hillbilly51 Posted August 24, 2014 Share Posted August 24, 2014 I recently replaced the rear brakes and rear parking brake cables on my 88 Comanche Chief. I adjusted the rear brakes and then tightened the center parking brake cable cable..the main one from the pedal...until it was pretty tight. I jacked the rear wheels off the ground so that I could spin them by hand, and tightened the brake cable in steps. After each adjustment, I would make sure that the brake shoes weren't dragging. I tightened the cable until I had the parking brake pedal adjusted so that it would travel almost to the bottom of it's stroke without hitting the floorboard, and the wheels would still spin freely (slight drag) with the parking brake released. I live on a pretty steep hill, and my test of the parking brake was to pull part way up the hill, put the transmission out of gear, push the parking brake pedal down as far as it would travel and then release the brakes. The parking brake will not hold the truck, and allows it to roll backwards. I'm definitely getting some braking action, but I would expect the parking brake to hold the truck stationary. Do I need to tighten the cable more, or is this the nature of the beast. I'm afraid that I will break the front parking brake cable if I tighten it anymore. I'm already putting a lot of force on it with the adjustment that I have now. How well does your parking brake hold? All response is appreciated steve Link to comment Share on other sites More sharing options...
yxmj Posted August 24, 2014 Share Posted August 24, 2014 The brake should hold the truck even on a slight incline. I do not know the grade of the hill you tested on buy it should hold as if you had your foot on the brake. The parking brake is adjusted by lengthening the adjuster screw/bolt in the brake assembly #12 ( I usually turn it out till you can just fit the drum on) It should I believe self adjust.....pump your brakes numerous times and try again Link to comment Share on other sites More sharing options...
Jeep Driver Posted August 24, 2014 Share Posted August 24, 2014 Adjust your shoes out before final adjustment on parking brake cables. You will break your front cable, I did. Replace it. Parking brakes should lock your rear wheels regardless on incline. Pedal should bottom out about 3/4 of the way to the floor. Link to comment Share on other sites More sharing options...
hillbilly51 Posted August 24, 2014 Author Share Posted August 24, 2014 "You will break your front cable, I did" Me too...... "Replace it.".... Got one ordered..... "Parking brakes should lock your rear wheels regardless on incline" Then I need to tighten up the adjustment on the new rear brake shoes. I adjusted the shoes when I put the new ones on, the drums were pretty snug at that point. I then used a brake spoon to further adjust them (with the rear wheels up in the air). I adjusted them until I got some drag. I've done a lot of drum brakes in the past, and I thought I had them run out far enough. I did all of this before I tightened the front parking brake cable. "Pedal should bottom out about 3/4 of the way to the floor" It would go almost to the floor before I broke the cable. I replaced the rear cables with new ones. It's possible that the old cable was weak. It broke at the pedal attachment. thanks steve Link to comment Share on other sites More sharing options...
Eagle Posted August 24, 2014 Share Posted August 24, 2014 The parking brake will not hold the truck, and allows it to roll backwards. It won't hold because that's the design. Try it heading forward down the hill. The drum brakes on the MJ are what used to be called "servo assisted" brakes. The reason for the unequal length shoes and for some of the other hardware inside is to allow the brakes, once applied so the shoes contact the drums, to use the friction to rotate the shoes and jam them tighter against the drums for more stopping power. But ... it only works going forward. That's just the nature of the beast. Part number 12 in yjxj's exploded diagram is NOT the parking brake adjuster. It's the primary brake adjuster, and should be adjusted with the parking brake cables backed off and slack. Adjust the shoes just to the point of slight drag, then back off two clicks on the star wheel. The factory manual says to perform a final adjustment by doing five hard stops when going in reverse. THEN you adjust the parking brake cable. The FSM calls for using a special tool to check the tension in the forward cable, ahead of the splitter. For the rest of us, the brake should be adjusted so that it will hold the vehicle when headed forward on a moderate downgrade (say 5 percent to 7 percent). Don't even try to make it hold when parking headed uphill ... you'll just break (not brake) something. Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 25, 2014 Share Posted August 25, 2014 Man, I so glad I got rid of the POS rear drums years ago. My parking brake holds on a 45* hill facing up or down. Link to comment Share on other sites More sharing options...
Jeep Driver Posted August 25, 2014 Share Posted August 25, 2014 Never had a problem with my truck staying put on hills......all we got are hills. Link to comment Share on other sites More sharing options...
Roost426 Posted August 25, 2014 Share Posted August 25, 2014 Mine doesn't work good at all either, i just find a rock/block of wood nearby and stuff it under a tire if I have to be parked on a steep incline. Link to comment Share on other sites More sharing options...
hillbilly51 Posted August 25, 2014 Author Share Posted August 25, 2014 I guess I should have quit while I was ahead. I followed the procedure and had what I now suspect was a OK parking brake. I'll put the new cable on and try again....this time going down hill. thanks everyone steve Link to comment Share on other sites More sharing options...
big66440 Posted August 28, 2014 Share Posted August 28, 2014 just buy some wheel chocks, GUARANTEED to stay put :thumbsup: Link to comment Share on other sites More sharing options...
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