brakes lock up after driving

[Chris111]

new master cylindernew brake booster

the brakes get tight after a few minutes of driving. so i changed the master and the brake booster hoping that it would fix the problem but it didnt'. you can bleed the brakes and they roll free but after a few minutes they just get tight and tighter again. i'm really stumped on this and i can't figure it out. i'm changing the lines and the calipers will be after that if the lines dont fix the problem. what else could it be and whats left? anything i'm missing?

thanks, chris

[bangstanger]

It truly sounds like the lines...when you pressurize them they work..but are collapsed inside so they cant relieve the pressure. Very common and hard to find. The other thing you can check is the slides and hardware on the caliper to make sure everything is moving smoothly. A check of the pad wear should tell you if there is a problem with the calipers or slides. IE uneven wear mainly on the inboard pad for caliper and out for slides..(not always true..but close)

[Chris111]

yeah thats what i figured. i'm about to order some ss spl lines. i'm sure that you know about these? any opinions on them. i've been reading some good things about them and i just want to get a good product for my car. i always want to do things right if i'm going to do them. the pads are brand new so i can't see any wear yet.

thanks for responding so fast, chris

[bangstanger]

Yeah I dont have any personal experience with them .. but I havent heard anything bad. No prob. Good luck.

Carl

[Chris111]

yeah i just ordered them a few minutes after i posted. i'm excited to get my car on the road once they arive.

Chris

[180fan]

Sounds like you need to put brake grease on the caliper pins. Not new lines, although they'd be nice (but probably not the source of your problems).

[Chris111]

so your saying once they get hot they are expanding enough to make them stick? i'll try it in a few minutes.

if the car sits for a few hours after they lock up, the pressure is realeased and the car will roll. thats why i think it's lines but i'll deff. be trying your idea.

anymore ideas?

thanks, Chris

[180fan]

yep you betcha. I'm very certain it's your pins.

[Chris111]

if the pins were not lubed wouldn't they just stick instantly? it wouldn't make any sense because the pressure releases when you crack the bleeder valve or let it sit for a few hours. i never got a chance to try that today but i'll be doing so tomorrow hopefully. it's worth a try until i get my lines here.

Chris

[navysnail]

its probobly a case of the pins sliding very slowly, so once you hit the brakes a few times, it is able to move the pins out (engaging outside pad, like its designed to) but they dont slide back, or they slide once again, very slowly. when you grease them, make sure you use synthetic caliper grease, as normal grease will not tolerate the high temperatures it would be exposed to

[Chris111]

well i just got the lines and i dont have them all in so i haven't tested it but i took the right rear pins out and they were clean lubed well. i'm completely lost.

[navysnail]

how about the fronts?

[Chris111]

Well I just finished cleaning the calipers and putting the new spl lines in. I checked the caliper pins since everyone was pretty sure that was the problem. The rear caliper pins looked like they were lubed pretty well and they didnt' have any build up on them either. I still cleaned them with brake cleaner and relubed them anyways. Now the front caliper pins were lubed also but the top pin was a little dry on the driverside and had some build up (kinda like gunked grease), again I cleaned them all and relubed them. Since I had the calipers off I figured I would check the condition of them. I noticed that the driver side piston didn't push in freely like the passenger side did. I was told that they push in easily. Tomorrow i'm bleeding the brakes and hoping for the best. I begining to think that lubing the pins isn't going to solve the problem since all the pins were lubed well except the top driver side.

any input?

[180fan]

Give it a try first. All it takes is one caliper to lock up for you to get shafted. The pins are all supposed to slide in and out very easily. Only other thing I can think of if it's not the pins could be rust around the pistons gripping the side of the caliper. How long have you had that brake fluid in the car? Do you live in a high moisture area, etc?

[Chris111]

I'm going to try it out today because I couldn't bleed them alone. The brake fluid is about 4 days old now? lol. I guess i'm going to buy new calipers after this if it doesn't work.

[Chris111]

It's fixed!!!!!!! Turns out that the rod that goes into the master cylinder was adjusted wrong so I readjusted it and the problem went away. now i get to spend some money on things other than getting the brakes to work haha.

thanks for all of your help guys, Chris

[bangstanger]

Glad to hear it...sorry we couldnt figure it out for ya sooner ..

Carl