Signs of rear hub bearing failure?

Generalee0527

1st Gear Poster
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Jan 4, 2024
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Location
SW GA
Vehicle Details
97 Tbird, pbr front brakes, Sport edition 4.6 w/ 346k total miles by me the one and only owner.
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Have heard a loud thump and sharp ting at various speeds, generally at low speed while accelerati g or maneuvering in parking lot. Just clocked 359k miles today. Wondering if it is hub, u-joint, half shaft?
 
A bad wheel bearing usually manifests as a growl as you pick up speeds, most audible in the 30-50 MPH range IMO. A bad U-joint could contribute to driveline vibration and cause clunks when the direction of power through the drivetrain reverses (e.g. accelerating or engine braking).

If you hold your foot on the brake and switch between reverse and drive, a thump would imply driveline play. If that's the case you'd need to isolate the location of the worst of it - though I'd go out on a limb and say there's undoubtedly some play in all the major components by now.

You can do some basic tests to determine how much driveline wear you have, and localize it.

Put the rear end of the car in the air so both wheels are suspended. With the transmission still in park, try and turn one of the wheels. If you have a limited-slip differential the tire should stop after minimal rotation. With an open diff (or a limited slip that has worn out clutches) the tire on the other side will spin in the opposite direction. You might need to brace the other tire or find a helper to hold it still (or just to watch other components for movement).

To narrow down the play in the driveline, you would need to watch the halfshafts and driveshaft carefully relative to the motion of the tire to determine which moves (and how much) when you rotate the tire. If the tire moves without the halfshaft moving, it would be a worn out CV joint in the halfshaft at the wheel bearing. If the halfshaft moves but the driveshaft doesn't, pay close attention to the inner segment of the halfshaft at the diff to determine if that end is worn, or if it is worn gears in the diff. Give the same attention to the driveshaft after all the play/slack in the halfshafts/diff have been taken up and the torque of your spinning the wheels is transferred to the driveshaft. If the pinion end of the driveshaft moves but the driveshaft itself does not, it could be the rear U-joint. If the driveshaft moves but the driveshaft yoke does not move, it could be the front U-joint. You could also check the driveshaft by just grabbing it and trying to rotate it, but you'll get more torque to it by turning the wheels.

Put another way, where something that moves meets something that doesn't, there's driveline slack there. Some is to be expected... but a very limited amount, and not in the diff or bearings like U-joints.
 
For about a month now I have been hearing a chirp when slightly turning to the right at 5-10mph as I leave work thru some chicanes. This loud ting and thump like I hit a pothole but the front wheel missed it? I did notice cruising home at 70 mph that if it was under light load (not coasting) I could hear a low growl. I am suspect of the left rear hub. I crawled and looked all around and all boots are intact, no leaks on diff, driveshaft was in place and no clunk shifting between r & d. I just put new u-joints in w/ alum ds and changed fluid in different about 6 months ago. I removed the diff thinking it was bad and just had some roughness but syn oil quieted it down. I am gonna have to check that left rear hub and soon.
 
A number of years ago I pulled the hubs off and brought them, along with new bearings, to a local driveline shop. They installed them for $20 a side. Worth looking into if you don't have a 20T press handy. :)
 
Have heard a loud thump and sharp ting at various speeds, generally at low speed while accelerati g or maneuvering in parking lot. Just clocked 359k miles today. Wondering if it is hub, u-joint, half shaft?
When my rear wheel bearings began to fail at around 100,000 miles I first noticed it when I jacked up the car to rotate tires. With a rear wheel jacked up I could definitely grab the tire/wheel with both hands and make it move around.. and it shouldn't move at all.

Recently at 107,000 miles I hear a clunk at times when shift into gear and feel some slop in the drive train when on the highway and let off on the gas with no load on the car. I jacked it up, the u-joints, half shafts, and bushings are fine but there is some excessive lash in the differential, which I could see with the parking brakes applied, transmission in neutral, and rotating the drive shaft by hand. People who know more than me say that this is not to be unexpected with a car with over 100,000 miles. My bird only comes out in nice weather so at the moment I'll just put up with it until I stumble across a good and not overly expensive solution to the issue. Given the age of our cars you might also want to check the bolts/bushings that hold the rear subframe in place along with the brackets mounted in front of the rear subframe that tend to rust out over time.
 
100k miles is not very long for a rear wheel bearing; Our driveshafts suck, they are two sheets of thin steel, glued together with rtv.
They separate, and cause noise and vibration. On Lazarus, I spun them apart; if I hit second hard, it would turn inside itself, and seemed like the trans slipping. Find a 93 mark 8 driveshaft for the long haul. I bought PST aluminum driveshafts ($450) and never had another prob.In the red car and Lazarus, the og ds failed. I replaced the one in the tbird within a month of me buying it.
 
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