97 850 wagon rear wobble/clunking Topic is solved

dairyqueen814 · Post by **dairyqueen814** » 14 Oct 2016, 08:59

Hi all,

I just got a front end alignment done as well as getting all four wheels balanced because I had highway wobble in the steering wheel and supremely uneven tire wear. I also had a pretty severe wobble braking from 70mph to exit ramp speed right around 60ish mph it would shake under braking.
I also had to order plastic hub rings because my wheels are slightly bigger than the hubs they need to go on.
I still have some highway wobble but I'm hoping that goes away when I get the rings.

Since the front end alignment I still have a pretty severe REAR shaking under braking coupled with a loud knock/clunk at the same frequency as the wobble. The sound seems to be coming from somewhere around the rear driver side door/cargo area. My shocks appear to be fine and when I bounce up and down on the rear bumper nothing clunks. I also can't seem to replicate the clunk without braking hard from higher speeds. Maybe some type of bushing or mount in the rear suspension? Both bump stops are good as well.

Any thoughts on where to start would be appreciated!

Post by **misha** » 14 Oct 2016, 17:36

I would say that the problem is in additional hub rings.Get rid of that plastic s*it and buy metal rings.
The other possibilities are that rear rotors,wheels or tyres are bad.

Post by **cuhfs** » 15 Oct 2016, 07:08

I have had Rotors warp due to way over tightened lug nuts by tire shop.

dairyqueen814 · Post by **dairyqueen814** » 17 Oct 2016, 08:04

Any way to check for warped rotors? Or should I just order a new set?

Post by **scot850** » 17 Oct 2016, 11:36

Remove the rear wheel and refit 3 of the lug nuts. Make sure they don't foul the hub from turning when tightened down. Then turn use a pencil mounted on anything you can from the back plate so that it touches the outer face of the braking surface and turn the hub and look to see if the pencil moves away from the hub or rubs harder.

When you get the vibration is it all the time, or when you are braking only? If it gets worse or better when braking do you feel it through the steering wheel or the seat of your pants. Steering wheel is usually front end related, seat rear end.

What wheels are you using? As you are using hub rings you may well find it is due to damage to the rings (plastic rings? Wow!). We had a member looking for a long time for issues with vibrations and eventually it came down to the wheels not seating correctly as he had fitted wheels that were not correct for his hubs. They were Volvo but fro his model. If you think it is coming from one side, if you have a spare, you could try substituting it with one of the wheels and see if it makes a difference. Try both sides.

Finally, it could be the parking brake shoes have delaminated in the rear hubs and are binding causing the vibration/wobble or the parking brake cables are binding.

Neil.

dairyqueen814 · Post by **dairyqueen814** » 08 Nov 2016, 08:55

I replaced the rear rotors and it seemed to help but even when the car doesn't shake I still get a clunk,knock that sounds like it's coming from the rear driver side. Again I checked all the shocks and mounts and I can't find anything. But it really does sound like a shock is wobbling around back there.

Post by **erikv11** » 08 Nov 2016, 09:49

dairyqueen814 wrote: ... Maybe some type of bushing or mount in the rear suspension? ...

Yes, this is exactly the place to start!

Inspect the rear trailing arm bushing on that side (both sides, why not?), you want to check if the rubber on the center shaft in sorry shape like this

Or intact like in this new one, freshly installed

There are several threads on here about this part, here is one:
https://www.matthewsvolvosite.com/forums ... =1&t=64918
And a link to a much better tool you can borrow from MVS to do the job (this job is a handful, to be fair):
https://www.matthewsvolvosite.com/volvo- ... lue-loaner

Jaguar xjs · Post by **Jaguar xjs** » 08 Nov 2016, 14:14

I also had a clunk in the rear. Looked at the fittings posted above and they were fine. After jacking the rear, I put the floor jack on the transverse arms to check them. Found both left and right mounts broken off. The transverse arms were banging around back there for quite awhile since it was obvious they have been broken for a long time.

Got lucky, no bolts were frozen but it still is a big job to change them out. Next up is a 4 wheel alignment, rotate and road force balance the tires and wheels.

Gordon

dairyqueen814 · Post by **dairyqueen814** » 09 Nov 2016, 09:57

Thanks! I'll check them in the next day or two. It seems like the most likely answer. This is kind of my final frontier for Volvo 850 work. It's the last part of the car I'm not intimately familiar with.

Jaguar xjs · Post by **Jaguar xjs** » 09 Nov 2016, 16:43

DQ, the rear end on this car still has me stumped! I've been wrenching for 40 years and still can't figure out the best way to use a floor jack and place jack stands in a safe spot to do the work I want to do. Hope you find some answers!

Gordon