A week or so ago, I started to notice a rattle coming from the rear end of my E39. I knew I had a few things loose in the boot, so initially suspected it was just something back there moving around. However, after tidying things up, the noise persisted, and the other day I got underneath the car to see if something like a sway bar link had broken. To my surprise, I discovered this.

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I had no idea the coil was in such poor condition. There was no mention of anything when I had it MOT’d in July, and when I most recently inspected it, probably in early autumn, it looked fine, save for some of the coating flaking off. On top of all this, I hadn’t noticed any difference in how the car drove.

But what to do at this stage? Euro Car Parts wanted £49.99 for a Sachs coil, and wisdom dictates that they should be replaced in pairs. And given I don’t have a spring compressor, I would have to buy one of those as well. My heart sank even further when I looked up a tutorial on swapping the struts and coils and realised how much work it involved – more or less requiring that half the interior be removed. At this point, I must confess that I very briefly considered selling the car as spares or repairs just to avoid dealing with the problem. But after some searching on eBay, I found a very lightly used pair of struts and coils from a breaking E39 for £55, and so decided to dive into the project.

The first step was removing the rear seats, parcel shelf, and trim, in order to access the strut mounts. I expected this to be the most difficult part of the job, but using the helpful tutorial I found here, I had everything out and the mounts exposed in 30 minutes.

Once I had access to the strut mounts, it was a fairly straightforward job, again, using a helpful tutorial I found here. First, I removed the 13mm nuts holding the strut mount in place.

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Then I removed the 21mm bolt securing the strut to the hub.

Now, unfortunately, it was not as straightforward as simply removing the bolt and pulling the strut out, and I needed to make some room to get the assembly out. That meant, first, removing the inner lining from the wheel arch, and on the offside rear, the upper portion of the fuel filler neck.

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Following that, I needed to disconnect a few pieces of the suspension to be able to move everything around enough to get the strut out. I suppose there are a number of options here. I could have removed one of the upper control arms (as they’ve done in this photo), but I didn’t have the right size spanner for that, nor did I think the ball joint would survive removal (I have plans to replace those later on). So I decided to remove the bolt connecting the hub to the trailing arm, as well as the sway bar link. The trailing arm bolt head is 18mm, whilst the nut is 24mm. The sway bar link is connected with a 17mm nut.

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This gave me some room to play with in order to be able to push the trailing arm down far enough to remove the strut. I had my wife help at this stage, as it took quit a bit of force to push the trailing arm down, and I wasn’t able to simultaneously do that and wiggle the strut out. A decent pry bar might have helped. At any rate, here is the empty wheel arch with the strut removed.

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For the sake of comparison, here are the old and new strut and coil assemblies.

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To install the new strut and coil assembly was fairly easy from this point. I slid it up into the mounting holes on the body, and again had my wife help by fastening one of the 13mm nuts, just to hold it in place. Then I reconnected the trailing arm, as it is impossible to do if the strut is mounted to the hub (believe me, I found out the hard way). The long trailing arm bolt gets torqued to 189 lb.-ft. I then refitted the strut mount to the hub, and began to torque everything down. The 13mm nuts on the top strut mount get torqued to 20 lb.-ft., and the 21mm bolt on the bottom to 94 lb.-ft.

The most frustrating part of the job was refitting the wheel arch lining. It took a bunch of pounding with my rubber mallet to get it fully back into position. Once it was in place and refastened, the job was done. I lowered the car, bounced it a few times to make sure everything was seated properly, and put the interior back together.

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Normally, replacing something like struts and coils should be done in pairs. Due to time constraints, I have violated that rule, but I did a thorough inspection of the coil on the other side, and it is not about to go anytime soon. After Easter, when life has calmed down a bit, I’ll tackle the other side – unless it breaks before then, of course. For now, I’m happy to say that a quick test drive has confirmed a successful repair.

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4 thoughts on “Replacing the rear struts and coils on a BMW E39

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