Break problems

[greencj5]

I just got my CJ back on the road after 10 years in the garage. It runs fine but I'm having brake issues. I've replaced the rear wheel cylinders and pads. I've also bled the brakes a couple times. My issue: after driving around the block several times, the brakes ( I think) are locking up. Slowly not all at once. The more I drive, the more they begin to lock up. If I don't get back to the barn in time, I'm stuck. The first time I needed a tow home. I've since realized that if I let the vehicle sit for a time, the pressure releases and I'm good to go.

Any suggestions on where to begin would be appreciated.

 

[Old Dog]

My guess would be either you have the back brakes adjusted to tight and they are heating up and draging or your proportioning valve is hanging up and making them lock up.

 

[BusaDave9]

Drive the jeep around untill the brakes drag. Jack up each corner and check what tire has the brakes locking up.

 

[greencj5]

Old dog- the lockup problem did existing prior to the back wheel brake work. Any idea if the proportioning valve is servicable or only replaceable?

 

[BusaDave9]

My guess would be either you have the back brakes adjusted to tight and they are heating up and dragging

Old dog- the lockup problem did existing prior to the back wheel brake work. Any idea if the proportioning valve is serviceable or only replaceable?

I'm with Old Dog, check your brake adjustment. It still sounds very possible.
The proportioning valve is not servicable but I don't think that's your problem.

 

[Old Dog]

You never really told us which brake is hanging up, front or rear. I just <-BAD WORD->- sumed it was the rear.

I had a car one time that the front caliper would hang up and keep getting worse as it got hot till it would lock up the wheel. New caliper and all was good.

 

[greencj5]

still having brake issues. Left front brake locks up after driving around the block a few times. the right front spins free. wondering if its the proportioning valve. seems like the most probable thing.........

 

[oldguy]

I agree with Old Dog, replace the caliper. It's most likely that the pistons inside arn't releasing as fast as they should. No return springs there... Also I've never seen a proportinonig valve go where it caused brake lock up. Just MHO

 

[BusaDave9]

I agree with oldguy. A propotioning valve wont cause this. Especially one wheel locking up.

Are we sure it's not the wheel bearings?

 

[Torxhead]

Flexible brake lines swell up on the inside also, and can block off releasing brake fluid.

 

[tarry99]

I just got my CJ back on the road after 10 years in the garage. It runs fine but I'm having brake issues. I've replaced the rear wheel cylinders and pads. I've also bled the brakes a couple times. My issue: after driving around the block several times, the brakes ( I think) are locking up. Slowly not all at once. The more I drive, the more they begin to lock up. If I don't get back to the barn in time, I'm stuck. The first time I needed a tow home. I've since realized that if I let the vehicle sit for a time, the pressure releases and I'm good to go.

Any suggestions on where to begin would be appreciated.

I agree as others have stated change the caliper, but I would add to that since its been in storage for 10 years most likely the calipers are rusted inside the piston walls I would change them both, as its just a matter of time for the other side, likewise I would also drain and replace the fluid in the brake system it can get moisture in it over that period of time.

 

[jamie]

did this jeep start off life with a drum drum configuration? the reason i ask is i just went through this, and i needed to replace the master cylinder from a drum drum to a disk drum. the fluid wouldnt return fast enough and the front brakes would lock up if i drove it enough