740 random wheel shake

cornholio42 · Post by **cornholio42** » 01 Mar 2012, 21:19

1990 740 16v, 192k

I have driven the car for days without issue then rather randomly it will start shaking, violently at times. It feels like the front passenger wheel (sometimes feels like both) are coming off the car like 4 lugs fell off and the 5th is backing out. When I stop I expect to see the tire sitting crooked or a shredded tire, but everything looks fine.

With how aggressive the wheel shaking is I figured the problem to be obvious, but didn't find anything like so. The outer tie rod ends were wearing down, but not serious, I replaced them. Ball joints were worn out and needed to be replaced, I did so. The right sway bar link was a bent up mess, left wasn't bad, I replaced them too. Everything else looks okay to me.

I test drove it tonight, got about 12 miles down interstate, pulled off and the shaking started again. The steering wheel kicks back and forth like its having a seizure. I can tap the breaks and reduce the shaking. Cornering calms it until I straighten out. If I come to a stop then move on the shaking sometimes goes away.

So now I am thinking strut mount bearings? Or wheel bearings? I assume wheel bearings going out would be a more consistent problem. Strut mounts I haven't a clue. A fellow Volvo enthusiast said my alignment is off, but I haven't looked into that yet. The problem feels too mechanical like something is worn out or coming apart.

Thoughts?

Post by **MoVolvos** » 02 Mar 2012, 02:29

Check the bushings and attachment points of the steering rack. Enlarge the picture in the link.
http://www.partsgeek.com/catalog/1990/v ... _rack.html

Blessings,

BKM

D_V_ENT850R · Post by **D_V_ENT850R** » 02 Mar 2012, 14:24

Rotate the tires maybe a shifted belt in the tire. I had one do that to me was fine one day then when I hit 65 the next day it was one hell of a shake. Check it out.

Post by **MoVolvos** » 03 Mar 2012, 01:09

D_V_ENT850R wrote:Rotate the tires maybe a shifted belt in the tire. I had one do that to me was fine one day then when I hit 65 the next day it was one hell of a shake. Check it out.

Back in the mid 90's we call it a Blister or Bulge. Tire industry using "Shifted Belt" to be PC. When a belt is shifted it is damaged. Putting it on the back wheel if it is not bad can cover the symptoms. You can rotate out, most of time Radial pulls but not shifted belts the tire is damaged.

Thread: Bad front end shake, I need help diagnosing it UPDATE! Shifted belt!
http://www.w-body.com/showthread.php/41 ... ifted-belt!

Blessings,

BKM

adki110 · Post by **adki110** » 03 Mar 2012, 02:37

Have you checked the front strut rod bushings?
http://www.ipdusa.com/products/5306/103 ... g-mini-kit