What's up with my brakes!!!

Jeeper99

Jeeper99

New member
Ok, When I first got my TJ, I noticed after it set overnight, I would get in to go to work the next morning and when I would stop at the end of my driveway, the back brakes would practically lock up. But only at slow speeds. It was fine after I went down the road and stopped at a couple of red lights. Figured it was the wheel cylinders locking up. I finally got a chance and put new shoes in the back, Had the Drums turned and a new brake kit, springs, wheel cylinders....etc. Didn't have a problem with them locking up anymore.

Now, I was back behind the house today while it was raining and went to slow down fairly quickly and my front wheels grabbed and just slid and felt like my back wheels were not braking any at all. I know the fronts are disk and the rears are drum, but dang!!! I'm kind of wondering what's going to happen if we get a little snow and slick roads this winter! has anyone had this problem and is there a way to fix it besides the big task and cost of a disc conversion in the back? I know the front is supposed to have something like a 60% braking and back is 40%, but this is ridiculous! i've also pondered on putting a 50/50 proportion valve on my TJ that came out of our 97 Grand. Just to mainly get some more braking power to the rear. Any thoughts or advice, please help! :?|
 

Have you tried bleeding the entire brakeing system? You may have air in the lines.
 
The problems sound unrelated and pretty typical.

The first incident sounds like common rust that forms on brakes after they sit a while, they're very touchy until the surface rust wears off after a little use.

The second incident sounds like the rear brakes may be out of adjustment, very common. The brake shoes are supposed to adjust closer to the drums each time you back up and apply the brakes. The adjuster inside the drum often freezes up and doesn't operate properly. I'd suggest adjusting the rear shoes by removing the rubber plug in the backing plate and spinning the star-wheel adjuster until you feel the drums dragging. Then back it off slightly.
 

I had the same problem on my CJ. Like Bounty said, adjust the rear shoes, it worked for me.
 
believe it or not, I did that also. I first got them just a little too tight and went around the block in the neighborhood for a test while they were tighter and they still did the same thing. I drove approximatly 1/4 mile at about 15 mph and when I got back to my garage, the wheels where Hot. so I backed them back off slightly. I will check them again and see if I can find anything out. Thanks Guys!!! Keep throwing any other ideas out there, I need all the help I can get before the snow starts falling, or I'll be in a ditch with some dirty briches.
 
Have you tried pulling the master cylinder apart, and clean it up with some brake cleaner. There could be something clogging the rear line feed.
 

JJs 88 Wrangler said:
Have you tried pulling the master cylinder apart, and clean it up with some brake cleaner. There could be something clogging the rear line feed.
Click to expand...


Just put a new one on it about 4 months ago. Actually changed that first, then done the rear wheel kit, then bled the whole system twice, with no change.

Just a stupid question to throw out there, but if I jack the back end up, how is the best way to "Recheck" the brake adjustment on the rear? Just tighten it until there is very slight drag on the rear wheels as it's rolling freely? That's what I did before, but there was still no change.
 
This is how i adjust the Rear Shoes on my CJ. Raise the Rear axle and support it with a jackstand, pull the rubber plugs behind the Drum Plate, while moving the wheel with one hand back and forth ,adjust the sprocket till it snugs to the drum. after doing the same to the other side, engage the E-Brake all the way. this will make sure that the Shoes inside the drum centers and equalizes. release the Brake then re-check the adjustment.Re-adjust as needed.
 

well, unfortunatley, I tightened up the rear brake stars today with no change. The front is still sliding.... anybody else have any more ideas.
 
sounds to me like your combination valve my be malfunctioning. most modern cars with front disc/rear drum dual circuit brake systems have one valve body that has three functions: the proportioning valve you mentioned, the DELAY VALVE which prevents the front disc brakes from grabbing before the rear drums have a chance to start braking. and the brake failure warning light switch. i don't have a service manual for your vehicle, but that's where i would start. also, i can't stress the importance of following the manufacturer's instructions on brake adjustment EXACTLY!!! every other system on the vehicle we can monkey around with. but when it comes to the braking system, we have to make absolutely certain the work is done correctly. good luck, john
 
