The BMW E39 5-Series is one of the most popular iterations of the executive sedan that the German manufacturer has ever produced. So much so that it would feature on Car and Driver magazine’s “10 Best list” for six consecutive years — from 1997 to 2002. For a car that was in production from 1995 to 2004, that’s mighty impressive. At the time, Consumer Reports would also award the BMW 530i its highest car rating as the best car they’d ever reviewed.
The prowess of the BMW E39 5-Series is not to be questioned. It’s a car that got a lot of things right. Overall, the E39 5-Series was a hugely reliable machine, but as you may know, no car is perfect. One of the more severe issues you may experience with a high-mileage model from this generation of the 5-Series is the thrust arm. The E39 thrust arm bushing is one of the few caveats in the car’s unproblematic build.
In this article, we’ll cover how you can spot a faulty thrust arm bushing and how you can go about replacing one by yourself.
What Is a Thrust Arm Bushing for a BMW?
The thrust arm bushing on your BMW is responsible for controlling the movement of your front wheel with respect to the suspension. Without a properly functioning thrust arm bushing, the front wheels of your car will wobble back and forth under acceleration or braking. Simply put, your E39 thrust arm bushing keeps the suspension in line with your front wheels when the car is moving.
The BMW E39 5-Series has a slightly sophisticated front suspension assembly. It features two control arms with a MacPherson strut attached to it. The upper control arm is the longer of the two and is referred to as the thrust arm. Its primary function is to mitigate the effect of longitudinal forces on the front wheels.
You can easily spot a thrust arm bushing by looking for a rubber cylinder enclosed in an outer metal sleeve with an inner metal shaft. This bushing is filled with hydraulic fluid.
What Causes a BMW Thrust Arm Bushing Failure?
An E39 thrust arm bushing is subject to continuous wear as it’s constantly working to keep the front wheels in line with the suspension. How quickly they wear out can depend on several factors, including driving conditions and how aggressively you brake or accelerate. Typically, they should last between 60,000 and 120,000 miles.
You might have to replace the thrust arm bushing sooner if it’s subject to physical damage. A cracked bushing can cause the hydraulic fluid to leak and reduce its efficiency. This can also cause mud or debris to get stuck in the bushing.
What Are the Symptoms of a Faulty E39 Thrust Arm Bushing?
Any issues with an E39 thrust arm bushing will be noticeable immediately as they are crucial to the regular operation of your car. Other problems with the steering or suspension system could also be the source of the symptoms mentioned below. As such, the only way to be sure that a thrust arm bushing problem exists is to visually inspect the component and look for wear or damage.
If you encounter any of the following problems while driving, your E39 thrust arm bushing may need to be replaced:
Inefficient Brakes
The thrust arms connected to the front-end suspension ensure that the wheels don’t wobble when you’re on the brakes. With a faulty thrust arm bushing, you’ll notice that the wheels move unnaturally under braking, reducing how efficiently you slow down. This symptom will only worsen in time, so it should be addressed as soon as you notice it.
Steering Wheel Wobble
Another issue you’re bound to notice immediately from the driver’s seat is steering wobble. Apart from wobbling while driving straight, a worn-out thrust arm bushing may also cause your car to veer to one side, even when there’s no driver input. In more severe cases, an external observer will also be able to notice the dramatic shimmy at the front wheels.
Clunking on Stops and Starts
If you hear a loud thud or a concerning clunk when you go over a bump or come to a halt, there could be problems with the thrust arm bushing. When the bushing is worn out excessively, it can move around, making a loud noise.
Front Tire Inner Tread Wear
The wheel to which the control arm bushing is attached may induce a wobble when worn out. This alters the wheel’s regular alignment, increasing wear on its inner edge. This uneven wear on the inner edge is referred to as cupping.
These symptoms may also be caused by a wheel alignment or balancing issue, so it’s best to check those before replacing the thrust arm bushing.
How to Replace an E39 Thrust Arm Bushing?
Replacing a thrust arm bushing will require some specialized tools. If you have access to them, you can take a few different approaches. The first would be to replace the thrust arm entirely with a replacement part from BMW. While this will add a new, reliable part to your car, it’s also time-consuming and will require you to dismantle the front suspension entirely,
Alternatively, you can replace the thrust arm with an improved part from a newer BMW. Again, this requires a lot of time and work and will only bring marginal improvements in performance and reliability.
The most straightforward option is to let the thrust arm remain and replace only the bushing. To do this, you will need a set of press/receive sleeves designed by BMW. With this method, the thrust arm is disconnected from the car, and the press/receive sleeves are used to remove the old bushing and insert the new bushing. Check out our offer of E39 thrust arm bushings for a quality replacement.
How Much Does It Cost to Replace Thrust Arm Bushings?
Replacing a damaged E39 thrust arm bushing can cost around $350, depending on the quality of the replacement parts you get. The BMW press/receive sleeve tools can also be expensive, so it’s worth considering only if multiple bushings must be replaced.
If you’re taking your car to a technician, it’s a good idea to ask them to check the entire suspension system, including the thrust arm bushing bolts and joints and lower control arms, to ensure that all of it is in properly working order.
Get Your BMW E39 Thrust Arm Bushing Now!
The thrust arm bushing on your car plays an integral role in its normal functioning, letting you enjoy a smooth ride and trouble-free handling. You’d be in serious trouble if they were not in working order.
At Bimmers.com, you can get your hands on individual thrust arm bushings or entire E39 suspension parts. We only stock genuine BMW or aftermarket parts, so you never have to worry about reliability. Simply head to the shop section, input your car’s data, and use the filters to find the needed part.
