I obsessively have 6 volvos, all pre-1984 200's, 3 of which are on the road. Three of these cars share a suspension fault; when driving around a corner and hitting frost heaves the rear of the car hops nastily. One of the three has new rear shocks, and my mechanic suggested that perhaps the shocks were dampped incorrectly for a volvo, so i bought some boge turbo gas rear shocks from ipd and put 'em on another car, and it still hops too! Could it be front shocks? Bushings? Am I just unlucky that ALL my 84's have this problem, or do others with 84 volvos see the same thing? Thanks for help!

Could be one or more of the u-joints in the driveline have jammed up. This happened to me recently. My rear suspension had been loose and getting worse...the classic volvo clunking upon take-off. Well, six months went by and I still hadn't replaced the control arms (aka 'dog bones' or torque rods) and I went over a speed bump at about 10 mph and it jerked the driveline so hard that one of my u-joints locked up. The rear end started making a terrible scraping noise even at very low speeds.

I replaced the torque rods, and the u-joints and I'm back in business. By the way...the torque rods went in easily. Just jack up the rear end and take one out and replace it...then do the other side.

What you're describing sounds like the most glaring handling fault of all live-axle cars.

Any car with a live (solid) rear axle will exhibit this behavior to some extent. On a simple setup like the 240, it is more pronounced - on the more sophisticated 700/900 'Larsson' axle, it is more subtle.

The problem is that the rear wheels are rigidly connected to each other, and the axle is located laterally by a Panhard rod which swings in a slight arc through the suspension travel. The variable loading of the suspension through the bumpy curve (cornering and impact absorbtion combined) causes lateral jiggles in the body. Then the impact experienced by the bumped rear wheel perturbs the remaining rear wheel, possibly to the extent of breaking traction momentarily. This is what you feel when the car sidesteps in a bumpy corner.

The solution is a multilink rear suspension, but that's not really feasible for the 240. Your best bet is a good set of shocks (Boge Turbogas should work well, if not try Bilstein) and possibly a set of progressive springs.

The 240 is pretty well-sorted for a live axle car - try that same corner in an 80's-era Mustang and see how terrifying it CAN be!

On my '87 I replaced trailing arm bushings and torque rod bushings. Prior to the bushing replacement, the rear differential was actually bouncing and moving around. I have a manual transmission, and any time that I tried to start a bit too quickly, I would get significant wheel hop. The rear end just bounced around and created some horrible noises. With new bushings the rear end stays planted much, much better and I can now squeal the rear tires easily without them hopping around. Right now I have new bushings and old, worn shocks, so I would have to say that your problem is with the bushings.

Good luck.

Ben,

Getting the rear axle under control on rough roads was a major challenge on our rally car. First efforts were ipd overloads with Boge shocks. Not too good. Then Turbowagon springs with Bilstein shocks. Better. Final solution was a set of custom wound springs (same rate as ipd sport springs but 2" taller than stock (thanks Scott)) and a set of custom valved Bilstein's. They were set for +15% on compression and +25% on rebound. Bilstein will revalve any of their shocks for about $15 per shock. the folks at www.shox.com will sell you the shocks and send them over to Bilstein for modifying. Bilstein will not sell retail.

Admittedly, our application is extreme but like they say, "Racing improves the breed". Usually, the solution to a dancing rear axle is better shocks, not stiffer springs.

Skip

'80 242GT ProRally

'93 850GLT

I once had a 15-year old 140 Volvo (rear suspension similar to 240)that started to do this around 150K miles - it had good shocks(Koni)but all the rubber bushings were original. My 240 cars, which have new bushings on the rear axle) don't do this. Hope this helps.