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Dear sredwine,
Good p.m. and may this find you well. I empathize, because until quite recently, I've been in the same boat. Gather close, O Brickboarders, and learn from the cautionary tale, set forth below.
About a year ago, my 1993 940 (then 106K miles, life-long Southern Louisiana car, now in New England) hit a 2"-3" tall paving step. A paving step is the leading edge of a layer of asphalt, which edge was not "feathered", so that there is a smooth transition up to the top of the new layer. My speed at impact was 65-70 mph.
The immediate damage: a ruptured tire sidewall (that went flat, in my driveway) and a bent tie rod.
I had tried for several weeks, to get the road-builder to fix this hazard. Their project "safety officer" - an MIA (moron-in-action) - was unable to grasp the extent of the danger, posed by a 2-3" tall step, facing oncoming traffic!
About 6 months ago, the same car hit a crater - 3' long, 2'-3' wide, and 8" deep - on the same road, still being widened, by the same firm (it has since gone bankrupt and been taken over by a larger outfit).
The combined latent damage:
- all four wheels bent out of true
- all four tires compromised
- strut rod bushings wrecked
- motor mounts wrecked
- one strut bearing popped open; the other compromised
- struts compromised
- hubs damaged
- spindles damaged
I take this car to a Volvo MasterTech, whose praises I have recounted in posts on this board. He replaced both tie rods after the first impact and the strut rod bushings after the second impact. I had the motor mounts done elsewhere, as some other work needed doing, that my MasterTech does not care to do. I replaced the wheels - new from a Volvo dealer - and the tires (Michelins).
After all this, there was a persistent "shimmy" in the steering wheel. Were you to be next to me, you'd think I had some sort of neurological problem, that created a tremor in my hand and forearm (only in one hand, and only while that hand was on the steering wheel).
At length - after tire rebalancings, re-alignments, etc. - the shimmy remained.
To reassure the road-builder's insurance company that the problems were not imaginary, I took the car to:
- another independent MasterTech
- two Volvo dealers
- a front end specialist.
The other MasterTech and one of the Dealer Techs, noticed the tremor (one did not). All said that nothing was "obviously broken", given the work my MasterTech had done.
The front-end specialist adjusted the steering rack, and pronounced all to be well, even though the shimmy remained (he was and remains wrong; I won't go back there).
My MasterTech, at my request replaced the struts and the bearings. When he pulled the left (driver's side) strut unit, strut bearings fell onto the shop floor. He replaced the struts and the bearings. That turned the shimmy into a shake.
The reason: when the strut was free to move - because of the failed bearing - the tremors originating from the damaged hubs were only party transmitted into the car's body. Once the new struts and bearings were in place, the tops of the struts were tight. The result: the tremors from the damaged hubs were transmitted directly and fully into the body. Shake replaced shimmy.
Yesterday, my Mastertech replaced both hubs. That turned the shake back into a shimmy, albeit a far smaller one, than had been present, before strut replacement. I emphasize that because this car had spent its life in southern Louisiana (near New Orleans), its front end was literally factory-new, as smooth as the day it left the factory, in Gothenburg, Sweden.
I conclude that at least one spindle has "flat spots", caused by the impact shock wave's twisting the hub, driving the bearing surfaces into the spindle's surface.
On the left hub, the shock wave was so severe, that it caused bearing grease to be extruded from the bearings, into the hub's "sleeve", in which the axle nut resides. There is not usuallly even a speck of grease in this area.
The spindles will have to be replaced.
The moral of this story: sometimes the damage to items is not obvious, even to well-trained eyes, because the damage involves distortions too small to be seen by the unaided eye.
Such distortions - perhaps a few thousandths of an inch - are large enough to create tremors and shakes, when the distortions are at the center of rotation of a large mass, rotating at 800 rpms (at 60 mph - Ώ mile/minute or 88 feet/second] - a 195R65 tire turns 807 times/minute).
The bottom line: unless you can find someone, who has seen the exact same problem, there is no alternative but to replace parts, starting from the impact point, and moving away from it. The most severe damage occurrs close to the impact point. As a shock wave spreads, its energy dissipates.
In the case of the stiff steering, I'd suspect damage to the ball joint, tie rod, and rack. I'd replace them, starting with the ball joint. I presume the spindle has been replaced.
Hope some of this helps.
Yours faithfully,
spook
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