sticking front brakes

fishman · Post by **fishman** » Thu Apr 19, 2007 12:13 am

I took off the front brakes of my disc brake race car....i sanded down the rotors and the pads as they have glazed from racing...i installed them back on the car and then pumped the brakes up to set the wheel bearings and i couldn't turn the wheel as it was to tight like the piston is not returning.....so i went and bought a new set of calipers and the same thing is happening...i haven't bleed them yet.....have you see this problem before i think the rotor isn't warped as it is tight evey spot not just one spot.....should i try to drive the car to see if it will free up or do u guys have something else i can look at ........thanks

mcbrake · Post by **mcbrake** » Thu Apr 19, 2007 9:54 am

First you need to identify the source. Install all parts and make sure system is bled properly. Then apply the brakes a few times and make sure the fronts are locked. Take a bleeder wrench and open bleeder.
If squirt of fluid and frees up, see if both sides freed up, if the did your problem is hydralic lock up- probable master cylinder. If no fluid and still locked you have a mechanical problem- spacing of caliper, pads, rotor.
Jake

kjkens · Post by **kjkens** » Thu Apr 19, 2007 11:46 am

No you should not try to drive the car. First find out what is wrong. You say you have not bleed the brakes yet but I am assuming that you have pumped the pedal with the new calipers on. When you installed the new calipers did the rotor turn before you hit the pedal? If not you have a mechanical bind you need to address. If the rotor locked up only after you stepped on the brake then you probably have a fluid pressure problem. Without the pedal applied, try to turn the rotor, if it will not turn then break the bleeder screw loose. If the rotor now will turn you have pressure in the line keeping the brakes applied. Try breaking the line loose at the master cylinder and if the rotor turns next try it by loosening the bolts a few rounds that hold the master cylinder to the firewall or booster. I have seen several that the master cylinder is the wrong application for the car, pedal pushrod not adjusted properly or contaminates in the fluid that swells up the rubbers in the master cylinder preventing the fluid from returning to the reservoir. If you need additional help email me your phone # and I will call you with the diagnosis procedures

fishman · Post by **fishman** » Thu Apr 19, 2007 6:13 pm

Hi guys

Reading my post i missed out some info....only the passenger side caliper was sticking and after repalcing with new calipers only the passenger side is still sticking......anyways i took off the brake hose completely to see if the piston would return it wouldn't.....so i took the caliper right off and the piston would not move with both the brake hose hole open and the bleed screw out....i tried to push it back in and it would not move.....so i took it back to the place i bought it and he used a clamp on it and said all was wrong was it was hanging up on the rubber............so i took it home and tried it again and same thing..........has to be the caliper what do u guys think........thanks

PackardV8 · Post by **PackardV8** » Fri Apr 20, 2007 12:56 am

Hi, fishman,

What hose are you using? If it is rubber, it could have deteriorated inside and blocking the fluid from releasing back. Seen it happen.

thnx, jv.

fishman · Post by **fishman** » Fri Apr 20, 2007 1:08 am

It is rubber the hose and i thought maybe the hose was plugging it off to but with the brake hose off and the bleeder screw out the caliber piston still wouldn't retract....that is why i am thinking there is something wrong with the caliber....it is wierd because that is the side that stuck in the first place....but with the old caliber there was junk inside the piston and grooves holding the piston from returning....

Cammer · Post by **Cammer** » Fri Apr 20, 2007 3:44 pm

Just a little brake hose info:

Rubber hose metal parts frequently corrode/rust and slow or stop fluid flow.

Newer hoses have teflon liners so be careful when clamping or you can crush liner.
________________

trikesrule · Post by **trikesrule** » Thu May 03, 2007 3:54 am

Ran across this problem before. The rotor was under size and the piston was coming out too far and getting jammed up on the edge of the caliper and could not return. Rip the caliper and rotor off and get your brake guy to measure the rotor and make sure it's not under thickness..........trikes

fishman · Post by **fishman** » Wed Jun 20, 2007 11:42 pm

well i finally resolved my sticky front brake issue....the caliper was hittong on the bracket that holds the caliper...so i marked it with a paint stick and took it off and ground down the part that was hitting...put it back on thinking oh great no more problem now......well it was still sticking...so i took the caliper off again and miced the top of the bracket and the bottom well the top was closer by 16 thou and rubbing on the top of the brake show....so i bent the bracket to the same clearance as the bottom and now it works finally .......one more thing off my list that has been a pain in the ass......thanks

trikesrule · Post by **trikesrule** » Thu Jun 21, 2007 5:04 am

Well done Fishman. Whats next?.........trikes