Braking Question

[jcwxj]

On my 86 I have replaced everything master cylinder,Power booster, wheel cylinders, pads and shoes and hoses. The brake lines are good no leaks.But the brakes still arent good. Is ther anything else I can check. i seem to have good vacum coming to the booster. Iam lost????

[XJING]

Older XJ's are know for their piss poor performance when it comes to braking, If the brake system is indeed working at its best and your still not happy, you could swap you booster/Master with a Dual Diaphram Unit out of a 95 or 96 XJ, Its pretty much plug and play. It made quite a difference in my rig and a number of others that have done it. Heres one of the many write ups on it. It also has the ZJ rear disk mod there also. Read it and then do a search on all the forums, theres a lot of good info in this subject. Heres the write ups:
http://www.madxj.com/
Good Luck

[90xj06]

could it possibly be that the rod pushing the master cylinder is not long enough.

[old_man]

Do a good vacuum bleed on the system.

[Matthew Currie]

It might be a good idea to try to narow down what is bad about the brakes. As noted, earely XJ brakes aren't anything special to begin with, but they should at least stop you. If you jam them on on gravel, do all 4 lock up? Is the pedal firm, or soft? Can we presume that the booster is good, since you replaced it (i.e. with foot on pedal, start engine, pedal sinks the appropriate distance)?

One suspect might be the proportioning valve. If that's clogged, seized or not working right, it could basically be cutting your rears out of the circuit. But I don't know any good way to test that except to test the brakes and see if you can lock the rears.

[jcwxj]

First off thanks to everyone for responding. My first question is how to do a vacum bleed? The problem I am having is just like a bad booster but the booster is brand new. I have to find a solution or this jeep is going out front with a for sale sign.

[87manche]

vacuum bleeding uses a vacuum pump to suck all the air out of the system.
You can buy the kit from the parts store for about $50, or if you have a vaccum pump make one using a mason jar and some tubing.
an alternative would be speed bleeders, you can find those in the help section of the part store. They work pretty good.

[badron]

Could you define the problem a little better please? Sponge pedal or longer pedal travel then normal, longer stoping time/distance then normal or all the above. Any mods to the Cherokee that might make a difference? You replaced the pads did you go to any of them wirdo pad stuff, dustless, high ceramic etc?

[jcwxj]

To be a bit more specific the pedal travel is a little long and you pretty much have to stand on the pedal for truck to stop.

[93XJdude]

To be a bit more specific the pedal travel is a little long and you pretty much have to stand on the pedal for truck to stop.


sometimes mine does the exact same thing. 93 sport 4.0 aw4, new pads, shoes, rotors, and drums.