I posted this on the pre-92 link but thought I'd try it here too for as many opinions as I can get before I spend bucks unnecessarily. I got a good one for you guys! I recently changed the front rotors and pads on my 90 Civic LX sedan. I drove it and the pedal kept going almost to the floor so I bled it thinking maybe that was it even though I never cracked the line open. That didn't help. No evidence of a leaking master cylinder either. Put it back on jack stands and took the wheels off and then started it and put it in gear and let it go. The passenger side spins but not the driver's side. I pushed the piston back in on the driver's side and tried it again and it would spin. As soon as I applied the brakes, it stuck again and wouldn't spin. Any ideas on what would cause that? Maybe a bad caliper all of a sudden? Thanks guys for your ideas and suggestions.

 

You didn't mention how you pushed the pistons in. If you just used a C-clamp or whatever tool without opening the bleeder screw, you're forcing yucky blackened brake fluid back up into the master cylinder. If there's chunkageness in the fluid, it could have kept one of the check valves in the master cylinder, proportioning valve, etc. in the open position. Bleeding probably won't be enough to clean the crud out - the damage is already done. The correct way is to first crack open the caliper bleeder screw and capture the fluid as you push the piston in.

If the fluid level was really low, you may have ingested air in it which, of course, requires bleeding.

If the piston doesn't retract on it's own, the only way to fix it is to either replace the caliper or rebuild it. If the caliper is equipped with sliding pins, they must be clean (and lubricated if recommended) so they don't hang up either. The O-ring on the piston has a squaureish cross section. It's designed to be "grabby" to the caliper bore up to a limit at which point it will eventually slide. In operation, the piston only travels a few thousandths of an inch, so the O-ring is supposed to provide the "spring back" return force so it actually lkifts the piston a tiny amount away from the rotor. In other words, the O-ring acts as the piston return "spring". It should only slide on occasion to take up pad wear. With enough heat cycles and high temperature, the O-ring eventually loses it's elasticity. It may still seal, but can no longer prevent the piston pad from dragging.

 

Hmmm. Good info! I did just use a c clamp but didn't open the bleeder. I think I'm going to replace the calipers and see if taht fixes it. If not, maybe a power flush of the system. Thanks.

 

OK, I replaced the calipers and bled the system. STILL STICKING in driver's side. Could it have something to do with the CV axle? I changed the engine and maybe when I pulled it out or put it back in I screwed something up? I know it'll drive because I test drove it after I changed the engine. I can push the piston back in and it will spin (not as freely as the passenger side but will spin) but when I step on the brake it sticks again. Any ideas???? Thanks and Happy Thanksgiving to all!

 

^ ^ ^ ^

 

sounds like a bad master cylinder........

 

Would that cause it to stick on only one side?

 

Can anybody think of anything else that would cause the caliper to stick or whatever it is?

 

Anybody????

 

Gotta be a master mechanic here that knows their stuff in the area I'm having the problem. I don't want to keep throwing money at it until I luck up and stumble on the fix. Thanks guys!

 

Short of incorrect assembly or any other surprises not previously divulged, that's pretty much it. Anything could have happened, but it's difficult to be able to identify any of a plethora of far reaching possibilities. We are rather limited by not actually being there in person. Everything's already been covered.

 

Do you have a dual master cylinder that operates left front and right rear and vice versa? If so, that would explain only one front wheel sticking. It could be the brake line itself with a blockage that can be overcome by the pressure of applying the brakes but does not release the pressure when you come off the brake. Remember the lines are steel, may have the original fluid which is hygroscopic. It absorbs moisture and can cause problems in the lines. I would try bleeding out the complete system to get all the crap out.

 

One more thing. Because you have replaced the front calipers they may have now been contaminated with crap from the old fluid. I would disconnect the offending brake line and bleed it out first, then connect it to the caliper. and bleed again.

 

Which reminds me: You weren't foolsih enough to put DOT 5 racing brake fluid in your car, right?

 

No I used DOT 4. I didn't take the lower pin out of the rebuilt caliper and lube it. It had some silicone grease on the rubber boot so I assumed the pin was lubed. I plan to take the caliper back off and take that pin out and lube it up real good and see what that does. I'll also hit that upper pin again real good. It spins fine when I push the piston back in but when I hit the brakes and release it sticks. Hope it's just that lower pin needing to be lubed up. Thanks for all your ideas/recommendations guys. This site is so awesome!!!!