kd5dwy
NAXJA Forum User
- Location
- Central Arkansas
I know this has been beaten to death, but I thought I'd post my brake problems here and what I'm doing to resolve them. If you are having problems with your brakes/booster/master cylinder, I hope this helps.
First of all, I have an 87 XJ almost stock (completely stock in the brakes department). When I bought it, the brakes were spongy and the brake light was lit. When depressing the brake pedal, I would hear a constant shhhhhhhhhhh sound from under the dash.
The first thing I did was replace the brakes. Fronts are very easy to do and I believe that process is covered in other posts on this site. There are two different versions of pads for the Cherokees, so take your old pads in once you get them off and make sure everything matches from old to new. I tried to be prepared and picked up a set of pads ahead of time only to find out I had the wrong ones. These ended up costing just over $30 for both sides. The old pads were completely gone and the rivets that hold the pad material on had dug into the rotor about 1/8". I had to pick up new rotors which ran about another $35 for both sides. Both wheels took under two hours.
The rear drum shoes aren't too bad if you've done any break work before. I highly recommend getting a retainer spring tool from the auto parts store (they're about $5 and relieve about $50 worth of frustration). New brake shoes ran about $30 for both wheels. Both wheels took about three hours (including cleaning everything up with a wire brush). Make sure you lube the brake adjuster assembly with a bit of grease while you're swapping all the parts around. The Haynes manual was very handy to have on hand for the rear brakes.
After getting everything adjusted and bled, the Jeep stopped much better and the light went out occasionally.
I could pump up the brakes, hit them hard and come to a very quick stop. I still heard the shhhhhhhhhh from under the dash and the system would still lose pressure causing the brake light to come back on occasionally, but I could pump up the system and the light would go off.
I was afraid that I was losing fluid from one of the calipers (front) or wheel cylinders (rear), but after careful inspection, I don't believe that to be the case. Also, the fluid level in my master cylinder is not dropping.
I did notice that with the cover off of the master cylinder, brake fluid seems to escape from the piston when the brake pedal is pressed. I'm not sure if this is normal, but I don't think it's supposed to do that.
After a bit of research, I believe the shhhhhh from under the dash is a bad brake booster. With the brakes losing pressure and the fluid escaping the cylinder, I figured my master cylinder is bad as well.
I removed the old master cylinder and brake booster (I had to take off the window washer fluid reservoir to get to everything). I was expecting this to take quite a bit of time, but it only took about an hour and 15 minutes doing all of the work by myself. I just picked up a new booster and master cylinder (about $100) and will be installing it this weekend. I'll give an update after it's in.
If this doesn't do the trick, I think I'll move on to the proportioning valve, wheel cylinders and calipers.
First of all, I have an 87 XJ almost stock (completely stock in the brakes department). When I bought it, the brakes were spongy and the brake light was lit. When depressing the brake pedal, I would hear a constant shhhhhhhhhhh sound from under the dash.
The first thing I did was replace the brakes. Fronts are very easy to do and I believe that process is covered in other posts on this site. There are two different versions of pads for the Cherokees, so take your old pads in once you get them off and make sure everything matches from old to new. I tried to be prepared and picked up a set of pads ahead of time only to find out I had the wrong ones. These ended up costing just over $30 for both sides. The old pads were completely gone and the rivets that hold the pad material on had dug into the rotor about 1/8". I had to pick up new rotors which ran about another $35 for both sides. Both wheels took under two hours.
The rear drum shoes aren't too bad if you've done any break work before. I highly recommend getting a retainer spring tool from the auto parts store (they're about $5 and relieve about $50 worth of frustration). New brake shoes ran about $30 for both wheels. Both wheels took about three hours (including cleaning everything up with a wire brush). Make sure you lube the brake adjuster assembly with a bit of grease while you're swapping all the parts around. The Haynes manual was very handy to have on hand for the rear brakes.
After getting everything adjusted and bled, the Jeep stopped much better and the light went out occasionally.
I could pump up the brakes, hit them hard and come to a very quick stop. I still heard the shhhhhhhhhh from under the dash and the system would still lose pressure causing the brake light to come back on occasionally, but I could pump up the system and the light would go off.
I was afraid that I was losing fluid from one of the calipers (front) or wheel cylinders (rear), but after careful inspection, I don't believe that to be the case. Also, the fluid level in my master cylinder is not dropping.
I did notice that with the cover off of the master cylinder, brake fluid seems to escape from the piston when the brake pedal is pressed. I'm not sure if this is normal, but I don't think it's supposed to do that.
After a bit of research, I believe the shhhhhh from under the dash is a bad brake booster. With the brakes losing pressure and the fluid escaping the cylinder, I figured my master cylinder is bad as well.
I removed the old master cylinder and brake booster (I had to take off the window washer fluid reservoir to get to everything). I was expecting this to take quite a bit of time, but it only took about an hour and 15 minutes doing all of the work by myself. I just picked up a new booster and master cylinder (about $100) and will be installing it this weekend. I'll give an update after it's in.
If this doesn't do the trick, I think I'll move on to the proportioning valve, wheel cylinders and calipers.