kcenderjim

is there a way to test or check the ABS system on a 90 cherokee? My brake light and check brake lights keep coming on. i also had an issue today where the brakes locked up on me and i was always told that ABS will not lock up.

itsanxjthing

well you would only have rear abs, but does your peddle pulse, like when you hammer on the brakes do you get a pulsing sensation

kcenderjim

no i really do not get a pulsing in the pedal. the other issue i am having though is ever since i had it inspected, every once in awhile when i hit the brakes it pulls real hard to the left. nothing like doing 70 on the highway and being pulled into the other lane. i was told it was the caliper but it doesn't do it all the time and that is what is pondering me and thinking it may be the ABS.

zman32006

I have a '90 as well and Im getting mine checked tomorrow for my ABS problem. sometimes I have power brakes and sometimes I dont =/

kcenderjim

what is yours doing????

zman32006

From what I've read the vacuum pump isnt working properly or something I have no idea but the physical issues are that the brake pedal will sometimes get extremely hard to press like I dont have power brakes and other times it'll work fine. My pump is constantly running so I have no idea what that is about. They lock up whenever I slam on the brakes really hard. thats if I can manage to get the pedal down. I have a couple of links on the brake system the 90 Cherokees have. Its called the Bendix 9 system. here are some write ups on this forum and other forums about how to change them over to normal brakes. also there is a recall on the brake system that Chrysler put out a good many years ago. but its too late for us to cash in on it now.

https://www.cherokeeforum.com/f51/xj...-upgrade-3352/

https://www.cherokeeforum.com/f2/ben...-system-14960/

http://www.naxja.org/forum/showthread.php?t=924285

4wheeldrivenewbie

i replaced my rear to front brake line which went to a junction box there was a blk round thing on the junction which i belive was rubber i pressed it and pushed it once or 2 times after that only other thing i did was pump them a couple of times and i removed a dome light fuse n put it back in then i noticed my light went out it was red said brake my pedal is there but its not stiff it will go down everytime

zman32006

The 1990 jeeps dont have the black round thing. Thats the booster. Ours have the Vacuum booster and it basically sucks bad haha. Thats why they did a recall. There is an 89 cherokee at my neighbors house that I occasionally look for parts in but it has the round black booster

black90XJ

As stated above, the ABS in the 1990 model is a 4 wheel ABS called the bendix 9. It is notorious for having constant problems and awful reliability. The system operates using a hydraulic pump on the pax side fender. This supplies pressure to a pressure accumulator (black ball looking thing) that is located next to the master cylinder. The problem theat typically occurs is this:

The pressure accumulator has a check valve so that it will hold pressure with the pump off. These check valves fail frequeintly, causing the pump to have to either run constantly or to run very frequently with the brakes applied. The pump duty cycle is exceeded and the pump fails. resulting in the loss of your power assist braking. The best thing to do is to yank the Bendix 9 master cylinder assy (its a beast) and install a dual diaphragm booster/mastercylinder/proportioning valve from a 1996 XJ. In my experience, the 1996 XJ has the closes matchup for booster rod lenght to your 1990 model. There are writups on how to do it. Here is one:

ABS exorcism

zman32006

Hey thanks I had no idea why it was going bad just I knew it was going bad.

kcenderjim

The other issue that happens when it locks up is that a clicking sound starts coming from underneath the dash. If i slam on the brakes it all goes back to normal.

zman32006

I have that too. When I barely push on the brake pedal its a rapid clicking sound. I have no idea what it is. And when I pull out of my driveway (which is a hill) I have to almost stand up to get it to stop at the bottom. Then I push the pedal all the way to the floor and like magic I have power brakes again...