Brake caliper leaking?
Thread Starter
Pro
Joined: Jun 2000
Posts: 732
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From: Goshen NY
Brake caliper leaking?
I have installed new brake calipers and MC on my 1980 vette. I bleed the rear brakes – no problem. My daughter got her first lesson in auto mechanics by being the brake pedal pusher. I tried to bleed the front brakes but was unable to get brake fluid to come out the bleeder valves. So I checked to make sure the MC was spitting out brake juice – no problem there. I check to make sure brake juice was getting to the fitting on the caliper – no problem there. So why was brake fluid not going into the caliper. My next experiment was to connect a clear hose to the bleeder valve and attempt to siphon brake fluid by mouth (it was late at night and I do not have one of those vacuum things…call me crazy). No success? For some reason any air I sucked out of the caliper was being replaced by more air and not brake fluid. Next experiment…I took some soapy water and applied air pressure – by mouth – and check for air escaping from fitting etc. Fitting were okay but I did notice that around the seals of the caliper piston some air leaking. Is this supposed to be like that? Is this a good test for leaking calipers?
Cruising
Joined: Jul 2007
Posts: 14
Likes: 0
From: South Jersey
I'm by no means an expert....but I've had more than my share of trouble with the brakes on my 70. The rears are nice with bleeders on both sides of the caliper and have never given me issue ,but the fronts only have the bleeder on one side and seem to be VERY prone to trapping air. Recently I bought new front calipers and seemingly got a bad one out of the box as it would not bleed properly no matter what I tried. I eventually returned it last week and the new one has performed good so far. So buying new/rebuilt doesn't always seem to be a perfect science. I'd recommend returning the problematic caliper first, and then if you still have the issue look at the master cylinder and brake line.
Good luck.
Good luck.
Thread Starter
Pro
Joined: Jun 2000
Posts: 732
Likes: 0
From: Goshen NY
Yes, I tried the soapy water on the hoses etc. My thinking is that any air I suck out of the caliper is being replaced by air leaking past the piston seals. The small spring force inside the calipers piston is enough to draw air in but not brake fluid.
Premium Supporting Vendor
Joined: May 2000
Posts: 4,312
Likes: 70
From: Clearwater FL
You should always replace the flex lines when you do a caliper job. Putting soapy water on the lines is not going to determine your problem if it's a hose as they colapse on the inside, not leak through a hole on the outside.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
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From: New Hill NC
Yea, I didnt mean check the hose for leaks, I meant check it for blockage.
Premium Supporting Vendor
Joined: May 2000
Posts: 4,312
Likes: 70
From: Clearwater FL
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