Wierd popping noise at rear wheels when moving

[emosfiat]

Background. My 1980 was in need of a new panhard bar due to someone hooking a chain to it to tow. Bent the hell out of it and shifted the axle housing. Still ran ok though. No noise. Put a new panhard bar on with little effort. Axle realigned itself with the new bar. Now there is a rotational popping sound coming the rear axle area. You can feel it in the wheel when you move slow. Sounds like this, pop,pop,pop,pop then no pop for a short period and then it repeats. The popping increases as speed increasesPut car up on jackstands and there is no popping sound when the wheels are rotated. Drive shaft is solid and does not make a sound. Started the car and put in gear and no popping sounds. Popping is only when there is a load on the wheels and on the ground. Thoughts were possible wheel bearings or differential. I do have a leak around the differential housing that I have to address. I need a axlewise man to help me think this through. Thanks, Emo.

[ventura ace]

Check the rubber donut, and for signs of anything else that might be rubbing against the drive shaft. Someone on the Forum recently put in rear seat belts, and the bolts were long enough to scrape the drive shaft. That's probably not the case for you, but maybe something similar. A donut that is cracking may tend to flop around and hit things moreso when under a load than when just coasting. A broken donut can be disastrous -- until you find the cause of the noise, limit your driving only to find the problem.

Alvon

[manoa matt]

I've had a similar noise for a while now. Mine is a clicking that clicks with about every rotation of the wheel, seems to come from the passenger side rear tire area. Same thing though, only when load on the wheel. I've dissasembled that side several times and looked for signs of contact on the inside of the rim from something like the brake shield hitting a rim counterweight, nothing. The differential has all its teeth and the only thing I can think is that it's the axle bearing, which both were replaced not more than two years ago. It could be a bad axle bearing, or the bearing was oil starved and got damaged.

If you realy want to hear what your car is doing, drive along a smooth road that has a concrete wall along the side. Just coast with the car out of gear so the engine noise does not interfere. The sound will bounce off the wall and you can hear it well.

[Fi8spider]

Hi emo! you said that you put the car on stands, did you place the stands under the body? If so try again but place the stands one on each end of the diff. Experiment with this as it will line your drive train up as it would on the ground.
good luck with a result.

[emosfiat]

Thanks for the advice guys. I have the jack stands under the axel now. No noise when I turn the wheel. Only when thete is a load on the wheels. The wheel bearings sounds like a logical bad guy but I need to check the diff bearings and gears to make sure the teeth are all there. May need oil. Gasket and pinion seal are leaking. What is your take on using RTV for differential sealer for the housing instead of a gasket?

[manoa matt]

You can buy a 12" x 12" sheet of gasket material at any local parts store. Lay the cover on it to trace it out but make sure you clean all the oil off the cover first, or the RTV sealant won't want to stick to the gasket. I put RTV sealant on both sides of the gasket and no leaks yet.

The Pinion seal is a bit more involved. Remove the 4 driveshaft coupling bolts at the rear universal joint. Remove the pinion nut, and pull the rear yoke off. Use a self tapping screw, and screw it into the seal then use a pry bar to pull it out. Make sure you remove any metal shavings before installing the new seal. Clean the oil off the splined shaft and apply RTV sealant on the splines and some in the yoke, reinstall the yoke. Put the nut back on and torque to spec. Clean and install RTV sealant on the mating surfaces of the coupling surfaces and reinstall the 4 bolts, torque to spec and youre done. No leaks.

The reason for the RTV on the splined shaft and the coupling mating surfaces is that oil sneeks past the splines and into the cavity between the couplings

I've tried almost everything to re-create that click to no avail. I'm switching to alloy wheels in a little bit if that does not cure it, I'll switch out the axle shaft and bearing with a spare that I have to see if its the axle bearing.

[majicwrench]

The axle bearings are not going to make a rotating click noise. I would take a dang good look at the wheels, certainly loosen and retighten the lug nuts. Does it have hubcaps?? Take off the hubcaps and see if it goes away. Wheels with cracks will make some real neat sounds as they rotate under load. I have also seen a few noisy tires, if all else looks good rotate tires and see if noise now in front.
RTV just fine instead of a gasket, don't use too much and don't get it in the bolt holes. Clean surfaces with some sort of brake clean or degreaser.
Keith

[TulsaSpider]

You know I just started to notice a kind of metallic popping noise, the noise is light, not heavy, (hard to describe such things eh?), on mine recently. It only occurs under initial acceleration. I am hoping it's a U-joint, I haven's read on this thread anyone mentioning U joints? anyone?

[So Cal Mark]

a seized u-joint will pop as it turns since it's binding. The next step in the devolution is looseness as it grinds itself to dust

[TulsaSpider]

Yea I have located one/two locally so I can replace it/them soon. It's been so long since I have had one go out. Does this sound like a typical symptom? One in front and one in back as usual I am guessing they are straightforward?

[manoa matt]

My u-joints are about 24 months old. They include zerk grease fittings, which could be the culprit for the click. If you are getting new u-joints go for the solid version. Since installing them I learned they are weaker because the hollow space in the middle of the spider for the grease, also you can only grease them immediately prior to installation and not when installed.

[pope]

Matt, I am installing u-joints that have the Zerk fittings on the ends where the bearings are. The fitting sticks out through the hole on the drive shaft. Easily accessible for the grease gun. Are you talking about another kind, or am I in for trouble.

[TulsaSpider]

That's the only kind I see as well Pope. Matt have there been problems with these?

[majicwrench]

Always an interesting debate about greasable Ujoints. Ujoints without grease fitting come with very high quality grease and excellent seals. Ujoint with grease zerks have "looser" seals so that as youi pump grease in some can escape past the seals. Adding insult to the "loose" seals, which can let in contaminants, most people use chassis grease to lube ujoints if they lube them at all. Chassis grease is not usually up to the task. Read the fine print with the ujoint and the fine print on the grease tube.
A Mark noted ujoint can certainly make noise under a load. Most of the noisy ones I see "creak" and "groan" but I am sure they could pop as well, check it out!
Ketih

[TulsaSpider]

Mine could qualify for a creak or a groan as well I suppose noises are hard to pin down sometimes. I'd rather have the sealed kind, but I am sure these will do.
Thanks Keith!