passenger brake caliper locking up

[zrk666]

i have a major problem with the passenger side brake caliper that is locking up. i have replaced pads on it many times and the rotor looks to be fine but yes it could be warped. i have rebuilt the caliper and about a month after that it started grabbing again. there is no fluid leaking, and the hard lines are not pinched.

so here is my question.

i want to know if it could be the caliper locking up, rubber line has colapsed inside of itself, or the brake booster, master clynder is not pushing the amount of fluid that is needed?

 

[lasertim]

When you bleed it does the fluid flow like normal and the bubbles disapear?

Also, when installing new pads do you lube the slides and apply antiseize to all metal to metal contacts?

 

[wret]

When you rebuilt the caliper, did you hone the cylinder? If not and there was corrosion present, you may have only freed it temporarily until the rust got a grip again.

 

[zrk666]

When you bleed it does the fluid flow like normal and the bubbles disapear?

Also, when installing new pads do you lube the slides and apply antiseize to all metal to metal contacts?

yes the fluid flows normal, yes i lube the slides and put antiseize to the contacts.

 

[zrk666]

When you rebuilt the caliper, did you hone the cylinder? If not and there was corrosion present, you may have only freed it temporarily until the rust got a grip again.

we honed the cylinder but you might be right on that one because it might of freed it somehwat but came back. it has been so long that it is kinda hazy in my mind on exatly what went down. all i really know that it is giving me a real hard time to go. i might just end up putting a new caliper oem replacement on there.

thanks for the advice/help.

 

[toybreaker]

Sticking/siezerfied brakes on one corner can be really unsafe in a panic stop, so I'd get on that ASAP. It sounds like this is an ongoing problem.

You should be able to tell what's going on with a little bit of investigation.

Is one pad worn/smoked more on that caliper than the other? Is the other front pad set worn ~ the same?

If the outer pad is smoked, or has a lot of taper wear, I would suspect the caliper slider pins are hanging up in the caliper carrier bracket. Remove the pins and rubber bushings from the carrier, and wipe them clean. Use brake clean and a bottle brush to thoroughly remove all the old grease/rust etc. from the carrier bores, and blow them out with compressed air.

Sta`lube makes an awseome synthetic moly brake grease for sliders. It's available in tube, and tub with a brush form. Put a little grease on the tip of a screwdriver and wipe it inside the carrier bore. Insert the slider pins fully, and remove them a couple times. Wipe off the excess, especially the groove where the bushing goes. Lubricate and reinstall the rubber bushings,and you're good to go.

Note, the upper and lower pins are different. there's a letter on the pin's bolt end, and a corresponding letter on the caliper or carrier. It matters where they go, as one pin has a rubber insert to help keep the caliper aligned.

If the piston hangs up/sticks, it can smoke the inner, or even both pads, because it doesn't release the force of the pads against the rotor...it just kind of drags them along.

You can begin the process by seeing if the wheel rotates freely when the car is on stands.

You can then have your g/f stand on the brakes, lightly. Can you rotate the wheel, or it's mate on the other side? Have her release the brakes and check all wheels for a clean release. This will begin the process of narrowing it down. If the amount of drag doesn't change on/off the pedal, (lightly) the piston on that side is pretty siezed. If it feels like the caliper is applying and just not releasing, further investigation will be required. Verify the other side applies/releases correctly.

Give your brake hoses a thorough visual examination. Check the ends of the short hose from the strut to the caliper carefully. Also check the hose where it goes onto the hardline on the inner fender. When a lot of people do pad slaps, the caliper is just left to dangle on the hose. This is very bad because it concentrates all the stress on the hose ends, potentially causing internal damage. Please support your caliper with a coathanger thru the slider pin boss, and wrap the other end around the coil spring of the suspension strut, when performing brake maintainance. Sooner or later, if you just leave it to dangle, or stuff it up out of the way, you'll knock the caliper down, and the brake hoses don't make a very good caliper bungy cord.

In fact, I have seen a couple of stainless lines become restricted and/or leak at the fenderwell and caliper fittings due to poor maintainance practices. Stainless lines are absolutely unforgiving to a caliper drop test. The ss lines don't have ANY elasticity, and the stress concentrates right at the fitting, causing damage to the hose inner liner at the end/fitting connection. This damage is not always visually apparent. A good drop will also begin to pull the hose out of the fitting, weakening it's retention. This will happen most often at the fenderwell and strut hardlines, as well as the caliper fitting. This could potentially show up as a catastrophic failure, at the worst possible time. I.e. when you really stand on the brakes, and need them the most. I don't know about you, but I can really nail the brakes hard when some maroon pulls out in front of me.

