E34 Steering & Suspension Upgrade

It’s been some time since we played with Project 46, our black E46 330Ci M Sport project car, so we thought we would fill the void and bring you something a little different this time. It’s no secret that we’re pretty big BMW enthusiasts, and that definitely includes some of the older and lesser-known models. One such BMW is the E34 535i, which is a bit of an underrated driver’s car in our opinion. By today’s standards it’s not at all that fast, but in late 1988 it was certainly well beyond its time, being one of the quickest and most luxurious sedans available anywhere in the world.

At the time reviewers commented on the excellent build quality, comfortable ride, and beautiful handling of the 535i. Its only real downfall was the recirculating ball steering, providing lacklustre feel and weight to the driver. These days, that poor steering response is only exacerbated by old and loose suspension components. Considering most E34s still on the road now have quite high mileage, it’s very common to find the bushings and ball joints in the front of these cars have completely worn out. This can lead to a significant amount of steering play, along with shudders, shimmies, and all manner of odd reactions when the car travels on our typically poor Australian roads.

In late 2014 we travelled to Frankfurt, Germany to visit a number of our current suppliers, as well as seeking out some new relationships. One range of suspension components we were particularly impressed with was Bendix by Honeywell. Most people in Australia know Bendix for their range of brakes, but it's worth mentioning that the Bendix branding has nothing to do with the brake company, other than a licensing agreement. The parts are actually made by another very well known suspension manufacturer and simply packaged as a Bendix part by Honeywell.

Over the past six months, we’ve been trialling Bendix suspension to see whether it’s something we want to add permanently to the Clickable store. We continue to be impressed with the quality and value of the parts, but we’re not yet certain if there is a place for Bendix suspension parts in the local BMW community. We’re looking forward to receiving feedback from our customers who have fitted these parts before we make a decision on its future.

One of our mantras here at Clickable Automotive is that we will only ever offer parts that we would be happy to fit to our own BMWs. With the steering and suspension of my personal E34 535i gradually worsening, it seemed like a good time for a major front-end freshen up, as well as taking the opportunity to upgrade a few components to compliment the Bilstein B6 shocks previously fitted to the car.

With the steering and front suspension components dropped out of the 535i, we discovered the car had already been fitted with polyurethane bushes in the upper control arms. Poly bushes are an attractive modification as they are generally cheap and offer good longevity, as well as improving handling and feedback. Although suspension is entirely subjective, when poly bushes are fitted to the upper control arms (especially those that take much of the brunt from potholes as they do in the E34), they can change the character of the car dramatically. As well as detracting from ride comfort, these hard bushes would have transferred greater stresses onto other suspension components, amplifying the rate of wear and generally making the problems worse. This was particularly evident on the tie rod ball joints, which were well overdue to be replaced.

A brand-new Bendix centre steering rod (drag link), Bendix tie rods, and a Meyle idler arm were all bolted together and lifted into the car and reattached to the pitman arm, along with Bendix sway bar links. Rather than going for standard control arms, we decided to borrow some upgrades from BMW’s own engineering department. The new Febi-Bilstein upper control arms had E32 750iL bushes pressed in, which use a harder rubber compound than the originals, improving the 535’s handling while still maintaining its trademark BMW ride (or in this case, restoring it).

For the lower control arms, it was an easy choice to go with the E31 8 Series versions which are an improvement in every way. Firstly, these are fully aluminium, providing half a kilo of (unsprung) weight saving over the original steel arms, which contributes to improved ride, handling, and braking. The E31 arms also have spherical bearings in place of the rubber bush, allowing almost zero movement -- even less than polyurethane bushings. However, unlike the poly bushings removed earlier, these bearings are mounted ahead of the front wheels and don’t take the full impact force over bumps, simply improving feedback and steering without disrupting the ride comfort. Finally, the ball joints in the arms are designed to be used with the heavier V12 motor of the 850CSi, so they’re a lot stiffer than the original ball joints that came on the E34. A big plus with these upgrades is that they bolt straight in without any modifications, utilising the original suspension geometry. But the best thing is that these parts were originally designed and tested by BMW and released on their flagship models.

When bolting in the control arms, the suspension was placed under load before the nuts were tightened to ensure the stress transferred from the road is directed through the rubber bush correctly (though it wasn’t necessary for the spherical bearing of the lower control arms). One way to achieve this is by driving the car up onto ramps so you can still get access to the underside.

We took our time doing this job, removing the old components over the course of a lazy Saturday and fitting the fresh parts on an equally lazy Sunday. Anyone with the right tools and basic mechanical knowledge could finish the job on their own in a day, though it’s worth mentioning that the car will need a professional laser wheel alignment after it’s been finished.

With the entire front-end back together, we hit the road in the 535i and discovered the car had been completely and utterly transformed. Steering went from a significant amount of slop between 10 and 2, to fairly minor play between 11:45 and 12:15 (the usual amount for an old recirculating ball). The heavy-duty ball joints in the E31 control arms combined with the brand new steering components have significantly improved the weight and feedback through the steering wheel. This now allows the car to be placed far more accurately on the road, particularly when pitching it into a corner and following an apex. Despite pads and rotors that are about due to be replaced, braking performance was still improved noticeably as the suspension was no longer taking the slack at initial bite. The car also thankfully became less harsh with the new bushes installed, with no discernible difference in handling. Coupled with the Bilstein B6s, the front end now steers and handles better than it ever did from the factory, but still retains its quintessentially BMW ride. Despite the steering remaining the weakest part in the car, replacing all of the components has improved it dramatically. The front-end refresh has breathed new life into the beloved E34, making the car both a lot safer and a lot more enjoyable to drive.

New Mechanical Repairs:

Front Upper Control Arm - Left - $75

Front Upper Control Arm - Right - $75

Sway Bar Link - Front - $25 x2

Front Centre Rod Assembly - $89

Aluminum Front Lower Control Arm - Left - $199

Aluminum Front Lower Control Arm - Right - $199

Tie Rod Assembly - Front - $39 x2

Idler Arm - $29

Total Cost of Repairs: $794