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Brakes locking up

sledneck

NAXJA Forum User
Location
Durango, Co
I just started having a problem...When I break I can slowly push into it, and it seems fine, but I get toward the bottom of the break and before it should the front breaks lock up. Sometimes one before the other. I tookd the tire off and the break caliper all seems fine. Anyone have any ideas?
Thanks
 
All of them at the same time, just the front, just the rear? Could be the perportioning valve in your master cylinder. If so the master will have to replaced as a unit.
 
I did they look pretty good and I cleaned them. I got a master cylinder but are the perportioning valves in the master cylinder or are they on the axle somewhere. I didn't see them on the axle but I don't know what they look like either.
 
FYI, although it is referred to as a proportioning valve, its proper name is "combination valve" as it includes the pressure differential switch for the warning lamp.

Another pit of useless trivia floating around in my head, so I had to share it.
 
Didn't work, it was slightly dirty but not much in there. Put it back in bled the brakes and its still doing it. I dont think a new master cylinder will help anything. Anybody have more ideas?
 
There is not a whole heck of alot that can make your front brakes lock up. The number one problem would be contaminated brake pads/rotors. A bad combo ;) valve would more likely make the rears lock up. It could also be a bad return seal on the calipers, I suppose. Why don't you try to get a new set of pads, and lightly sand down the surface of your rotors in a circular pattern, and see what happens.

Also I assume your brakes are locking then letting go after you get off the pedal? If they are locking up and staying replace your calipers.
 
I don't want to over simplify this, but on my Jeep if the rear drums are way out of adjustment, the fronts lockup as they are trying to carry more of the work.
 
I was pissed and drove in four wheel with the brakes on as hard as I could. I drove after that no more lock up(and yes their unlocking when I let the brake off). I went and got some new pads and I was thinking about geting the rotars turned. I'll check the rears out too thanks.
 
I got it. Not sure what it was but I got new rotars for the front and new pads. Checked the back they were pretty worn so I changed them.

Thanks everyone for your help
 
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