It would really suck to have the pedal hit the floor right about then...

If there's ANY doubt about a hose, just replace it

You can check your hoses for restriction by bleeding the brakes a couple times at each wheel. Just put a piece of clear plastic tubing on the bleeder screw, open the bleeder ~ 1 turn, and watch the flow. Gravity will allow fluid to come out, albiet really slowly..If you get a little spurt, without any brake pedal application, you should check the master cylinder push rod for misadjustment. If it's misadjusted, it could cause the master cylinder piston to block the thermal expansion port in the m/c., leading to a build up of pressure in the system as the fluid gets warm, and expands. Checking your wheels after a drive will also tell the tale. It takes awhile to heat up a wheel, if they're all warm, and you haven't been using the brakes much, please throw it back upon stands and recheck for excessive drag when the system is warm. You may have a master cylinder adjustment issue that only shows up hot. If just one gets warm, it's probably a single wheel issue

Now bleed the brakes a couple of times at each corner, opening the bleeder the same amount each time. It should be about the same resistance at the pedal and flow at the calipers on each side. Note the rear fluid has further to go, and is also somewhat restricted at the proportioning valve, so it may not move as freely as the fronts, but should be the same side to side.

When you pull the suspect caliper off the carrier, try and push the piston back into the bore with your thumbs. If it doesn't move, crack the bleeder ~ 3/4 turn and try again. If it moves now, you've got a restricted hose/hardline/incorrectly adjusted m/c. In very rare cases you can develop a "flapper". That's when the hose tears at a fitting, and a piece of it hangs down, inside the hose. It can let fluid flow easily one way, and restrict it the other way. This can cause a problem like yours as well, it's happened to me. ...

Note; this will cause a very slight momentary pull when you get on or off the brakes...this took awhile to find on my 90 gsx...

If it doesn't move with (hard) hand pressure, get a c-clamp, and try again. It really shouldn't take more than hard thumb pressure on the fronts. Make sure you're pushing the piston squarely back into the bore. If it's crooked, it'll be really hard to move.

Note; the rears require turning the caliper piston as the piston is retracted into the bore. They have the parking brake mechanism, which works on the piston internally. Forcing the piston back without turning the piston will damage the mechanism.

If you do decide to rebuild these calipers again, I would closely examine the bores for pitting/corrosion, and the pistons for scratches, and dings. Anything that would hang the piston up. I usually polish the piston with 1000/1500 grit sandpaper, and then THOROUGHLY clean it with brake clean, and give it a wipe with a lint free cloth. There's a couple of ways to prep the caliper bore, from a brake hone to scotch brite...just be absolutely sure you've got ALL of the abrasive out of the casting, and blow it out thoroughly with clean/dry compressed air. Make certain that the o-ring groove is spotless, use scotchbrite or whatever, and a q-tip to remove the residue. Don't use anything but brake clean to clean the calipers. No solvents, or etc...there's just no way to get ALL the residue out of all the passages. Any residue with petroleum in it will swell the seals down the road...weeks or even months later, it'll start to hang up. I usually give mine a final rinse with flaming hot water. Just be sure to dry them thoroughly, and quickly, as they will flash rust quickly.

I always use a rubber grease made specifically for brake hydraulic system rubber parts during reassembly. Castrol/girling, lockheed and others make it, and cool guy parts stores will have it. DO NOT use anything except a product specifically meant to lubricate the INTERNAL parts of a brake caliper. ( the grease for the sliders will NOT work for this) Install your new o-ring, wipe some grease on the bore and piston, and assemble. Applying a good film in the bore will prevent rust, especially on the dust boot side of the o-ring, as this area operates without brake fluid, and is subject to water/contamination from a leaky dust boot down the road. The first time you bleed the brakes, the fluid may come out tinted with red grease residue. Don't worry about it, it's just the extra grease leaving the system. Down in the caliper, plenty remains to give you good lubricity. I find calipers assembled with lube instead of just brake fluid will give much better service, for a longer time, with fewer issues.

Some brake fluid will always wick up the bleeder screw and run all over everything if you open the bleeder too far during the bleeding process. Putting a schosche of rubber grease on the bleeder screw threads will minimize this, as well as help prevent drawing air down the threads on the pedal back stroke during the bleeding process.

