipped seal go into the bore without damaging it.

As for O-ring type seals..I do not mess with them at all.

DUB