I have a 1991 XJ w/O ABS. I have changed the brakes both front and rear, changed the brake booster and the master cylinder. I can NOT make an emergency stop and lock up the wheels. normal driving around is ok, but if a child or dog runs out in front of me, or someone stops fast in front of me, I will hit them. I can not lock up the wheels. is this normal for the older XJ's ? when I push hard on the peddle it feels like it just won't go anymore down and the car stops fast, but with the amount of pressure I am putting on the brake peddle the tires should be skidding....anyone also notice this or have a solution ? thanks in advance for any ideas...

 

If the pedal doesn't sink to the floor, if it stays high & feels hard, could be either;

Pinched lines
Or
Clogged/corroded lines;
Have someone put pressure on the brake pedal while you open then close each of the bleeder stems one by one. Each time you open a bleeder, the pedal should sink quickly and smoothly to the floor, and you should get a steady stream of fluid till the pedal stops. You'll get less fluid from the rear drums than the front discs, this is normal. An empty soda bottle and rubber tubing will keep this from getting messy.

Corrosion in the master cylinder;
Install a bench bleed tube kit, and cycle the pedal slowly, not all the way to the floor, just 4-5 inches. It should cycle back and forth smoothly, and after a few cycles, you shouldn't get anymore bubbles in the tubes.

Bad power brake booster;
Test drive the jeep. Then with a set of needlenose visegrips, pinch the vac hose leading to the booster shut. Drive it again. If the brakes feel the same, or you notice the engine running much smoother, you've got a bad booster.

Hope this helps.

 

Twisted Wrench: Excellent replies

I would also have someone look under the Jeep while you push down on the brake pedal and see if any of the flex lines are "ballooning". I had this happen on an Astro van that would pull to one side when brakes were applied. One of the flex lines would do this and the braking would be uneven. Couldn't see it until I had a buddy helping with bleeders and his head was right in front of the line so he could see it.

 

Ever adjust the rear brake shoes?

 

Problem start after you changed the brakes, or was the brake work an attempt to fix it?

 

x2...

 

Well good comments guys. I have a brand new master cylinder and all new flex brake lines. When I bleed the brakes I get good strong streams of fluid at all wheels. This has been a problem since I got my jeep 5 years ago.also I have a new brake booster. Just won't skid the wheels or make an emergency stop. Normal driving is ok and fast stops can be done. But like I said, of I have to lock em' up for some reason...no way....

 

Have you adjusted the rear shoes?

Are the front calipers on upside down?

 

Well I have a new brake booster and new master cylinder. When I bleed the brakes I get good strong stream at all wheels.....thanks for your suggestions. It's like there just isn't enough pressure on the rear brake shoes or not enough grab power on the front pads. Really strange.

 

Ahem......

 

Well I have a new booster, master cylinder, new flex lines....still not enough pressure to lock em'm up.

 

Oh yes, I have adjusted the rear shoes and replaced the shoes and all the hardware. As far as the front calipers go, I don't know what you mean about them being up side down. They are where the always have been. Thanks

 

No this has been a problem for the past 5 years when I bought the old girl.

 

Are you running oversize tires?

 

Upgrade booster..older xj brakes way under powered .