Resolved Brakes locking up need help!

[97GSXBOOSTIN]

Ok, so my car sat for about two weeks whe I was installing a new clutch. After getting I together I take it for a ride and around a mile into it the brake pedal gets really stiff and the brakes begin to drag. The longer I drive the worse it gets and eventually they lock up solid and will not move.

I got it home and replaced the front calipers and lines, bled it and it did the same thing. I reaced the master and it still does it. The pedal stays hard now, there is about a half inch play when it is cold, after that it is completely stiff. When quickly checking the wheels, they are all very hot, as if all four wheels are locked up.

I don't know where to go, please help me, I can't keep throwing parts at it, and I am completely in the dark, thanks

 

[Dsmkauai]

Sounds like a problem with the master cyl!

 

[97GSXBOOSTIN]

that's what I originally though, I just replaced it and the issue didn't change at all

 

[jimsgsx]

Let your car sit for a bit then drive it around your block if you can. Then feel the calipers on each wheel with your hand. The hot one is the one causing this. Hope this fixes your problem.[DOUBLEPOST=1412770569][/DOUBLEPOST]Also how is your power steering fluid levels and pump? Could affect it also i believe. Maybe fluid contamination too. Flush it all out with new fluid. I did a little research could be a part called a junction box. And even new mc could be bad.

 

[pauleyman]

Did the pressure release when you had the master off?

 

[SrKegler]

I've ran into the problem before, just not on a DSM. I replaced the master cylinder on an old ford and the brakes would lock up after driving a while. Finally found out the push rod from the brake pedal to the master cylinder was too long. Since your problem is effecting all wheels that may be your problem. Something isn't letting the fluid back into the master cylinder.

 

[97GSXBOOSTIN]

Did the pressure release when you had the master off?

Yes, the pressure did release when I removed the master, also when bleeding.[DOUBLEPOST=1412772961][/DOUBLEPOST]

Let your car sit for a bit then drive it around your block if you can. Then feel the calipers on each wheel with your hand. The hot one is the one causing this. Hope this fixes your problem.[DOUBLEPOST=1412770569][/DOUBLEPOST]Also how is your power steering fluid levels and pump? Could affect it also i believe. Maybe fluid contamination too. Flush it all out with new fluid. I did a little research could be a part called a junction box. And even new mc could be bad.

I did this and it is too close to tell, the all seem to be way too hot.

 

[thejollyrancher]

Sounds like you adjusted the brake push rod by mistake instead of adjusting the clutch.

 

[pauleyman]

Bingo. I think we have a winner

 

[97GSXBOOSTIN]

Sounds like you adjusted the brake push rod by mistake instead of adjusting the clutch.

I kinda hope that isn't case bc i will feel really dumb, but that would be a pretty easy fix! Ill give it a try when I get home. thanks[DOUBLEPOST=1412774301][/DOUBLEPOST]

Sounds like you adjusted the brake push rod by mistake instead of adjusting the clutch.

If that were the case, why would they be locking up and over heating? Is it adjusted so far out that it is causing the brakes to be engaged at all times?

 

[thejollyrancher]

You got it. if you adjust the push rod too tight then the resting position of the rod is already displacing a bunch of fliud and is engaging your brakes. This usually gets worse, i.e. as you drive the brakes get tighter

 

[97GSXBOOSTIN]

So I checked the rod and adjusted it both ways and it wasn't that. the pedal gets hard as a rock around a half inch down, the fluid level is remaining the same also

 

[thejollyrancher]

Since this happened right after a clutch change I cant imagine it being much else. Make sure you really are adjusting the brake push rod, its easy to get the two mixed up as the pedal assembly makes a 90 degree turn about 3/4 of the way up the pedal if I remember correctly. You want to do a full rotation clockwise and see if its changed anything, then another. Keep going until the pedal is effected. And make sure you mark the current position if it ends up being the case that that isnt the issue, then you can reset it to the same position. The push rod adjustment, even if its not the problem, should effect the pedal stiffness. If it doesn't after you recheck it, maybe its a bad brake master. Since its effecting all the brakes thats all i can think of.

 

[2slow4now]

Sounds like the master cylinder is the problem if its not the adjustment.

The internal pistons probably aren't returning back like they are suppose to. Maybe the seals are bad or some dirt is in the master cylinder hanging up the piston or possibly it is just bad. Since the master is holding some pressure on the calipers from a stuck piston, after a little bit of driving it is building enough heat to boil the fluid in the calipers which builds more pressure and applying progressively more brake.

