Knocking on rear suspension.
 

Anybody else have problems with the rear suspension on a 240 estate.
I have changed, trailing arms, all solid bushes, shocks and heavy duty springs.
Every time we drive on a bumpy road the rear of the car sounds like it bottoms out with a thud. This is with no weight on the back of the car. Does anyone have any ideas. Could it be that the shocks and springs aren't heavy duty enough? Thanks Mike

I would suggest getting a serious look underneath. Traditional techniques. Including levering just about everything.

Is the exhaust knocking the body?

This might be a total red herring. But. I had similar noises on a 740. On that car there was some sort of stabilising link arm from the bodywork to the diff. The bolt securing the arm to the diff had sheared off. Had to be drilled out. Bovver.

Good luck.


.

Possibly the bump stops have perished. Or, as Steven Edwin suggests, there's a loose/failed component that's allowing the axle to bounce off the floor pan.

Whatever it is, you're going to have to get underneath and inspect everything.

Have you checked the reaction rod bushes? They have a short life in my experience, only about 40,000 miles, but are fairly easy to replace. At least you can unbolt them and replace the bushes on the bench. I keep a spare pair with new bushes ready to go, and then its just a few minutes work to swap them over. My tip is only to remove one rod at a time, to keep the axle roughly located.

They are two horizontal rods running forwards from the top of the axle casing, bolted to the chassis side members, about 2' long.
If the bushes have gone soft then the axle can swing round under torque, causing the nose piece of the diff to hit the bump stop.

Thanks for the replies.
I have had the car on a ramp and the exhaust isn't touching the car.
The bumper stop on the passenger side is missing, but the other side is good but i don't think it is being hit.
The anti tramp bar from the axle to the body bushes have been replaced with polyurethane bushes. I fitted new trailing rubber bushes but after a month there was to much play in them so I fitted new polyurethane ones. All the bolts have replaced. Been out this morning and it just seems to thud from both sides independently when going over a bumpy road. I can only think its got to be the new shocks and the springs aren't strong enough. The shocks are Bilsteins, just think I should get more expensive ones to see if that helps. Thanks Mike

A long shot if all the other advice checks out: ~

Have a look at the shock absorbers and the amount of travel that is available—if the suspension is at its highest point some of the above top out- i.e. no more upwards travel is available, always worth checking the same when purchasing replacement items (they can differ)
If work is carried out on the rear particularly if spacer adjusters have been fitted for towing it can happen—an easy test would be to put some weight into the boot and road test.

May also be worth checking the front suspension control arm bracket, I had a loose bolt once that took some tracking down!
Springs ok?

Good Luck
Bob.

Thanks for your suggestion, I will take the car out and check the old shock lengths with the new. But i think the thud is more on compression, but I will try it with some weight in the back. Thanks Mike

It may not be relevant but beware that a fully poly bushed suspension can give rise to much more in the way of nasty thumps than standard rubber bushes.
Not quite so relevant with poly, but fully tighten everything with the wheels on the ground. A full tank of petrol is a good idea too. Hopefully the polys are properly greased. Torque settings have to be high enough to make the inner sleeves hold TIGHT.

I had a clanging, thumping noise on the rear of our Torslanda with brand new Bilsteins which I purchased from PFV. I changed the shocks over to Sachs and the noises disappeared and the ride improved. Strange, the Bilsteins almost seemed to be too hard for our family hauler. I've now got some Bilsteins in the loft if anybody wants some near new ones..
Chris

How much do you want for them? I might be interested.