RENEWING REAR DAMPERS

Start by removing this rear trim panel. Flip up the covers on both sides, as shown, to reveal a self-tapping screw that needs to be undone. There are also two plastic rivets securing the panel to the bodywork and these are easily removed, followed by the panel itself. It’s worth going over the area with a vacuum cleaner before reassembly. With the rear trim panel detached, the two side carpet panels can now be taken out. These just clip in and are simple to remove, but you’ll need to fold down the rear seats. On coupés, convertibles and E90 saloon cars, you just need to get the rear seats out of the way to access the rear damper top mounting nuts. There is a circular rubber cover to remove – just flip it out with a small flat-blade screwdriver. This reveals the top damper nut, a 16mm Nyloc that is tightened up to 27Nm on reassembly. The damper rod will try to turn when undoing this nut so use a small spanner (ours was 7mm, but some are 6mm) to hold it still as you undo the nut. This is the rear suspension layout on the 1-Series, a design BMW still use and which was also used on the E90 3-Series. It’s completely different to the previous Z axle set-up, but it’s still quite simple to work on. Our rear shocks were knackered – they’re rusty and you can see the fluid leak at the top of the damper. You need to undo and extract the two E12 Torx bolts securing the lower damper rubber mounting block in the lower suspension arm; these are tightened to 60Nm. Some manuals say the damper can be removed with the lower mount as a single unit, but 10 years of rust might make that difficult, so we advise you remove them separately.

This shot shows the lower suspension arm with the two Torx bolts removed, as well as the centre damper retaining nut that is torqued to 37Nm. The rear damper is compressed downwards in on itself – easy when they’re as worn as ours – and pulled up and out of the lower mount. With the damper out of the way, the old lower mount can be removed – it’s obvious which is the old one here! To be fair, it was still in good nick and could have been reused, but we took no chances. As you can see, there are retaining nuts welded to the mounts, but it’s wise to oil the threads and run the bolts through them before refitting.

Here are the damper parts laid out in the correct order – missing from this photo is the black plastic damper protection tube that fits onto the bump stop. The rubber boot on the far left is a protection boot and should be fitted into the car body first, followed by the damper raised up into position – using a smear of rubber grease is a good idea. The new Boge damper is held still while the lower retaining nut (fitted loosely here) is tightened up. Visible just below the damper body is a series of flats onto which you can fit a spanner– ours were 17mm, but they will vary from manufacturer to manufacturer and they’re very useful. This is the 16mm top retaining nut on the rear dampers. It has been fitted with an integral nut and a rubber buffer washer to prevent rattles. The new system of the lower rubber mount replaces the old system with the rubber top mount that was known to break up and cause rattling. Although changing the front dampers is a pretty difficult job, the rears are quite easy and take about an hour per side – the second one will take less time once you’ve had practice doing the first one. To prevent rust, a coat of Waxoyl will keep them looking good.