I just recently had front struts put on my 1998 S70GLT. They balanced all four tires, aligned the car, but it appears they did not replace the spring seats, but did replace the upper strut turn table mounts. Now my front end is vibrating like hell on the highway. Could those old spring seats cause that?

 

Usually not.
Maybe one of the tires is out of round?

 

I got them to replace the spring seats w/no labor charge at the advise of my regular Volvo mechanic. It is an improvement, but they re-balanced all tires, indexed them (whatever that means) and verified all tires and am still getting a vibration starting at around 70mph. I know that's a little fast, but that car is supposed to handle that. Any other ideas I might try?

 

Swap the tires from the rear to the front and see if it makes a difference.

 

Hmm..when I first got the tires, there was a vibration. They rotated them, and it rode like a dream after that. After the expiration of the normal rotating period, they vibrated again. So I had them rotated, and it vibrated. Maybe the two that are on the front right now are defective...

 

Could very well be.

 

OK, so now I'm on a different set of all 4 (Goodyear Assurance) and it is doing the same thing. One of my wheels is wobbly and that was placed on the back. I'm starting to suspect it could be the struts since all this started once I let them dupe me into putting those P.O.S. in. Any sugggestions?

 

What brand and type of struts were installed? At what speed does it start, does it ever even out? Do you feel in steering wheel? Rims are all round I assume, because I had one that was out of round on my pass front, it was hellacious.

 

Monroe SensaTrac. There is one wheel that is a little wobbly and they put that one on the back. They were installed by Kauffman Tire and they road-force balanced all 4 wheels. Starts at about 60-ish, and doesn't even out. The steering wheel vibrates like hell.

 

oh ok, thats the same type struts I put on mine. I haven't had any problems with my struts for about 10k though. Starting at 60, man that sure sounds like a rim weight, balance problem. Do you get any pulling in either direction at speed, or slowing down. Any unusual tire wearing? Are your CV joints ok, check the boots. How many miles you pushing?

 

I don't notice any pulling in any direction, and I did get some slight tire chop once they were rotated. The car has 72,000 miles on it, and I had the driver's side CV joint replaced this past winter. I'm not sure if the pass. side CV joint was ever replaced.

 

Turns out it is not the struts. My mechanic verified all the suspension components and has determind it's either the CV joint on the passenger side or a motor/transmission mount. Does anyone know if this is a common issue?

 

The inner joint might be bad just had to replace one on the wifes cars for the same reason.

 

When you say 'inner' joint you do mean the passenger side?

 

No both axles have an inner and outer joint. The outer is a bunch of ball bearings in sleeve looking things.
The inners are what they call a tripod joint. It has 3 wheels with bearings inside the wheels. Then the 3 wheels slide into the part that goes into the transmission. The cup looking part that the 3 wheels go into gets worn and when you accelerate it wobbles in the cup part.

 

My SV70 front end vibrates at speeds over 20 mph. The car has 88,000 and was sitting for 10 years. The steering wheel vibrates at speeds higher than 20 mph.

 

start by rotating the tires front to rear to see if anything changes. does the vibration change with braking or turning? are the axle shaft boots in good shape? given the car sat for 10 years, its quite possible the tires are the cause.

 

Tires are probably flat spotted/out of round after sitting for a decade!

 

I would think so as well. You're dealing with a tire that's not round, and that does cause shaking at unusually low speeds like 20 mpg.. It's not that unusual.

 

Some balancing machines have "Road Force Technology" There are 3 arms with wheels on them. One for each side which will measure for a bent rim, and one for the tread face which will measure for tire anomalies, i.e high/low spots, broken belts that will cause vibration even though the tire balances out ok. After a bent rim is ruled out with the left and right arms, then the wheel/tire assembly is spun the tread face wheel to measure for high/low spots, broken belts that would cause vibration. If the anomaly is not too severe, the machine will prompt the user to mark a spot on the rim and the tire. The tire will then have to be dismounted and "indexed" to match up the marks. This should smooth out any vibration due to tire anomalies.
This is all good in theory but I`ve tried it a couple times with no results. I`ll just print out the results of the test and make recommendations based on the info. It`s a very nice computerized machine with a big monitor screen and a printer, but with a bunch of apathetic techs humping tires out on it all day, I wonder about it`s accuracy these days.
Sounds like you`ve run into a real hassle, but if this problem started with the strut replacement, than maybe something got overlooked, or it really coincidently is a bad axle. Brand new axles are a lot less expensive than you`d think these days. Aftermarket, that is.