Squeaking/chirping wheels fixed by quick brake push... why?

[4WDMan]

Hi,

I've been going pretty well with my recent purchase of a 1996 XJ Limited Cherokee, with one exception - the squeal/chirp of the wheels.

The front discs have been machined twice by the Dealer's mechanic in an attempt to fix the problem, however it still exists. The first machining was done off the car, the second on the car, so it was true to itself. However, the squealy chirp remains at speeds right up to 80km/h.

I have found that I can stop it by quickly pressing the brake pedal and letting go (tapping). However, it can take a few times for the squeal to stop. Then there is every chance after you use the brake fully again, it will get back into this "mode". This lead me to believe the "piston"? braking mechanism is not retracting correctly, and hence rubbing along the disc and causing the squealy chirp.

I told this to the mechanic after the first machining failed, but he didn't seem to buy it, saying that if the second maching didn't work, it has to be the brake pads.

Somehow, that doesn't make sense, as I can't get over the fact of how it can so easily be remedied by tapping the brake pedal.

What do you guys think? Is this a common problem? Do you think it is the piston not retracting right? Would this be expensive to repair?


I need to call my dealer again to say it still isn't working, but if I am armed with a bit more knowledge of what the problem may be, they might use a mechanic that can get the job done successfully.


Thanks for your help.

4WDMan.

[Bogged]

what pads have you got? Some pads don't like having machined discs to play on! They squeal and graunch and shudder! Try and get them to use another disc? possibly one that hasn't been machined.

I had a similar problem with mine after getting the discs machined. I got new pads (bendix 4wd) and had to take it back to them to swap over with metal king pads (bendix) This has remedied the porb. Found out later that the 4wd pads don't like machined discs!

Hope this helps!

Oh.. And welcome to the board!!

[TJB]

Hi 4WDMan,
I've had the same symptoms on my heap, plus on occasion I felt a very slight 'grabbing' of the brakes. A quick tap of the brakes and all was ok again. Anywho, to cut a long story short, my pistons were shagged. Can be a bit of a problem if you play in the mud and water a lot and get junk in behind the seals.

Definitely worth a good look... if it goes on for long enough your brakes may eventually seize.
Pistons can be replaced for about $60-$70 (parts only) if I remember correctly.

[Bogged]

My jeeps only 2 yrs old.. so I hope it's not the pistons!!!

[wrench]

Check the fit of the disc pads in the guides. If the pads dont sit firmly down onto the cast guides on the steering knuckle they can move & squeak. Pressing the pedals moves the pad to a differnt position & the noise disappears temporarily.
HTH
David

[Kramer]

Hi,

had a similar prob with my 96. Can't remember what I did to fix it, I just took each caliper apart, cleaned and put it all back, and the prob is gone. Like Wrench said, everything needs to be seated and "home" in the right place.

Hey Wrench, I was tentatively trying to find ur shop the other day whilst getting a burger in William St (we're building in Samsonvale). Do you have a workshop there or are you set up elsewhere?

Kramer

[wrench]

Hi Kramer.
Our shop is in Hay Road. On the left as you head out of town towards Petrie.
Easlea Automotive Services & The Tyre Shed. Nothing flash, big tin shed with a couple of hoists, aligner, scope etc & usually cars everywhere. Certainly be glad to see you if you drop in sometime. Where in Samsonvale are you building? I suppose the rains slowing things down a bit.
Regards
David