My brakes work fine to arrest forward momentum... excellent, actually. The issue I'm having is rearward momentum. They refuse to keep my XJ from rolling backwards when stopped on an incline of more than a few degrees. The pedal pressure is the same as when moving forward and it seems to be holding pressure just fine, they just don't work to stop me from rolling backwards.

The pads and shoes appear to have about 75% remaining and under panic braking both the front and rear will lock (non-anti-lock). Also, my parking brake is tight and will lock the rear tires when moving forward but does virtually nothing to arrest rearward movement.

Ideas?

 

Most drum brakes have a large shoe in front and a small shoe in back. It's designed this way to provide maximum stopping power in the forward direction, so naturally, it won't be as effective in reverse. This might be different with the XJ, I'm not positive as i haven't had to tear apart my rear brakes yet, but it was common in every other drum braked vehicle I've owned.

BUT, you should be able to hold the vehicle still while in reverse. The front brakes should be able to handle this as well.

My feeling is that your rear brakes are:

A) Out of adjustment
B) Installed incorrectly (make sure the large shoes are toward the front of the vehicle)
C) Leaking. Maybe the wheel cylinders are bad, maybe the brake line is leaking.

Still, you said the emergency brake isn't holding, so I'm guessing they're just out of adjustment.

 

More then likely the first two would be the problem. If it was a leaking cylinder you would also have problems stopping in forward gears too.

 

Thanks both for your suggestions. I haven't pulled the drums which would obviously be the primary brake when my XJs mass is trying to move backwards but I'm still a bit puzzled at why the fronts won't even lock. It's as if the friction material only bites in one direction. Perhaps I should just toss these pads and shoes and start over with a fresh set that can be properly bedded. There's a decent glaze on the front rotors so they could use to be turned, anyway. I'm sure the drums aren't much different.

I've owned two cars with rear drums and IIRC both used the same size shoe front/rear (of the drum). If they were different it was only slightly, not enough to be readily apparent when just looking at them.

 

P.S. PO is an old lady who probably never went fast enough to actually generate enough heat in the brakes to warm your hands... There's a remote possibility that these are the original pads/shoes. I asked her, she doesn't recall ever having them changed. Yikes.

 

dont know if this helps

my last 2 jeeps .. both manual 5 speeds

parking brake would not hold .. if rear end pointed downhill .. i learned to keep it in gear while parked .. really didnt want to wrench the parking cable too tight .. lever felt fine, tight

other than that braking was fine

 

Having same problem w/ mine! There is an adjustable cable at the rear axle apparently. Holds fine facing forward, but backwards...Fuhgettabout it!! Lol

 

Are you sure fronts are not locked allowing slideing?

 

Yep, I'm sure. The fronts are not locking when trying to prevent rearward motion not matter how hard I push on the pedal.

 

Ever consider upgradeing to double diaphragm booster

 

Not really. I may consider that after replacing the pads and having the rotors/drums turned. I'm also considering something like the Tom Woods TC brake. For now, I'm gonna replace all my lines with braided/Teflon and replace the pads and shoes. I'll let ya know how it goes.

 

The booster up grade increases the pressure your appling to wheels. When applying brakes now most likely you can push pedal pretty close to floor with out and brakeing difference correct?

 

Actually, the pedal feels right, it gets progressively stiffer through about 50% of travel where the pressure requires me to stand on it. I've owned many cars in my life and compared to most I would rate the braking effectiveness on my XJ to be very good with good pedal feel and minimal travel... except when trying to keep it from going backwards. I rate that part as suck.

 

Well if he ain't trolling y'all, it's possible he may have another issue other than the brakes. Of you let go of ya brakes do you roll back. The engine should have enough power to prevent you from rolling back to much. Just a thought. May be right may be wrong but a thought

 

So should my brakes, hence my trolling... er, I mean question.

Just thought maybe someone else had experienced this and might have a solution.