Rear Suspension:                                                                                               FAQ Home

Volvo Maintenance FAQ for 7xx/9xx/90 Cars                                                                                                                     Version 5.0

 
Rear Bushings

Vibration from Solid Rear Axle

Rusted and Stuck Bolts: Removal Techniques

Rear Spring Replacement

Rear Shock Installation

Rear Nivomat Conversion



Rear Bushings. [Symptom:] When you accelerate from a stand still or when you decelerate suddenly, you could hear and feel a jerk from the rear. This is when the rear suspension is beating the chassis as it is taking up the clearance due to the worn bushing. [Diagnosis:] Try this: Jack up the rear end of the car and first with the car in neutral and the park brake off, turn the drive shaft back and forth quickly. You will see if there is much play in the torque arm bushings. The rear end will actually swing back and forth. With the weight off the rear end, you should be able to pry on various portions of the trailing arms close to the bushings and notice if there is excessive play. If your trailing arm bushings are bad, you'll need a special tool to take them out and press them back in. The torque arm can easily be taken out and the bushings pressed in and out.

"Clunk" in Rear End: Bushing Diagnosis.  [Query:] 87 740 wagon with 190k, M46 trannie, new to us. Have replaced shocks, struts, u-joints, trannie mount and center support bearing on driveshaft, and some front bushings. Acceleration from standstill in normal traffic results in a "clunk" which seems to come from rear end.  Trannie output bushing and pinion bushing have no play. Wheel bearings are good. Nothing is rolling around in rear of car or spare tire well. The only thing I can figure is bushing(s) in rear, but which one(s)? (none are visibly broken up, although I haven't yet given them the prybar test.)  Can anyone guide me to the most likely culprit on this one?  [Response: Steve Seekins] I would focus on the rear suspension bushings. There are 7 - two on each of the torque rods and three on the sub frame to body mounts - one at the front and two at the rear. I would suspect the subframe mounts, probably got accelerated wear from soft torque rod bushings. The Haynes manual is adequate for procedures here.  Of course you should first check for loose upper or lower shock mounts or loose sway bar mounts. If the lower shock mount has loosened, check carefully for elongated hole in trail arm - if so, consider replacing the trail arm if tightening the bolt does not do the job.


Vibration from Solid Rear Axle. My 745 with a solid rear axle has a single arm with large rubber donut bushings connecting the underside of the differential to the frame just ahead of the diff. The lower rubber donut has gone really soft, allowing about 15 degrees of angular rotation of the rear axle; enough to seriously deflect the drive shaft under acceleration at low speed and causing the U joints to grumble loudly. At speeds over 15 kmh the noise is gone; I suspect the momentum of the drive shaft resists the deflection and the acceleration force is lower. The side bushings are fine; also I have a heavy IPD swar bar.


Rusted and Stuck Bolts: Removal Techniques.  See the link for more ideas.

Rear Spring Replacement. [Query:] I am thinking about installing new springs and shock in the rear of my 745. How do I do it?] Regarding putting together a detailed procedure for REAR spring replacements on a 745, basically anybody who knows which end of a ratchet is which can do it. This is one of the easiest things I've done to that car. It pertains to 7xx wagons with "live" (aka non-IRS) axles. Probably pertains to the sedans, too. A brief note: For replacement springs on a wagon, I recommend going with "cargo coils", which are variable rate springs. I purchased a set of MOOGs from my local parts supply (about $70 w/tax, as I recall) and have been quite happy with them. I have had a couple of occasions since installing them to give them a good try-out, the most severe being when I filled the entire wagon full of materials for a new section of fence, including post hole mix. I figure we had loaded about 800 lb. of stuff in the back, plus there were two of us adults. The springs handled this extra weight with ease. Further, because they're variable rate springs, they still offer a decent ride even when unloaded. [Contrary Note:] I recently installed a set of Moog cargo coils on the rear of my 89 765T and while I've been happy with the ride etc. I'm not happy with the sagging rear end they left me with. It sags about 1.5". I've talked with the reps at Moog and they say the cargo coils are for sedans only and do not have an application for wagons. I've ordered a set of IPD overload springs which incidentally list different part #s for 7xx sedans and wagons. RPR also sells Moog cargo coils for sedans only. In speaking with them they've had a lot of complaints of rear end sag when used on wagons


Rear Shock Installation.  [Query:] I am thinking about replacing rear shocks on my '89 745 Turbo Wagon (non-Nivomat) and would like to know how difficult a job this is [Response 2: John B] The shocks ARE gas charged and can be difficult to compress and remove...same with the new shocks. IF the new shocks have a wire or strap to keep them compressed, try to install them with the wire or strap unbroken...you clip the retainer device to allow the shocks to expand and hit the stud hole for the top of the shock.  Also, the lower control arm that the shock goes into may be tight or loose depending on the brand of shock you buy. If it's loose, make sure you tighten the bolt sufficiently to compress the control arm sides against the shock bushing...or the shock will clunk. If the shock bushing is too long, making the shock impossible to install, just wedge or expand the control arm sidewalls enough to put the new shock in. Jack the back of car up and put it on stands. [Response 2: Bill Woesthaus]  Take wheels off. Pull the rubber bolt hole cover off the top of the inside wheel well. Unscrew the top shock bolt. Then, put wrench and socket on bottom shock bolt, undo it. Wrestle shock out. Compress new shock and put it in, top bolt first then bottom. Itís a good idea to leave the retainer wire on shock  (you don't have to wrestle with live shock)  Possible trouble? Top shock cavity could be too bent in from heavy bolt pressure to allow new shock in easily, or to get old one out!! I ground down shock ears to allow entry. If your holes aren't squashed tight it's a pretty easy job.


Rear Nivomat Conversion.  See  Volvo 760/780 Nivomat Shock Conversion for complete instructions and illustrations showing the conversion of Nivomats to normal springs and shocks.

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