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rear noise diagnosis

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jvandyke

jvandyke

Luke Skywalker
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I have this strange rubbing/creaking type sound seems like left rear, only hear it at low speed, possibly only under power. Wheel bearing? (i replaced both a few thousand miles back) U joint?
Car is for sale (unfortunately) Currently on ebay.I don't want to pass on any issues if I don't have to (I'd rather fix it than sell it with a known issue if I can).

I held the camera pointed at the left rear wheel and moved forward, coasted, back coasted. Since watching it it seems like it might be only occurring when accelerating, drive shaft u joint?

on the video it sounds like more of a popping but in real life I'd call it a creak

movie here
 
GeeBee1 said:
Bump,

Sounds like baseball cards in the spokes :devilgrin:
Click to expand...

That's where that Hank Aaron rookie card went.....

maybe those bearings from VB were crap, or I put it in backward...easy enough to pull and check I suppose. I still have the ones I took out which were probably fine anyway. Wheel feels solid though.
 
Check rear spring bushings and tighten the axle to the spring. The rubber pads b/w the axle/spring plates compress, loosen and strat to creak. my does it. I kinda like it.
 
I'm getting feedback elsewhere that is putting the suspicion on Ujoints, I'll look into that while I'm down there tightening up stuff.
 
Tightened spinners, no difference, rolled car up and down the driveway with my head by the rear wheels, there's a rhythmic creaking that seems centered and a popping sound from <span style="text-decoration: underline">both</span> wheels. Maybe something is going south in the differential? I topped off the pumpkin, it was fine. hmmmm I guess I'll just monitor it until something fails? I didn't go around and tighten all the bits yet though, will try that next.
 
Since some of the noise is centralized and both wheels produce the "popping" and tightening the spinner did nothing, I assumed the wheels/hubs are fine. When I put on the e-brake and twisted the drive shaft there was some slop, the rear flange moved with the shaft/u-joint. I'd think it shouldn't. Maybe the differential is failing?
 
jvandyke said:
I'm getting feedback elsewhere that is putting the suspicion on Ujoints, I'll look into that while I'm down there tightening up stuff.
Click to expand...

If it were the drive-line, I would think you would feel a vibration. Doesn't sound like U-joints IMHO, but maybe the diff bearing or yoke bearing.
 
lbc_newbie said:
If it were the drive-line, I would think you would feel a vibration. Doesn't sound like U-joints IMHO, but maybe the diff bearing or yoke bearing.
Click to expand...

That explanation makes the most sense so far

26/27/28 from this diagram?

Moss diagram
 
Drop the driveshaft, "work" the u-joint by hand.
If it's rough, binding or grabbing, has any rotational play, that's the problem.
If no issues, that ain't it for the noise generated whilst turning the wheels by hand.

However:

You made a statement:

"When I put on the e-brake and twisted the drive shaft there was some slop, the rear flange moved with the shaft/u-joint. I'd think it shouldn't."

Rotational or up/down/sideways?

Some rotational is normal. How much, approximately, in degrees?
You have backlash in the ring and pinion, and play in the spyders.

Up/down/sideways is pinion bearings.

Dave
 
I'm thinking loose spokes if you have wire wheels.

Take the weight off the wheels and tap each spoke with a wrench. All should 'ring' with the same or close tone. Clunk is loose spoke.

The wheel centers hang on the spokes in tension, not in compression.

Something else to check.
 
TOC said:
You made a statement:

"When I put on the e-brake and twisted the drive shaft there was some slop, the rear flange moved with the shaft/u-joint. I'd think it shouldn't."

Rotational or up/down/sideways?

Some rotational is normal. How much, approximately, in degrees?
You have backlash in the ring and pinion, and play in the spyders.

Up/down/sideways is pinion bearings.

Dave
Click to expand...

rotational movement, simulating drive situation, about 10 degrees worth (rough guess). I didn't try any up/down/sideways.

I hope to head out to garage soon, check for anything loose, and man handle the driveshaft some more, also check spokes, but like I said the noise sure sounds "centered" and both wheels "pop" so my money is on pinion bearing failing, but I'm almost always wrong with the first 2 or 3 diagnosis, which is why I ask and check over and over, I HATE buying parts I don't need.
 
10 degrees is about right for a broke-in (pronounced "broken") diff...joke, son, just a joke.

10 is okay.
If you have the tail airborne, and can rotate the shaft by hand, feel no catching or grinding, remove the shaft and rotate the u-joint through it's paces, you're okay, and look at spokes.

However, if, whilst airborne, the wheels still make the noise, most likely not spokes.
 
Poked around a bit more.
There is a pronounced oil spray pattern across the underside of the chassis right above the flange to diff. joint, the metal "cap" is pretty loose there, I think maybe this oil seal is failing? But I get no oil drips and diff had plenty of oil in it. I can't move the shaft side to side and there isn't much slop in my opinion when I "twist" the drive shaft (see video in linked pic gallery).
I tapped on some spokes but didn't hear much difference in sound from them.
hmmmm
pictures of oil spray and a little quicktime movie
oilspray.jpg
 
Pinion seals, especially brit ones, tend to ooze a bit....kinda like OLD US cars with leather seals.

I have never considered a little oil to be a real problem, especially if the pumpkin stays full.
A very small amount of oil can spred a LONG way, so what may look horrible, often isn't.

You can sleeve the pinion flange, replace seals, they sometimes still leak.
Sometimes it comes from the pinion splines, past the mating grooves in the flange assembly, past the washer and nut, and out the end by the u-joint.

When I work on a diff, I clean the inside of the flange, washer and such with Brakleen, and lay a big bead of black silicone under the washer before I put it on and tighten the nut.
Stops that source of leakage.

Dave
 
I agree with Dad, put in the air and spin it and see what you hear. That might be grease up there you see.

How many times does the wheel "pop" per wheel revolution?
 
I can't rotate the driveshaft by hand with the car up in the air but I suppose, if it is solidly on jack stands, I can run the engine and let it spin while I watch and listen from underneath. Several pops per revolution.
 
If you jack up by the pumpkin, block the axles or hub carriers with jack stands (and leave the jack in place as a "safety"), neutral, e-brake off, you'd sure BETTER be able to rotate the driveline by hand or something is seriously wrong.
 
TOC said:
If you jack up by the pumpkin, block the axles or hub carriers with jack stands (and leave the jack in place as a "safety"), neutral, e-brake off, you'd sure BETTER be able to rotate the driveline by hand or something is seriously wrong.
Click to expand...

Are you saying I should be able, with just my hand, turn the driveshaft thus turning the differential, thus turning the drive wheel. Gear shift in neutral of course. ? I could not last night but I think it was in a gear at the time. The day before though when I was feeling for play in the driveshaft I'm pretty sure it was in neutral, however the ebrake was on. I will try to turn it again, no brake no gear and see how hard it is to turn. I may also try to start the engine and let it spin in 1st while up in the air and listen for noise then. I think if it makes the noise with suspension unloaded that would be telling and I should be able to hear precisely where it is coming from too, if I can avoid hurting myself with spinning parts close at hand. Isn't that how Mark Fidrych died?
Not sure if this the accident or not but someone recently got clothing caught in the spinning drive train while underneath. Be careful out there.
 
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