 

[97GSXBOOSTIN]

I'll give it another try when I get home today, i'm almost 100% that it isn't the adjustment rod. It is possible that the new master that i put in could be bad from the parts store.

 

[thejollyrancher]

Wasn't it happening before you changed your master though?

 

[SrKegler]

If the rod isn't keeping pressure on the piston in the master cylinder, the only other thing I can think of is the proportioning valve. Can't believe that would affect all 4 wheels though.

I would crack the bleeder valves on all 4 wheels to relieve pressure, then adjust the rod in the master cylinder all the way out and see if that solves the problem. Tried using search for an old post I remember from years ago where the same problem occurred. Couldn't find it. I believe in that case the new master cylinder rod was too long. Replacing the new rod with the old one solved the problem.

 

[97GSXBOOSTIN]

If the rod isn't keeping pressure on the piston in the master cylinder, the only other thing I can think of is the proportioning valve. Can't believe that would affect all 4 wheels though.

I would crack the bleeder valves on all 4 wheels to relieve pressure, then adjust the rod in the master cylinder all the way out and see if that solves the problem. Tried using search for an old post I remember from years ago where the same problem occurred. Couldn't find it. I believe in that case the new master cylinder rod was too long. Replacing the new rod with the old one solved the problem.

thank you, ill see if swapping the master cylinder rods helps

 

[pearl4gtsi]

When you installed the master cylinder... Did you bleed the master by itself before bleeding the calipers? It is possible for air to be trapped in there, maybe expanding where getting warmed up and applying pressure on the fluid to the calipers?? Just a thought.

And does the brake pedal feel like a rock the whole time? If it does, I'd check the brake booster, although I can't see that causing all 4 calipers to be very hot and locking completely.

 

[ACM]

There are ports above each piston that link to the reservoir; these ports feed fluid into each circuit as the pads wear, and also offer an escape route for expanding brake fluid as it heats up. These ports are only open when the master cylinder pistons are all the way back - the ports are closed off as soon as the pistons move any amount at all. There are springs inside the m/cyl that push the pistons back up against the circlip at the end where the rod fits to keep these ports open.

Your problem is that one or more port is blocked off, so the when the fluid expands in situ the only movable parts are the caliper pistons, so they are forced out of their bores and that causes the brakes to engage.

The most common cause of blockage is that the brake push rod is adjusted too long - this forces the pistons off their seat and that covers the ports over. Shorten the rod until you can spin the connecting pin easily with your fingers, and then shorten it half a turn more (this is how you adjust the clutch pedal as well).

Second cause is that debris is blocking a port off - clean the debris out.

 

[97GSXBOOSTIN]

There are ports above each piston that link to the reservoir; these ports feed fluid into each circuit as the pads wear, and also offer an escape route for expanding brake fluid as it heats up. These ports are only open when the master cylinder pistons are all the way back - the ports are closed off as soon as the pistons move any amount at all. There are springs inside the m/cyl that push the pistons back up against the circlip at the end where the rod fits to keep these ports open.

Your problem is that one or more port is blocked off, so the when the fluid expands in situ the only movable parts are the caliper pistons, so they are forced out of their bores and that causes the brakes to engage.

The most common cause of blockage is that the brake push rod is adjusted too long - this forces the pistons off their seat and that covers the ports over. Shorten the rod until you can spin the connecting pin easily with your fingers, and then shorten it half a turn more (this is how you adjust the clutch pedal as well).

Second cause is that debris is blocking a port off - clean the debris out.

do i spin the rod clockwise or counter. thank you for the info[DOUBLEPOST=1413221786][/DOUBLEPOST]also, do I need to crack the bleeders to adjust the rod?

 

[thejollyrancher]

Counter Clockwise. I just realized I wrote clockwise in my above post. Sorry I hope I didnt mess you up, just got confused trying to picture which way it was going while hanging upside down in my car. No you do not need to crack the bleeders

 

[SrKegler]

Clockwise to shorten the rod.

 

[97GSXBOOSTIN]

I can't believe it, but that was it. I adjusted the pedal rod out and the brakes are perfect. Also, correctly adjusted my clutch while i was down there and that is shifting perfect now too. Thanks for everyone's help!