98 V79 NA front end vibration (control arms replaced) Topic is solved

[98v70dad]

I'd read good things about Conti's + Volvos. Odd local DT won't carry them. Could have bought and shipped & M/B'd but that also adds up. Given my experience with BFG, no more of these. Rubber rot is a fact-o-life in the South. Tires need sunscreen.

NOBODY in Atlanta ever has a decent tire for our cars that will last. A V rated tire for a normally aspirated (my model) dog of a car is just crazy. H's could make sense due to the extra ply but they are usually made from softer rubber so they can provide sporty performance. Consequently they dont last very long. I read good things about Generals (owned by Coni) but every installer I talked with said they have trouble getting them to balance.

I went rogue and put T rated contis on mine. I'm not concerned about it from a safety standpoint. I've never had my car above 90 mph and never will. The car takes me and me only to and from work so I'm not concerned about them being overloaded AND I'm not doing any fancy maneuvering that would necessitate a stiffer sidewall. H rated and V rated tires have an extra ply which is good but nobody ever carries a highly rated H or V rated tire that fits my car- they are always some second tier off brand. I went with the T's because they are excellent tires, they are reasonably priced and they have a 90,000 mile tread life. They are 95 % of the performance of the michelin primacys they replaced at about $40 less per tire. Anyhow, I got some abuse in another thread for doing it but they will be fine. The tires are just like the Michelin's...like riding on glass...perfect..

[98v70dad]

I'd read good things about Conti's + Volvos. Odd local DT won't carry them. Could have bought and shipped & M/B'd but that also adds up. Given my experience with BFG, no more of these. Rubber rot is a fact-o-life in the South. Tires need sunscreen.

Re: U-joint. Good eye. Haven't bothered to check mine as it's out-of-sight-out-of-mind.

Re: Rack mounting. "loose" meaning internally, not externally. Where R&P meet is one point. So would be the outer sleeves (metal? Plastic?) where it's guided in-n-out. Then the seals. If I had a rack in hand, I could inspect and figure it out.

Passive steering rear end delta links: This would explain unexplained RE vibration. Particularly when aggravated by rear tires that are not smooth round. These tires transmit vibration to the axles/ bearings/hubs, then to the delta arms where over time they enlarge the rubber pieces.

Do this long enough, over enough rough roads, in hot, humid weather, where black asphalt reaches 160°F , which is constantly radiating heat upwards while I'm stuck in damn Cen. Tx. traffic, in an area with only two seasons: Summer and Feb. and it all adds up.

I remember as a kid what would happen when the rubber bushings would rot in my skateboard trucks. I'd get the wobbles going fast and wipe out! Thus regular replacement was necessary to remain stable at speed and keep my skin off the pavement!

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I replaced the control arms this morning. Problem solved. No more jiggling down the road. My ride is now as smooth as glass. I'm a little surprised by it. The parts I took off don't seem bad at all except the rubber boots around the ball joints are shot.

[misha]

Something had play in it.....bushings or ball joints.

[sleddriver]

I replaced the control arms this morning. Problem solved. No more jiggling down the road. My ride is now as smooth as glass. I'm a little surprised by it. The parts I took off don't seem bad at all except the rubber boots around the ball joints are shot.

A big thumbs up!!
Great to hear your efforts paid off!

[abscate]

Two Viking horns for sled-driver!

And to kcodyjr for calling out the control arms !



Take home message...control arms can't be visually inspected beforectheygive trouble. The good ones probably last about 100k before they're suspect. Most of us on P80s should be on our third set of control arms, or our tenth junky brand one

[98v70dad]

Thanks everyone for the comments. I put in the last post from me because the parts didn't seem bad even when I could look at them closely.

I did have one issue installing them that I can't figure out. One side went in as easy as can be. On the other side when I took the weight off the suspension with a scissors jack I couldn't get the control arm up as high as I wanted it (essentially level). I got to within about an inch or so vertically of where I wanted it and noticed that I had lifted the car off the jack stand. I let the car back down until it was resting on the jack stand and went ahead and torqued down the fasteners.

My driveway is sloped in several directions so the perceived height of the control arm it may have been an optical illusion...don't know. I also installed them raised as high as they would go without lifting the car so I think I'm OK. I'm contemplating re-torquing that side but I've got other stuff to do - I don't really want to pull all of my tools back out.

I got the parts on sale for 90 each... a bargain. I ordered on a Saturday night and they arrived Monday. Free UPS ground shipping I couldn't believe it.