I have a 1998 Cherokee XJ. I have clunking from both sides in the front. I am 99.9% sure the clunking is coming from the front brake pads. The clunking goes away if I lightly apply the brakes.

I have installed the thickest abutment clips that will fit. I have installed the wire clip on the bottom of the pads/calipers. I could not find any way to install the wire clips on the top of the pads.



My theory is the pads have just enough friction to ride up as the wheels turn. Then any bump is enough to make them fall back down making the clunk.

Other than the clunk it seems to be 100% benign.

Any knowledge out there telling me I am wrong and it is something else? Telling me what to do about it?

 

Sure it's brake and not something else? Like ball joint or something else loose in the front end? Got an action camera? Stick it under pointed at the steering gear and see what's moving when it happens?

 

Thanks for the reply cfaber,

Like I said, I am 99.9% sure it is the front brakes. The ball joints, the steering knuckles, wheel bearings, hubs and most of the other front end stuff is new or has no discernible movement. This clunking predates the installation of the ball joints, the steering knuckles, wheel bearings and hubs.

I'm hoping someone else has had this problem and fixed it.

 

Do the caliper slide rails on the steering knuckles have grooves worn in them where the pad sits?

 

I installed NEW steering knuckles because the slide rails on the knuckles had groves in them. There are no grooves where the pad sits.

 

Ok
is the vehicle 2wd or 4 wd, you don't mention that.
Assuming it's 4wd:If you have one of the front wheels off and the transfer case in 2wd if you rotate the wheel clockwise then anticlockwise seems like you should get the clunk if your brake pad theory is correct.

Again,if it's 4wd, I would take a hard look at the front drive shaft and the half shafts.

 

Sorry I didn't fill out my profile before. It is a 1998 XJ Sport 4WD.

It has new front axle u-joints. The splines on the axle half shafts show no wear.

I have tried your spinning a wheel idea. Nothing happens when manually spinning anything. I don't think I can spin it fast enough or maybe there needs to be some weight on the hub causing a little rotor deflection or????

There is some backlash in the front differential. It seems about normal to me. You would think that if it were differential backlash clunk it would go away in 4WD but it doesn't.

The clunk has been there for a long time. It seems benign. Because I haven't found a way to quieten it, maybe it isn't benign!?

 

Given all the parts you've thrown at it and the fact that the clunk had caused no problems at this point I would just drive on.
in the meantime while you're waiting for something to fall off I would suggest cranking up the music with an appropriate tune. For a clunk "In-A-Gadda-Da-Vida" (the long version) by Iron Butterfly " would work .

I don't think it's the brake pads,........the fact that I think you said that you get the clunk when you go over a bump is a clue

 

Every time you tap or hit the brakes, the body shifts forward and down. I would check the shock mounts , upper and lower and I would disconnect the sway bar and bungee end links and bar out of the way for a test run...see if your clunk goes away

 

QUOTE=exasemech;3729714]Given all the parts you've thrown at it and the fact that the clunk had caused no problems at this point I would just drive on.
in the meantime while you're waiting for something to fall off I would suggest cranking up the music with an appropriate tune. For a clunk "In-A-Gadda-Da-Vida" (the long version) by Iron Butterfly " would work .

I don't think it's the brake pads,........the fact that I think you said that you get the clunk when you go over a bump is a clue[/QUOTE]

Thanks for the reply.

I didn't replace the parts because of the clunk. The Jeep has 200K miles driving and another 65K miles being towed behind a motorhome. I replaced the steering knuckles because they had deep grooves worn into them by the brake pads. I was doing a routine brake pad replacement when I discovered that. This particular clunk/click existed before I did the brake job. While I had it apart I replaced the hubs and the axle half shaft u-joints because one of the u-joints was making noise. The axle splines looked pristine. The process of changing the steering knuckles required the installation of all the ball joints.

I cannot find ANY play in any of the bushings for the control arms or the tie rod ends.

In the process of doing all this I discovered that the shocks were too long so I replaced them and installed new bushings. I have checked the bushings and there is no evidence that shock bushings are the cause of the problem. Getting the proper length shock didn't change the symptom. I need to get longer bump stops because under extreme flex of the front axle the tire may contact the plastic finder liner. No damage done, just a scuff mark on the plastic.

