How to change the rear suspension bushes.

Here is a description on how to change the rear suspension bushes on a RS Cosworth regardless of model because the rear suspension is basically the same on all models. Just a few minor changes that won't affect the procedures described here.

One thing to note before one starts is that putting everything back together with the new bushes is a breeze compared to getting the old ones out

  1. Jack the car up in the air, preferably with a lift that lifts it so high that you can stand underneath it and work. It will make things a lot easier.
  2. Remove the rear wheels.
  3. Remove the exhaust system. Itis best to remove all of it behind the downpipe from the turbo, because there it is a coupling that will loosen easily.
  4. Remove the propeller shaft, that comes from the gearbox, from the rear diff. This might not be necessary, I think it will go just as good without removing it.
  5. Start on the rear beam (one side at a time only). The beam is secured on each side by a bolt that goes through the large bush into the chassis and 2 smaller bolts that hold the plate on the bottom of the bush.
  6. To remove the bush; put a big socket between the chassis and the bush (and something on top of the socket to protect the chassis) Then jack the beam up towards the chassis and the bush will pop out. It will pop out easier if one uses WD-40 or something to lubricate the bush where it sits in the beam.
  7. Remove the bolts that holds the trailing arms (one arm at a time here too). The arms will drop down enough so that one can see the bushings. The original bushes are very hard to get out, I used a lot of time on especially the outer ones. The reason for this is that they have a metal outer outer casing which are pressed into the metal trailing arms with a hydraulic press. There are a few different methods one can use to get them out. I think the easiest is to remove the entire arm from the chassis and press them out with a hydraulic press. If that isn't available then a gear-puller will maybe do the trick. I got both the inner bushings out using a gear puller. On the outer ones though the center of the bush popped out and left a thin metal casing that I had to saw through with a hacksaw to get out.
    It might work better to heat them with a gas torch and hammer them out but that I haven't tried as I don't have a torch. When using the heat method be sure to protect the underside of the car, the fuel lines etc so things won't go pear-shaped.
  8. If you used the remove-by-heat method, wait for the parts to cool down.
  9. Coat the new bushes with lots of the supplied grease and insert them into the trailing arm. Fit the trailing arm into the slots on the rear beam and secure it with a new inner bolt (supplied)and the old outer bolt, and two new locking nuts. Tighten to specified torque.
  10. Insert the new BIG rear beam mounting bush into its seat with lots of grease so it will slip in easily. A way of doing this is to jack the bush into the beam while putting a piece of wood between the beam and the chassis. If you, while trying to locate the bolt that goes through the big bush, find that the beam has come misaligned during the process put a screwdriver through the bush and into the hole in the chassis and lever it into place. Fasten with the bolt that goes straight through the bush and the two smaller bolts that hold the plate on the bottom of the bush. Tighten to specified torque.
  11. Do the other side of the car in the same way as described above.
  12. Fasten the propeller shaft to the rear diff, and tighten bolts to specified torque.
  13. To replace the rear anti-roll-bar-bushes: Remove the to bolts that holds each bush, remove the old bush, coat the new bush with grease and fit it to the anti-roll-bar. Fit bolts and tighten to specified torque.
  14. Refit the exhaust system, preferably with new rubber mounts, or mounts made of the same sort of polyurethan used in the suspension bushes. The old one must surely need replacing anyway ?
  15. Check that you have tightened all the bolts and fitted all parts correctly. Now is a good time to find out that you didn't, not later when driving...
  16. Refit wheels and tighten to specified torque.

It is a good idea to have all your suspension angles checked when new polyurethane bushings have been installed, the old bushings may have been so worn that when changing to new ones the suspension alignment gets poor. On the rear of the car the bolts that hold the rear beam in place also controls the suspension alignment.

Tightening torques will be here soon:

 Rear beam mounting bush center bolt to chassis   68,5 - 88 Nm
 Rear beam mounting plate bolts to chassis   41 - 51 Nm
 Trailing arm inner pivot bolt   80 - 95 Nm
 Trailing arm outer pivot bolt   80 - 95 Nm
 Propeller shaft to rear diff   57 - 67 Nm
 Wheel bolts  100 Nm

Here's the reason it took me so long before I got around to changing the rear suspension bushes.


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