Now's a good time to paint them up, and make it all pretty. Engine paint works, but brake fluid will dull/strip it right off. There's some pretty cool brake caliper specific paints available at walmart/autozone etc, now, and I've been using them with excellent results.

I looked at your vehicle profile. Now may be an excellent time to do the 2 piston caliper upgrade, if you haven't already done so. Looks like you're building a fast car, and it will need some kick ass, dependable stopping power. The 2 piston calipers can be had for a song at the boneyards, and if you rebuild them yourself, you can do the upgrade dirt cheap. New rotors and some upgraded pads and you're good to go, AND stop. Best speed mod for the money, brakes wise, imho.

Good luck, and I hope it turns out well this time.

 

[zrk666]

Sticking/siezerfied brakes on one corner can be really unsafe in a panic stop, so I'd get on that ASAP. It sounds like this is an ongoing problem.

You should be able to tell what's going on with a little bit of investigation.

Is one pad worn/smoked more on that caliper than the other? Is the other front pad set worn ~ the same?

If the outer pad is smoked, or has a lot of taper wear, I would suspect the caliper slider pins are hanging up in the caliper carrier bracket. Remove the pins and rubber bushings from the carrier, and wipe them clean. Use brake clean and a bottle brush to thoroughly remove all the old grease/rust etc. from the carrier bores, and blow them out with compressed air.

Sta`lube makes an awseome synthetic moly brake grease for sliders. It's available in tube, and tub with a brush form. Put a little grease on the tip of a screwdriver and wipe it inside the carrier bore. Insert the slider pins fully, and remove them a couple times. Wipe off the excess, especially the groove where the bushing goes. Lubricate and reinstall the rubber bushings,and you're good to go.

Note, the upper and lower pins are different. there's a letter on the pin's bolt end, and a corresponding letter on the caliper or carrier. It matters where they go, as one pin has a rubber insert to help keep the caliper aligned.

If the piston hangs up/sticks, it can smoke the inner, or even both pads, because it doesn't release the force of the pads against the rotor...it just kind of drags them along.

You can begin the process by seeing if the wheel rotates freely when the car is on stands.

You can then have your g/f stand on the brakes, lightly. Can you rotate the wheel, or it's mate on the other side? Have her release the brakes and check all wheels for a clean release. This will begin the process of narrowing it down. If the amount of drag doesn't change on/off the pedal, (lightly) the piston on that side is pretty siezed. If it feels like the caliper is applying and just not releasing, further investigation will be required. Verify the other side applies/releases correctly.

Give your brake hoses a thorough visual examination. Check the ends of the short hose from the strut to the caliper carefully. Also check the hose where it goes onto the hardline on the inner fender. When a lot of people do pad slaps, the caliper is just left to dangle on the hose. This is very bad because it concentrates all the stress on the hose ends, potentially causing internal damage. Please support your caliper with a coathanger thru the slider pin boss, and wrap the other end around the coil spring of the suspension strut, when performing brake maintainance. Sooner or later, if you just leave it to dangle, or stuff it up out of the way, you'll knock the caliper down, and the brake hoses don't make a very good caliper bungy cord.

In fact, I have seen a couple of stainless lines become restricted and/or leak at the fenderwell and caliper fittings due to poor maintainance practices. Stainless lines are absolutely unforgiving to a caliper drop test. The ss lines don't have ANY elasticity, and the stress concentrates right at the fitting, causing damage to the hose inner liner at the end/fitting connection. This damage is not always visually apparent. A good drop will also begin to pull the hose out of the fitting, weakening it's retention. This will happen most often at the fenderwell and strut hardlines, as well as the caliper fitting. This could potentially show up as a catastrophic failure, at the worst possible time. I.e. when you really stand on the brakes, and need them the most. I don't know about you, but I can really nail the brakes hard when some maroon pulls out in front of me.

It would really suck to have the pedal hit the floor right about then...

If there's ANY doubt about a hose, just replace it

You can check your hoses for restriction by bleeding the brakes a couple times at each wheel. Just put a piece of clear plastic tubing on the bleeder screw, open the bleeder ~ 1 turn, and watch the flow. Gravity will allow fluid to come out, albiet really slowly..If you get a little spurt, without any brake pedal application, you should check the master cylinder push rod for misadjustment. If it's misadjusted, it could cause the master cylinder piston to block the thermal expansion port in the m/c., leading to a build up of pressure in the system as the fluid gets warm, and expands. Checking your wheels after a drive will also tell the tale. It takes awhile to heat up a wheel, if they're all warm, and you haven't been using the brakes much, please throw it back upon stands and recheck for excessive drag when the system is warm. You may have a master cylinder adjustment issue that only shows up hot. If just one gets warm, it's probably a single wheel issue

Now bleed the brakes a couple of times at each corner, opening the bleeder the same amount each time. It should be about the same resistance at the pedal and flow at the calipers on each side. Note the rear fluid has further to go, and is also somewhat restricted at the proportioning valve, so it may not move as freely as the fronts, but should be the same side to side.

