The thumping starts at as low as 5mph and never stops. There is also vibration that I can feel through the foot well. Tire shop says the tires are cupping. All suspension components were original. So I figured at 150k they need replacement. Last weekend I went ahead and changed all 4 struts out with KYBs. Of the 4, front passenger side was completely seized, others were sill working. It still has thumping sound and also the vibration although a bit less than before.

So should I change other components - UCAs, LCAs, ball joints? I am assuming tires need to be replaced, but I don't want to replace those only to find out those are shot in a few months because I didn't changed other worn out parts. Any thoughts?

 

I say replace the tires and see if those other issues go away before throwing part on it unless you can tell they are worn...

 

I'd say replace tires first also. Just so you know for sure the tires and the struts were the problem.

On this car, the suspension components are very sensitive and one little broken component (in my case, the struts also) can cause tires to either chop or cup.

You can tell if the other parts are worn or not. If you can't and want to be 100% sure, drop it off at your local dealer and pay $100 for them to check the suspension components to make sure everything's in good shape.

 

a really smart friend of mine suggested once,
to see if tyres are making noise or not, drive the car on grass,
if it still makes noise its not the tyres, if its gone, your tyres are stuffed.
Easy cheap and FREE way to find out if its tyyres or not.

 

So as of now tires are changed, front UCAs and lower ball joints are replaced and the noise is still there. Now I am able to isolate the noise coming more from rear driver side. So I jacked up the rear end to check bearing. Did not notice any movement 6/12 or 3/9 o'clock. But there was definitely a difference in free spin on driver vs passenger side. Lot more restrictive on driver side. I have new hub and bearing assembly on order. The LS wheel hub assembly post was a big help. A few differences are

• GS hub is secured by four 10mm HEX KEY bolts unlike hex bolts on LS.
• The dust cover has a lip which makes it lot easier to push out of the way.
• Axle nut is indent style locking(not cotter pin), would need to replace. It is however 32mm, 12 point like LS.
  
  

 

I have the same problem in my rear tires, still unable to find the problem. They cup and feather the insides.

One member suggest lower front control arm bushings.

 

You do not need to replace the axle nut, unbent it remove and then screw it back on and put a dent in it. I had 2 of my hubs replaced and we reused the Axle nuts.

 

Took out the hub and bearing and it was definitely done. Putting everything back in was pretty smooth. One thing I would say is get the long 10 mm hex socket. That made things lot easier than the short one I was using. Lower bolt towards the rear is the hardest one to get out and put back in. Putting in the dust cap is little tricky but not that bad as long as you align the hole for speed sensor. Tightening the axle bolt pulls the cap in almost 90% of the way. It needed a bit more nudge so I tapped it with a side of a trowel and that allowed the sensor to go in. Installed calipers and tire and took it for a drive last night. The thumping is all gone . Next I need to bring in to get the alignment done.

A little extra info - GS is wife's daily driver. The car has always been serviced at the dealer. So when she first noticed the thumping (which was too late IMHO) I asked her to have the dealer check it out. Dealer said talk to the tire guy. I am a bit surprised that they didn't think it could be the bearings. Tire guys (Americas) they told us the tires are cupped but something else is wrong with suspension. To recap - changed struts (all 4), front UCAs (both), front lower ball joints(both), all tires and one rear hub and bearing. I end up putting in new axle nuts. I am thinking if one bearing went bad the other couldn't be that far behind. So I may go ahead and change that over next month or so.

 

Having drag could most likely come from brake pad rubbing and not the wheel bearings. I dont see bad wheels bearing being able to destroy a tire unless they were severally chewed up.