Excitable Boy

Just bought a '93 Grand Cherokee Limited for $1500 dollars. It is sweet! A little beat up on the outside, but cherry on the inside! The only major mechanical problem is with the ABS system. I'm just looking for opinions on this subject. The ABS kicks in on dry roads at 10 MPH or less. It happens every time you brake at slow speeds. Kind of dangerous if you don't take care in braking. If you apply too much pressure to the pedal when the problem is occuring, the pedal goes to the floor, and the brakes will lock up.
The previous owner said he replaced the ABS sensor, and the problem is an exciter ring that is worn out. A local "Jeep specialist" said "B.S.- it sounds like the ABS pump".
I have noticed an occasional loud "motor or pump" sound coming from behind the dashboard and behind the steering wheel. Something comes on and shuts off about once per ride in the Jeep. If I'm correct, it's coming from around the master cylinder.

If it is the ABS pump, the mechanic said I'm looking at $1000 dollars. He did say that in 20 years of fixing Jeep Grand Cherokee's, he's never seen an ABS pump go out.

Opinions much appreciated! Dean from Denver, Colorado

ct67_72

try and find someone with a scanner that can get data. watch the wheel speeds and see if any are different while maintaining speed on road. it could be an abs ring. doesnt really sound like the motor, something would have to tell it to come on. I cant really see it coming on by its self randomly. You can also look at the rings on the front axles, look for cracks or anything visable.also make sure the sensors are clean, I have seen people run brakes metal to metal, and have enough metal on the sensors to make them read incorrectly, even after replacing brakes

dabat

x2

gully369

I had a similar abs issue when I broke the tone ring changing a u-joint. I just unhooked the sensor. who needs abs, I always found it annoying anyway. ABS was designed for people who couldn't control their foot when slamming on their brakes, thus skidding. It is a mash and pray system. It allows the the driver to slam on the brakes and steer around danger.

dabat

So steering around danger is a bad thing?

Bustedback

A crappy connection at one of the sensor plugs will cause an inaccurate speed reading. The ABS system on these is a very reliable system, I'm not saying they don't
ever break, but once you get it fixed it should last a very long time without any issues.

Oh, and ABS is a good thing to have when it works correctly.

Excitable Boy

Well, thank's for the replies. While I am interested in finding out what is broken on the ABS system, and I realize that next year I will have to reverse what I've done, I simply pulled the 2 relays, and 2 fuses related to the ABS system from the power box under the hood- just north of the battery.
I was concerned with losing the speedo, because I read that this was possible, but it wasn't true in my case.
ABS perfectly disabled with absolutely no electrical side effects- except now the ABS warning light stays on.
The Jeep brakes perfectly.
To be honest, I don't care for ABS anyways. Yes, I understand that ABS keeps the vehicle straight when sliding (and I know this thread will become a 100 reply debate about disabling your ABS system), but I've been driving on ice for 25 years without losing control. (Or, should I say I've never driven too fast, and followed too close on ice to hit the car in front of me!)
When I have the money to diagnose the ABS, I will, and I'll probably fix it. For now, I'll let it ride. Come emissions time next year, if I haven't fixed the ABS, I'll just put the fuses & relays back.
Boy, I can ramble.
One final note. After reading online for 2 hours now, the consensus- by a factor of 10 to 1 is that ABS can get you killed on gravel switchbacks!

OverlandZJ

Pull the bulb in instrument cluster.. you'v gone this far.

Excitable Boy

I need to find out if Colorado requires no ABS warning light at the time of inspection. Typical government BS if they require a working ABS at the time of an EMISSIONS inspection. It's an emissions inspection- NOT A BRAKE INSPECTION!

BTW, I did find several posts by those who have put a switch in line with the power wire to the pump motor. Sounds like it works well. Supposedly, when you have the switch "off", and you start the car, the computer tries to test the pump. When it dosen't run, the ABS warning light comes on, and the system turns itself off. No more ABS. When you want it again, flip the switch to "on", then start the car, and you have ABS again. Cool mod for sure! Especially for those who want to turn off the ABS on a trail!