When you pull the suspect caliper off the carrier, try and push the piston back into the bore with your thumbs. If it doesn't move, crack the bleeder ~ 3/4 turn and try again. If it moves now, you've got a restricted hose/hardline/incorrectly adjusted m/c. In very rare cases you can develop a "flapper". That's when the hose tears at a fitting, and a piece of it hangs down, inside the hose. It can let fluid flow easily one way, and restrict it the other way. This can cause a problem like yours as well, it's happened to me. ...

Note; this will cause a very slight momentary pull when you get on or off the brakes...this took awhile to find on my 90 gsx...

If it doesn't move with (hard) hand pressure, get a c-clamp, and try again. It really shouldn't take more than hard thumb pressure on the fronts. Make sure you're pushing the piston squarely back into the bore. If it's crooked, it'll be really hard to move.

Note; the rears require turning the caliper piston as the piston is retracted into the bore. They have the parking brake mechanism, which works on the piston internally. Forcing the piston back without turning the piston will damage the mechanism.

If you do decide to rebuild these calipers again, I would closely examine the bores for pitting/corrosion, and the pistons for scratches, and dings. Anything that would hang the piston up. I usually polish the piston with 1000/1500 grit sandpaper, and then THOROUGHLY clean it with brake clean, and give it a wipe with a lint free cloth. There's a couple of ways to prep the caliper bore, from a brake hone to scotch brite...just be absolutely sure you've got ALL of the abrasive out of the casting, and blow it out thoroughly with clean/dry compressed air. Make certain that the o-ring groove is spotless, use scotchbrite or whatever, and a q-tip to remove the residue. Don't use anything but brake clean to clean the calipers. No solvents, or etc...there's just no way to get ALL the residue out of all the passages. Any residue with petroleum in it will swell the seals down the road...weeks or even months later, it'll start to hang up. I usually give mine a final rinse with flaming hot water. Just be sure to dry them thoroughly, and quickly, as they will flash rust quickly.

I always use a rubber grease made specifically for brake hydraulic system rubber parts during reassembly. Castrol/girling, lockheed and others make it, and cool guy parts stores will have it. DO NOT use anything except a product specifically meant to lubricate the INTERNAL parts of a brake caliper. ( the grease for the sliders will NOT work for this) Install your new o-ring, wipe some grease on the bore and piston, and assemble. Applying a good film in the bore will prevent rust, especially on the dust boot side of the o-ring, as this area operates without brake fluid, and is subject to water/contamination from a leaky dust boot down the road. The first time you bleed the brakes, the fluid may come out tinted with red grease residue. Don't worry about it, it's just the extra grease leaving the system. Down in the caliper, plenty remains to give you good lubricity. I find calipers assembled with lube instead of just brake fluid will give much better service, for a longer time, with fewer issues.

Some brake fluid will always wick up the bleeder screw and run all over everything if you open the bleeder too far during the bleeding process. Putting a schosche of rubber grease on the bleeder screw threads will minimize this, as well as help prevent drawing air down the threads on the pedal back stroke during the bleeding process.

Now's a good time to paint them up, and make it all pretty. Engine paint works, but brake fluid will dull/strip it right off. There's some pretty cool brake caliper specific paints available at walmart/autozone etc, now, and I've been using them with excellent results.

I looked at your vehicle profile. Now may be an excellent time to do the 2 piston caliper upgrade, if you haven't already done so. Looks like you're building a fast car, and it will need some kick ass, dependable stopping power. The 2 piston calipers can be had for a song at the boneyards, and if you rebuild them yourself, you can do the upgrade dirt cheap. New rotors and some upgraded pads and you're good to go, AND stop. Best speed mod for the money, brakes wise, imho.

Good luck, and I hope it turns out well this time.

thanks alot that helps very much and answered more than i needed but is very helpful and makes me think of what is actually wrong. i am thinking that the last time a lubed everything that it is still sticking on the guides. that is the only wheel that gets very hot while driving normal. so i will investigate whats up with it after i replace the lines for ss lines. i have been wanting them for a while just need to go ahead and get them.