BMW E36 refurb

In the final episode of this three part series, we tackle our BMW’s worn rear trailing arm bushes and discover a nasty bit of grot that required the attention of an expert welder

Our BMW is back in the workshop to sort a fault with the rear suspension.

Last month we left off with the BMW’s front suspension and brakes finally being renovated. The new backplates, springs, bumpstops, ABS sensors and overhauled wishbones were all installed and everything cleaned up and repainted. The rear end on these cars is a bit more involved and whilst many E36 restorations of models such as the M3 and 328i Sport will involve dropping the rear axle before tackling a full strip down and restoration, but we’re not going that far.

We are, however, going to be replacing the tired old dampers, along with a broken top mount, utterly ruined rear trailing Z arm bushes and refitting the original rear springs. The car has been on Eibach lowered springs for a couple of years but as good as these are, the ride height was too low for our ever deteriorating roads and ageing bones.

The springs that came off the car were all very rusty, but we’d bought a set of original BMW springs from a low mileage 318i a while ago that was having Eibachs fitted. The originals on that car were in really nice condition, so these have now gone on ours.

Fitting new trailing arm bushes can be a horrid job and you may, like us, find some rot in the ‘cups’ in the floor where the brackets sit. The symptoms of worn bushes are a wandery feel to the back end of the car and in our case, the odd knock as the arm went sideways and fouled the steel bracket. However, these were the original factory bushes and they have done remarkably well.

Our driver’s side was rusty but solid but the other side had holes that had been welded up before we could get any photos! Ideally, rusty examples like on our car will require some work. At the very least, buy new through bolts and nuts from BMW, as the old ones will be very rusty – ours were a swine to remove too. Either way, all E36 owners should now unbolt their trailing arm brackets to see what’s happening – you never know what’s lurking in there.

Just one point worth mentioning and that’s about the three 18mm bolts securing the trailing arm brackets to the rear floor. It’s not unknown for these to snap off in the body, so make sure the car is parked up somewhere where it won’t be in the way. The bolts are not hardened, but even so, they won’t be easy to get out.

After everything was put back together, a quick run revealed just how well the cars drives. It’s now got nice precise steering, a well damped ride and nothing to indicate that it’s 20 years old with over 180,000 miles on the clock. Now that all the mechanical work is out of the way, for the time being the final job will be to give the car a good valet inside and out and start enjoying it again. Here’s what we’ve been up to in the final episode.

1 Removing the rear damper lower mounting bolt from the trailing arm allowed the arm to spring down a couple of inches, but not with any real force. Next, we undid the bolts securing the brake pipe bracket to the trailing arm. When refitting the arm, jack it up to normal ride height before applying a dab of thread lock and torquing the bolt up to 100nm.

2 After the three 18mm bolts were removed, the bracket was pulled down and revealed one of our 20-year old E36’s utterly knackered trailing Z arm bushes. These bushes have alloy sleeves and there’s no way they will come out in one piece. You have to somehow prise the rubber centre out first and then remove the remains of the alloy outer sleeve afterwards. But there’s an easy way…