Jeep Cherokee ABS Brake judder low speed ***FIXED***


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By Blaird52 - Thursday, August 31, 2006 4:39:02 AM
Hi all....just had an 1997 jeep grand cherokee.....The ABS pump was disconnected when I bought it.   It worked fine the brakess were perfect.Recconnected ABS pump but the brakes judder,also making a metal on metal grinding or scoring noise.It feels as though the brake is pushing on a ribbed drum.

Needs MOT soon.Look forward to your replies. Thanks boys.......(and girls)!!

Blaird

By cjawahir - Thursday, August 31, 2006 8:00:33 AM
hi , try to scan the ABS module  for fault codes . I had a problem like yours, the ABS pump was coming on and locking up the brakes, the ABS unit was bad.

oh and if your rotor disc has a small bend, you will feel it more with the abs on, the judder at low speed.

cj

By TONY_GINGELL - Thursday, August 31, 2006 8:43:41 AM
Hello Blaird, and welcome to the Forum.

It would be best to get the brakes checked ASAP if you are getting "grinding" noises, and as CJ has stated, get the ABS checked for fault codes at the same time. (Is the grinding only there with the ABS pump connected?)

Please note, that on some ABS systems, the system is also used to regulate pressure to the rear brakes, so possibly the brakes may not be working as well as you thought.

The above will have to be done before the MOT, as the operation of the ABS warning lamp is part of the test.

By Blaird52 - Friday, September 01, 2006 3:42:31 PM
Thanks CJ and Tony....

I will take it to the dealer...

The forum owners suggest that 99% of faults with this motor are module related..but I suppose the scan will reveal that.

There is only a problem when the ABS unit is plugged in.The brake s work fine when unplugged.

Will update you when I find anything out.

Can we get a module this side of the pond.?...you can get one on ebay from this Companys sister co in the states,but the postage is ridiculous.

Many Thanks again.

By DaveH - Friday, September 01, 2006 4:09:17 PM
Does this brake judder only happen at low speeds ? have  you checked the reluctor rings for corrosion/damage

Regards

DaveH

By jez1342 - Friday, September 01, 2006 5:28:26 PM
i've had a few of these that have had the rear sensors knocked away from the reluctor ring inside the drums. worth taking drums off for a look, expect to see one sensor further away from the ring than the other.
By Blaird52 - Saturday, September 02, 2006 4:07:18 AM
i've had a few of these that have had the rear sensors knocked away from the reluctor ring inside the drums. worth taking drums off for a look, expect to see one sensor further away from the ring than the other.

Cheers Jez....

Not much knowledge of mechanics .....but I can check that.....how much further away would they be....would it be obvious or millimetres,,??

Can the sensors be removed for testing and cleaning without any fluid loss.

What do they look like...jesus I need a manual pronto.

Thanks again to all.

By jez1342 - Saturday, September 02, 2006 4:15:55 AM
the easiest way of checking them is on a two channel scope. connect up to both sensors, start her up, put her in gear and see if the voltages between the two differ.

failing that, what i've done before is to adjust the sensors so that they are as close to the ring as possible but never touching (spin wheel to make sure). they are easy to adjust and to remove and clean (quite important that they are clean and the rings). if there is a difference in the air gaps, it's usually quite obvious. hope this helps, Jez.

By Blaird52 - Wednesday, September 06, 2006 9:02:27 AM
Thanks ....Thannks.....Thanks...

I went ot a dealer to get the codes out of hte ABS unit and hey presto they found part of the ABS ring (which the senosrs check) was missing/damaged..new half shaft reqd around £700 to repair. Shoot. !

Went to see a mate....he had a look,we took it out, and he built it up with weld and machined it back with the splines on and hey presto good as new.

Thanks again all.

By Dave Hill - Wednesday, September 06, 2006 4:53:56 PM
Blaird

What’s his name? I want to employ him Smile

Good luck with the repair
By Bloders - Wednesday, September 06, 2006 4:58:08 PM
On the subject of down to Earth repairs:

Has anyone tried welding up a dual mass flywheel?

I know of a couple of people who have done this and reckons it is the way forward.  One of the guys did it to a Fronterra (I think), whilst the other works for an HGV fitting firm.