34 replies to this topic

[fasteddie042]

Ok folks,

I am at an absolute loss on this one. I have been trying to figure out why this car has been vibrating for awhile now and i have literally run out of parts to replace.

The symptoms:

• The rear of the car has kind of a shimmy type vibration that appears around 60 and 110 KmH. It smooths out but reappears after bumps.
• They exact type of vibration reappears occasionally for a short time ( couple seconds) after going over a bump.
• it has the same vibration regardless of winter or summer tires.
• The vibration has been getting progressively worse over time.

What I have tried in order:

• I have had the tires rebalanced several times on a hunter road force balancing machine and the guy at the shop basically told me that the tires and rims were balanced fine and I would be wasting my money to have the tires rebalanced again.
• Replaced all the bushings, delta links, and end links for a total of 4 bushings.
• Strut cap bushings have been replaced
• dampers have been replaced
• springs have been replaced
• had a dealership do a four wheel alignment ( after dampers and bushings were replaced)
• wheel bearings have been replaced
• brake rotors and pads have been replaced.
• parking brake pads have been replaced.

I have now run out of things to replace in the back end of the car besides the chassis and delta links (the two big aluminum pieces)

Could the rear end alignment be that messed up?

Anyone have any ideas?

[fasteddie042]

I should also add that the wheels are OEM Volvo Steels and Volans. I also keep the tire pressure at 32 lbs.

[BEJinFBK]

Sounds pretty comprensive. Just a thought:
Are you positive it isn't coming from the front?

[fasteddie042]

the vibration feels like it is coming out of the seat and not the steering wheel. When sitting in the back seat the vibration feels worse, I even had the missis drive around while I crawled through the wagon trying to find the source of the vibration. It is definitely stronger in the back of the car. But then again whatever I have tried doesnt seem to work. Anyone in Toronto want to take a crack at it?

[Mesoam]

32 lbs is pretty low for a 17'in wheel

Sounds like it might be one of the rear wheel bearings as long as they are able to get the rear aligned properly. If they can't get the rear into spec the delta links are shot.

[fasteddie042]

I just replaced the wheel bearings today which is why I am at a loss. I will try increasing the tire pressure a bit but it seems to do it regardless of pressure.

[fasteddie042]

Just tried a higher pressure, 36 PSI front and 40 PSI rear. Now the car feels firmer but the vibration is definitely still there.

[DVolvoguy850T5]

Check the diagram out below. Have you inspected part# 37 and 42 for both links?

[fasteddie042]

both are new, less than 3000 km on them. from those diagrams I have replaced:

Front

• 1,2,3,4,5,6,7,8,9,10,11,12,13,18,21 and 23.

Rear

• 15,27,30,31,32,33,34,35,36,37,38,39,40,41,42 on both sides.
• I didn't replace 26 but I probably should have.

One more note, everything is OEM except for the springs and dampers. The springs are Eibach and the dampers are Koni FSD's

[BEJinFBK]

Might be time to find a shop with some practical suspension experience,
have them put it on a dyno or in the air and start running it up.

Find an old school guy with a good eye and a strobe, someone that knows
how to use it, and you can find some crazy stuff shaking around at speed.

[fasteddie042]

My concern is that the rear end alignment is bad. I am suspicious that the dealership didn't fully align the car and I am certain that the indy shop I brought the car to after only did the front. How far out does the back end have to be to cause issues?

[blkaplan]

Have you checked the axles?

[BlackBrick]

the only time i had a vibration from the rear that wouldn't go away was bad tires.

Could BOTH your sets of tires be out of round? Possibly you used to have bad suspension parts that wore both sets of tires unevenly?
If possible, could you borrow someone elses rims/tires from an 850 and give it a test?

Or at least swap front/back and see if there's any difference.

[fasteddie042]

Have you checked the axles?

I really hope that the axles are ok. I just had the car into the dealer and they lined everything up to the ideal values. Toe and camber front and rear. the car drives beautifly now but I still have the vibrations. In short the mechanic was certain that the rear axles were good.

the only time i had a vibration from the rear that wouldn't go away was bad tires.

Could BOTH your sets of tires be out of round? Possibly you used to have bad suspension parts that wore both sets of tires unevenly?
If possible, could you borrow someone elses rims/tires from an 850 and give it a test?

Or at least swap front/back and see if there's any difference.

I tried this but the vibe was still there. I just have a hard time believing that the winter AND summer tires are bad. Mind you the summers definitely need to be replaced but at $800 a set I want to make sure that everything is perfect so I don't burn them off. The mechanic at the dealer recommended that I replace all 4 tires and give that a shot.
The mechanic also admitted that there is definitely something fishy going on. I will be surprised if I have two sets of bad tires.


Unfortunately this will have to wait a little while since the missus just rear ended a guy with the C30. She is ok other than her ego .

[andyb5]

When you got the car aligned, did the shop provide a sheet with before and after specs?

[blkaplan]

I really hope that the axles are ok. I just had the car into the dealer and they lined everything up to the ideal values. Toe and camber front and rear. the car drives beautifly now but I still have the vibrations. In short the mechanic was certain that the rear axles were good.

I seriously hope the mechanic didn't tell you the rear axles are good.

Your car is FWD it only has axles in the front.

[fasteddie042]

When you got the car aligned, did the shop provide a sheet with before and after specs?

I didnt get a sheet but he did take me to the machine and showed me what the actual numers were before and after the allignmenr.. I should have asked for one at the time.

I seriously hope the mechanic didn't tell you the rear axles are good.

Your car is FWD it only has axles in the front.

Ha! yea I know what you mean the rear delta links, his exact words were the rear weel bearing spindles may be bent. I just filtered down to "axles".

As soon as I get a new set of tires I will report back.

[blkaplan]

I didnt get a sheet but he did take me to the machine and showed me what the actual numers were before and after the allignmenr.. I should have asked for one at the time.

Ha! yea I know what you mean the rear delta links, his exact words were the rear weel bearing spindles may be bent. I just filtered down to "axles".

As soon as I get a new set of tires I will report back.

If the tires were road force balanced i doubt its the tires. That type of balancing, from what i have seen, will detect any problems including faulty and flat spotted tires.

Please keep us updated though, my 850 has a similar issue that i haven't been able to track down.

[BlackBrick]

just throwing things out there, but could something heavy be loose? Perhaps the gas tank?

[fasteddie042]

just throwing things out there, but could something heavy be loose? Perhaps the gas tank?

hmm interesting thought, I will check that tonight.

I would also like to add that with the new allignment and tire balance the car rides great except at 60is and 110 .