I wonder if the shoes might not be arched to the drums correctly. I had a set on an old truck like that - they never worked until they "wore in" a little. Here's a good test for shoe arch... Roll forward slowly (like 1-2 MPH) and pull up on the emergency brake - The rear wheels should lock. If they don't then I would question the shoe arch OR assembly of parts. And, one simple hydraulic test... secure the rear end up on jackstands, have someone turn the wheels by hand and you push the brake pedal lightly with your hand. You should be able to stop the wheels with no force at all on the pedal. Best of luck - John
 

Crazy4diesels said:
I wonder if the shoes might not be arched to the drums correctly. I had a set on an old truck like that - they never worked until they "wore in" a little. Here's a good test for shoe arch... Roll forward slowly (like 1-2 MPH) and pull up on the emergency brake - The rear wheels should lock. If they don't then I would question the shoe arch OR assembly of parts. And, one simple hydraulic test... secure the rear end up on jackstands, have someone turn the wheels by hand and you push the brake pedal lightly with your hand. You should be able to stop the wheels with no force at all on the pedal. Best of luck - John
Click to expand...


I pulled the E-Brake to see if they would lock and it didn't. It took 2-3 ft ft to stop.... :???: :?| :???: I still don't really know how to go about fixing this. It's Really not that big of a deal I don't guess, but I would hate to be on a slick snow/mud road and go to hit the brakes and the front end just lock up and off in the ditch I go. :roll:
 
i would consider looking into the proportioning Valve . sounds like the limiting valve spring is releasing exessive pressure towards the front circuit. were there any signs of fluid contamination?, if so, i would consider replacing the front brake hoses on the calipers as well. Bleed them well.
 
SteelHeadz said:
i would consider looking into the proportioning Valve . sounds like the limiting valve spring is releasing exessive pressure towards the front circuit. were there any signs of fluid contamination?, if so, i would consider replacing the front brake hoses on the calipers as well. Bleed them well.
Click to expand...

nope, the fluid looked fine and then was replaced and bled a few times after the new master cylinder was installed. I actually took the 50/50 proportioning valve off our wrecked 97 Grand to try if all else fails. The limiting spring you are talking about, is it accessible or would I just have to buy a new factory spec valve? Thanks for the help
 

While following this post......has all this braking stuff happened on non-pavement surfaces?? (ie: grass (wet), dirt, gravel) Does your Jeep have ABS?? I have issues whenever stopping off-pavement with any d#*# ABS vehicle. Personally, I'd rather lock 'em up than have some computer keep me from doing it (when needed). Just a thought. Your brakes might be fine, it may just be the ABS.....and there are ways of bypassing it.

Keep us posted.

Clueless but tryin' to help,
Slippin' and slidin' mud
 
nope, mine don't have any ABS. Our old 97 Grand did and it scared the crap out of me when it would kick in. Felt like the brake pedal was gonna explode with the vibrating and shaking when the ABS kicked in. With my wrangler, it just locks up. Mainly off road, but it has done it on wet rain soaked roads which made me stain my briches.

The first time I noticed, I was backing my small boat down the ramp at the lake and was holding the brake, the front tires just locked up and I almost jack-knifed my trailer and just about hit another vehicle and people on the ramp. Luckily, I was quick enough to grab the E-brake, which did stop me.
 
Hey there Jeeper99,
If you were going about 2 MPH and pulled the ebrake up you should lock the rear wheels... If it took a few feet to stop I would guess there is a shoe or assembly problem (unless your ebrake cable is not adjusted right... If your handle comes way up you might need to tighten it up a little). Try the other test if you have time (the jackstand-push-the-pedal-by-hand-test) and Let us know what happens. Best of luck - John
 

unfortunately from the factory side, it's serviced as aunit. there might be aftermarket outfits there that may have just the valve. just a guess.
 
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