The symptom goes away with the slightest pressure on the brake pedal. Not enough to feel ANY slowing of the vehicle.

Thanks for the reply.

I not talking about tapping or hitting the brakes. I apply the slightest pressure on the brake pedal. Not enough to be felt as braking and the clunking/clicking/noise goes away. The noise is not always there. Sometimes no noise. There seems to be no connection to anything identifiable to when it may clunk and when it doesn't clunk.

Long Long ago I put Wilwood brakes on the front of my 340 Duster. It had similar clicking that I eliminated by devising a spring from piano wire. That stopped the noise in that case. The Jeep doesn't appear to be as easy to make spring clips for as the Duster was.

I was hoping someone had the same kind of noise and had a cure.

An old Jeep is prone to clunks. I have had plenty. Worn motor mounts, worn transmission mount, worn rear spring bushings and lots of other stuff. I have eliminated those clunks.

The front sway bar has been disconnected for months. I doubt the sway bar had anything to do with it. The rear sway bar was removed a LOONNG time ago.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I am a competent do it yourself person. I've been to lots of rodeos! I did all the bodywork on my Duster when it was >25 years old and had some rust on the quarter panels. I installed the new motor with headers. Headers installation in a Duster is not straight forward. There is barely room for headers. I fabricated a cross member for the Richmond 6 speed transmission I installed. I rebuilt the transmission hump in the car to accommodate the bigger transmission. Now 30 years after the body work and paint job it still looks pretty good.

I was going to add a picture of the Duster but the Manage Attachments routine hangs up at 90% and won't go any further!

 

Appears you have all the bases covered...There's only two ways they could make noise and you've got the most offending one covered with the abutment clips...Only thing left is the actual pad clearance before the brakes are applied..How's the pad clearance to the rotor ?? Also, there's a product called disc brake quiet.. You apply it to the back of the pads and it acts as a cushion to keep the pads from moving around/squeeling...At this point that's all you got left to try if everything else checks out..

 

Thanks Corky, I think I will give it a try. If it stays tacky it will collect a LOT of dust because of the places the Jeep get driven. It is not normally a paved road vehicle! Off-road is where it lives.

 

I'm pretty sure it's like a high temp gasket maker type stuff that dries but its flexible to a certain extent..Something that adds a cushion to the pads...I wouldn't add anything that stays wet myself...lol... google CRC brake quiet and a bunch of info will come up...PS.. I'm looking at your supplied pic and I'm not seeing any silicon brake grease on your sliders...Yes, I know it's an offroad vehicle but here's the thing..If your abutment clips are on the tight side they may be sticking a little when the brakes are applied and snapping across the slide...Just throwing it out there...
And let's see some pics of that Duster !! You might need to make the pic a touch smaller to upload it...I use 1100-1200 width for most pics... Here's my Mopar out for the first spring run....

 

Thanks Corky, I don't think excessive clearance between the pad and the caliper can the problem. On disc brakes that is sorta defined by the amount of run out the disc has. Bad bearing could cause excessive runout and warped rotors could cause runout. I have new hubs, therefore I have new bearings. There is no bearing movement when doing a bearing test. I think a warped rotor would cause a pulsing brake pedal. I don't have any pulsing.

I am pretty sure the noise is benign and is not indicative of some hidden problem. I have recently obtained a camera that I can use to record movement while driving. At some point I may try to use the camera to capture what is happening.

In the meantime, I have order the CRC product you suggested. I have very little faith that it will fix the noise but for $9 it is worth a try. I will applying it on a rainy day and do it when I have nothing else to do.

Thanks for all your suggestions.

 

Your Mopar is looking sweet! I bought my Duster NEW on April 1, 1970. The body has 310K miles on it! The engine and transmission about 55K. Engine is 360 MAGNUM from 1996 RAM. It has a custom camshaft and other tweaks. Estimated 400 HP.

I live in Colorado at 7000' elevation. HP is only about 300 here at home! (: Most a garage baby now!