There is no definitive answer for how long a suspension component should last, but when your car regularly deals with rough roads, road salt, and other stressors, it is no surprise to find parts beginning to wear out around 50,000 miles. I bought my E39 in the autumn of 2015 with 54,000 miles on the clock, and it needed new tie rods up front. Since I had it apart, I also did the traction arms, control arms, and anti-roll bar links at the same time. A couple of months ago, at 68,000 miles, I replaced one of the rear strut and coil assemblies, and noticed at that point a split boot on the rear control arm. A creaking sound from the nearside rear also indicated a bad ball joint, which you can see below.
— Jake Belder (@jakebeldercars) May 29, 2017
So, as I still needed to replace the other strut and coil assembly, I set out to install new controls arms, ball joints, and anti-roll bar links in the rear as well. This post details that process. (Note: These instructions apply to the E39 saloon. The setup is slightly different for estate models.)
Here you can see, first, the setup of the nearside rear suspension. The two control arms mount to the subframe, and attach to the top of the wheel hub. An integral link connects the hub to the control arm, with a ball joint at one end pressed into the hub. In the second photo, it is the control arm on the right that has the damaged boot.
Beginning with the car on the ground, measure the distance from the wheel centre to the top of the wheel arch. On my car, this was about 14 inches. Take note of this measurement, as you will need it later on. Then raise the car and remove the wheels.
The suspension overhaul begins by disconnecting the strut from the hub. This is attached with a 21mm bolt, and it will be extremely tight. Use lots of patience, and a long-handled ratchet with an angled head or a flex joint. Once it is loose, push the strut back out of its mount. Do so carefully, as the whole hub assembly will move up once the strut is loose.
Next remove the long bolt that passes through the lower control arm, integral link and ball joint. Get a good breaker bar for this one – the 24mm nut is tightened down to nearly 200lb.-ft. Once it’s off, tap out the bolt, and lift the hub assembly up to rest on the lower control arm.
Next, remove the integral link, which is attached to the hub with an 18mm bolt.
Now it is time to remove the ball joint. This will probably be the most difficult part of the job because it is pressed in, and given its exposure to road salt and the elements, things will feel like they’re welded together. Clamp the hub and lower control arm together with a pair of vice grips. Then, using a chisel, begin to pry the snap ring away from the hub. You’ll need a lot of patience here as the ring rusts to the carrier, but if you start at the opening and slowly work your way around, it will eventually come free.
Once the snap ring is off, remove the rubber boots from both sides of the ball joint, and then you can press the ball joint out. Owing to the unique design of these ball joints, you will need a special tool to remove them. These can be quite expensive, but I found one on eBay for £25 (if you check the forums, you will also find some DIY solutions that involve big C-clamps). As you can see in the photo below, it uses two cups, one to push, and one to receive the ball joint. The offside ball joint popped out easily, but the nearside required lots of 3-in-1, and me throwing all my weight onto a breaker bar. But in the end, it came out cleanly. After you remove the ball joint, use a wire wheel attachment with your drill to clean out the carrier in preparation for the new ball joint.
Now you can remove the upper control arms from the subframe. First, mark the position of the bolt on the control arm that sits towards the front. This is the toe adjustment for the rear-wheel alignment, so you need to ensure this remains as close as possible to the original position. Then remove the bolts from both control arms. Removing the 16mm nut from the toe adjuster bolt is not easy, as it’s in a very tight space. If, like me, you don’t have long-handled spanners, hook another spanner on the end of your 16mm spanner to get leverage to remove the nut. The other control arm uses an 18mm fastener.
Now you can remove the control arms from the hub. Should you be blessed with extraordinary patience, you can try and remove the 21mm and 17mm nuts that are inevitably welded to the hub. Even if you do manage to break the nuts loose, the ball joint inside the arm will spin with them, so I recommend just cutting them off with an angle grinder. I have marked below where I cut – on the front arm, right up against the hub, and on the rear arm, next to the washer that sits between the nut and hub. Go ahead and cut the anti-roll bar links off at the same time. I had the benefit of having the strut and coil assembly out at this point; if you don’t, it will take some careful angling with the grinder to get at the lower anti-roll bar link mount.
Make sure you place a brick or some other sort of support underneath the hub at this point to avoid pulling on the CV joint and the brake line. Now that everything is removed, reassembly can begin.
Begin with the anti-roll bar links, and then attach the new control arms to the hub. You could attach them to the subframe first, but this makes it more difficult to move the ball joint ends into position.
Next, resting the hub on the lower control arm again, press the new ball joint into place, and fit the new snap ring. Getting the snap ring on takes patience, but work it around carefully with a flathead screwdriver, mindful of the rubber boot, and it will seat properly.
Fit the new integral link, and fasten the upper bolt to the hub. Then lift the whole hub assembly and carefully slide it between the two ends of the lower control arm, as the ball joint boot will tear easily if it gets caught on the control arm. Once it’s in place, reinsert the long through bolt.
Reattach the upper control arms to the subframe. Then push down on the hub assembly and refit the strut.
Finally, preload the hub by putting a jack underneath and raising it normal ride height, using the measurement you took earlier. Then begin to torque everything down, using the following torque specifications:
Anti-roll bar links: 47lb.-ft.
Lower strut mount: 94 lb.-ft.
Toe-adjustment arm: 44lb.-ft. (subframe), 48lb.-ft. (hub)
Other upper control arm: 81lb.-ft. (subframe), 105lb.-ft. (hub)
Integral link to hub: 77lb.-ft.
Lower control arm through bolt: 188lb.-ft.
There is a problem here, though. Unfortunately, even with those specifications in hand, you will immediately realise that you can only get a torque wrench on some of the fasteners. I believe you can buy torque spanners, but I don’t have any, and so in the end, simply had to rely on feel when tightening a few of the fasteners. It’s not ideal, of course, but it was the best I could do with what I had.
Generally, replacing these parts means the geometry of the rear suspension will have shifted, and an alignment will be needed. The easiest way to do this, of course, is to bring it your local garage, but if you’re feeling brave, you can also do it at home with guides like this. The only thing I briefly checked after putting the wheels back on was the toe, by placing a straightedge across both wheels and measuring at the front and rear. To my delight, the measurements were exactly the same, indicating the wheels still point straight, and meaning it will probably only need minor adjustment.
Overall, save for the difficult ball joint, a suspension overhaul on this car is not a very difficult process. Basic hand tools are all you need to accomplish the work, and parts are reasonably priced. Set aside a few hours for each side, and you will once again have an E39 that drives and rides as it should.