Popping/tapping sound from front end when braking or coasting

jdbell2004 · 09-22-2009, 12:59 PM

Did some searching and came up with the track bar being the possible culprit. I just want to note a few things.

1. I recently replaced my front axle seals, they are leaking again so I don't know how much fluid is in the differential.

2. When the differential was serviced and re-shimmed, there was a tiny bit more play than is specified in the manual. I'll check my old posts and find exact numbers for you.

4. I didn't seem to notice the sound when in 4hi, but did notice a slight humming sound when braking.

3. When I used the parking brake to to slow down I do not hear the tapping sound from the front end.

Could the cause be my brakes? Or is it possible there is a problem with my gears in my differential? It was serviced nearly a year ago, about 10K miles back and just recently, within the last 3k miles, I've noticed the sound.

jdbell2004 · 09-22-2009, 01:07 PM

The backlash is a little out of spec however. It's at .0100 in. and spec is .005-.008 in. However, the ring and pinion gear are not new so I believe, and please correct me if I am wrong here, that this will not cause any issues.

I was told this may lead to a little extra noise, not really any serious issues though.

jdbell2004 · 09-22-2009, 08:13 PM

Got her jacked up and rotated the front wheels a bit, seems the differential makes a little noise when going between forward and reverse. Fluid level seems fine. A little below the fill hole. Banged on a lot of stuff down there, nothing seems to be loose...

wmeyer116 · 09-22-2009, 09:08 PM

maybe the axle u joints

gtospeeding · 09-22-2009, 09:17 PM

is the popping comming from the wheels or from the front driveshaft area?

Im getting popping from the front wheels on my 97 cherokee when Im braking and sometimes when Im going up an incline, I also get a humming from the front driverside when driving between 25-50mph

I know its not:
wheel u-joints
wheel bearings
brake pads/rotors
control arm bushings upper & lower
swaybar bushings
TRE joints (steering links)
shocks
driveshaft u-joints front and rear

the only things that I havent replaced:
track bar
springs
ball joints, but they are tight no slop when wiggling the wheel

all these parts I have replaced were bad, the jeep was very neglected when I bought it with 155k miles on it

Do stock springs go bad??

Jeep450r · 09-22-2009, 09:40 PM

Check the lower track bar mount. See if it is stretched or wallowed out

jdbell2004 · 09-22-2009, 10:38 PM

lower track bar mount is good. however the noisy (left) wheel u-joint seems to have a bit of play. the right side as a tiny bit but not as noticeable as the left. I notices part if the joint is attached to the axle, how do i replace this without replacing the axle?

jdbell2004 · 09-23-2009, 07:42 PM

Just got her all done. Very simple job relative to some other PITA things I've tried to tackle. Decided to have my rotors turned...took forever! They were very very warped and glazed. Replaced the pads too. Doing great and no more noises from the front end! Did both of the u-joints and out of the 8 caps, only 3 were not completely dry and rusted out. Defiantly needed to be done. Kinda wanna do all my u-joints...

Haleyrz · 09-23-2009, 08:52 PM

so do you think your noise was coming from the ujoints? I ask because I'm having somewhat similar problems, but i'm not exactly sure how to check for the last one.
1) When turning i've got a popping sound. It use to do it all the time when turning under slow speeds, but now it doesn't do so all the time, and is much more quiet when it does happen. It only comes from the driverside wheel. I am suspecting my lower ball joint on that one. I had a friend crank the wheel vigorously while i looked at all the bushings, mounts, ect, and I did notice the track bar moving up and down at the upper mount. It made a very faint noise when doing so, a different noise than the one above.
2) Last but not least I replaced my front rotors and pads, and about 200 miles later when braking i could hear and feel a popping as I slowed. So far it only does so when braking, fast at first and slows as you slow. I checked and my rotors and pads seem fine, so I'm thinking it could be the wheel u-joint on the driver side too.....but I'm not sure how you check for those. So to recape I need to tighten my track bar and bushings, possible lower (or both) ball joints, and replace u-joints.

thanks in advance for any help/advice!! Threadjack over.

jdbell2004 · 09-23-2009, 09:06 PM

Threadjack away! I was able to check mine by taking the wheels off. I grabbed the hub and rotated it while watching the u-joint. If there is play in the joint (ie. the hub side moves even a tiny bit before the axle moves) then you should probably replace it. Popping while turning may be wheel bearings. Jack the front wheels off the ground. Grab the top and bottom the wheel and try to rock it, same on the sides. If there is play, you may need new bearings. As far as popping while braking, it may be you caliper malfunctioning (ie. gripping and releasing causing a popping noise). I have (had) that same sound, and could kind of feel it as I applied the brakes. I just had my rotors turned and new pads. Only put a couple miles on it so far so I don't know if the sound is gone. However my pads wore unevenly so I believe the popping while braking is my calipers or my pads. Just some ideas, I'm not the best at diagnosing, I usually rely on this forum for my advice!

Haleyrz · 09-23-2009, 09:24 PM

hey i knew i was forgetting something! Yeah, checked out the wheel bearings a few times since I bought it by doing the wheel wiggle while off the ground and there are solid, no play, no noises while spinning. I suppose I need to check out the calipers more, but my old pads were worn almost to the metal, and they were perfectly even. Wont rule out the caliper....but i'm still leaning towards the u-joint i guess.