Brake problem

1971 CJ5, 225 V-6, drum brakes all around. My problem is that the jeep pulls to the drivers side when I apply the brake. I changed the pads and wheel cylinders about a year ago. I only use the jeep a few times a year to hunt. I jacked up each wheel seperately and the fronts seem to be working good. The rears are not working at all. I bled the rears but it did no good. Does it sound like the master cylinder? Thanks for any help.

 

#1. Pulling could mean a few of things, contaminated shoes, warped drums, not adjusted evenly, wheel cylinder not working correctly, parts within the wheel not installed correctly,or hanging up. Probably just an adjustment.
#2. Rears not working could be master cylinder, or seized wheel cylinders, I guess if you replaced the wheel cylinders there probably not seized, does the fluid bleed out of rear bleeders? If not pump up brakes and loosen fitting on master cylinder and see if fluid moves out, if not master cylinders bad. If you question the MC just swap it out, it's inexpensive peace of mind.

 

When I bled the rears I got fluid from both rear wheel cylinders. Nothing seemed abnormal.

 

When the fluid moves out it usually means the MC is working. The fluid should be under a decent amount of force, not just oozing out. I guess if the seals were leaking in the MC you might not be getting needed pressure to move the wheel cylinders. I would pull a drum and slowly press the brake and watch the wheel cyl, you should see them moving out (don't let them move too far out just enough to see movement) While you have the drum off peel back the dust boot on the wheel cyl and look at the bore. I've bought new cylinders that had pistons rusted in place, just a thought.

 

you may want to change the flexable line above the rear axle. my rear brakes worked alot better when i changed my 30 year old hose a couple of years ago. 12 bucks well spent

 

I pulled the drum off one side (back) and applied brake pressure and the pads expanded like they were supposed to. When I put the drum on and applied brake pressure I could still spin the drum. It seems like their is pressure going to the wheel cylinder but not enough pressure under a load. Could it be the proportioning valve. Also I took the jeep out and locked up the brakes and there was only a skid from the front left tire. Thanks

 

There are no proportioning valves on these Jeeps, there are residual pressure valves in the MC, possible that one has been removed or not replaced when a MC was replaced.

 

When I jack the rear wheels and spin the wheels and apply the brake the tires initially brake for a second and stops the spinning wheel. After a second the brake looses pressure and I can turn the wheel by hand with the brake applied. I am still thinking that it is the master cylinder. Helppppppp.

 

Well, yes. Looks like you're going to have to pull the master and check it out. I ordered one from NAPA. Good Luck.

 

If that's the problem, it's a fairly easy fix. Replace the cylinder, bleed the brakes, and you're done.

I'd suggest you pull all the drums and inspect the shoes and cylinders for leakage. A bad MC won't make it pull - instead it just won't stop. Also inspect your flex hoses; now would be a good time to change them if they are suspect.

BTW drum brakes don't have pads; they have shoes. Only disk brakes have pads.