Bad Control & Trailing Arm Bushing Symptoms

Many of BMW's most iconic models feature an independent rear suspension that utilizes both control arms and trailing arms. These arms connect the rear hub and wheels to the vehicle's body/frame, using bushings as pivotal points for smooth movement and stability. At the BMW factory, the bushings installed in both the front control arms and rear trailing arms are made from rubber components designed to withstand a lot of pressure and movement. BMW utilized rubber to maximize comfort for everyday driving conditions. However, these bushings are prone to wear out over time due to their constant exposure to the elements, stress, and movement. This guide explores the symptoms indicating the need for replacement of failing or failed control arm and trailing arm bushings.

DIFFERENCE BETWEEN TRAILING AND CONTROL ARM BUSHINGS

Trailing arm and control arm bushings, while serving similar purposes in the suspension system by connecting suspension components to the vehicle's subframe, are distinct parts located in different areas of the vehicle. The primary difference lies in their specific functions and locations. Control arm bushings are primarily found in the vehicle's front suspension system, facilitating smooth movement and alignment of the control arms. Trailing arm bushings are specifically part of the rear suspension, connecting the rear axle or hubs to the vehicle's chassis. Despite these differences, the symptoms of wear or failure in both types of bushings can be quite similar, making it crucial to understand and recognize these signs early on.

4 SYMPTOMS OF BAD TRAILING ARM BUSHINGS OR CONTROL ARM BUSHINGS

1. KNOCKING  NOISES

Strange noises coming from underneath your car are probably the most common symptoms of failed arm bushings. The design of a factory-installed bushing allows for movement under stress and pressure, and the rubber keeps things quiet. As the rubber portion of the bushing ages and starts to deteriorate and fail, the metal parts come into contact with each other, and a clunking noise will start to develop. This symptom, often exacerbated by driving over uneven pavement or speed bumps, is a clear indicator of a bad bushing. If you hear any knocking noise coming from under your BMW, at low speeds or especially when driving on track, it's crucial to check it out and most likely replace it. Shame on you for running stock bushings on the track!

2. TIRE WEAR

Excessive or uneven tire wear can be another symptom of worn bushings. All bushings play a significant role in the suspension of a BMW, and when they start to fail, they can affect and add strain to many of the moving parts involved, especially the front and rear tires. As the worn rubber portion of your control arm bushing flexes, your car’s alignment will change. This change can be subtle or if you are on track it can be extreme. For street and track applications, proper wheel alignment is crucial, and worn bushings will destroy a set of sticky 200 treadwear tires on short notice. You should inspect your tires regularly, and every track car should also be inspected often, so alignment issues due to worn bushings should be easy to catch.

3. POOR HANDLING

Poor handling can be a symptom of many things but failed rear trailing arm bushings are a common culprit. The trailing arm bushings on a BMW are meant to articulate in multiple directions. They are one of the most stressed suspension components of the chassis. When they fail, it is very noticeable. If your bushings are worn enough, it can cause the rear suspension arms to move laterally from side to side. While driving this will feel like a steering issue. In this case, you might feel some looseness or slack in your car's steering wheel, but in reality, you are having to overcorrect for rear-end movement due to failed trailing arm bushings. If your steering system components, such as the tie rods and control arm bushings, look good, check out your rear trailing arm bushings!

4. OTHER FAILED BUSHINGS

Many drivers only replace their control and trailing arm bushings when they have failed completely, but there are other good reasons to go ahead and replace these bushings, especially if you're planning on hitting the race track. One of the best reasons to replace worn bushings is if you are already replacing another similar bushing. Many times other bushings are part of an entire system and if one needs to be replaced, most likely they all need replacing. Replacing them all at one time will save you time and money. You may as well do it while you’re “in there”, so while you have it apart, replace all that you can. Many of our subframe and differential bushings can be purchased at a discount with a parts combo with other BMW performance and racing parts from Condor Speed Shop, so if you are doing a lot of work on your rear suspension system, it makes financial sense to go with a combo.  

TIME FOR NEW FRONT CONTROL AND REAR TRAILING ARM BUSHINGS

If your E36 or E46 is experiencing any of these symptoms, check your rear trailing arm bushings and see if they are wearing and starting to fail or have whipped out completely. If they have, it is time to replace them. There are several options currently available. Factory rubber bushings are the most comfortable choice, but they will not hold up on track, and the rubber portion will eventually fail again. Performance-minded drivers might prefer to install our Delrin RTAB Limiters and run them in conjunction with the factory bushings which we also sell as a combo here. They will keep the rear trailing arms firmly in place without any additional harshness. The best choice for anyone who plans on using their E36 or E46 on the street and the track is to replace your old bushings with new RTABs made from ultra-high-molecular-weight polyethylene (UHMW). The material allows for the bushings to last longer than other urethane and rubber options, and they will provide a better experience for performance-minded drivers.  They feature black oxide plated steel plates which help prevent lateral movement between the bushing material and cage that contains the rear trailing arm. If you want to go all out, you’ll want to replace your rear trailing arm bushings with our monoball version. They are the best E36 & E46 rear trailing arm monoball bearings on the market. While at home on the street, this bearing is designed for track duty.

HOW TO CHECK FRONT CONTROL ARM BUSHINGS

Inspecting front control arm bushings involves visually checking for cracks, excessive wear, or deterioration in the rubber. A physical inspection for excessive play or movement in the control arm can also indicate worn bushings. Similarly, rear trailing arm bushings should be inspected for similar signs of wear or damage. A professional inspection may be required to accurately diagnose the condition of these bushings due to their critical role in the suspension system. Here is a great video we put together on how to install E30 rear trailing arm bushings:

SYMPTOMS OF CATCHING THE RACING BUG

Getting the urge to hit the track is the best possible reason to replace your old and worn stock bushings. Whether you are headed to your local autocross, drift event, or prepping a car for an endurance race, you will want to upgrade your rear trailing and front control arm bushings. We have various options, and our best all-around bushings are the UHMW versions. These UHMW bushings will aid in a suspension’s stiffness by having almost zero deflection, but also the ability to absorb some vibration, making them a must-have for a track car cornering at higher speeds. The best bushings available for BMW motorsport applications can be found at Condor Speed Shop and are a must-have if you plan on any on-track driving. The tighter feel and better car control provided by upgraded rear trailing and front control arm bushings will give you a competitive edge on the track and the street. 

FRONT CONTROL ARM AND REAR TRAILING ARM BUSHINGS FROM CONDOR SPEED SHOP

Acknowledging the wear signs of both front control arm and rear trailing arm bushings, and their timely replacement, is vital for the safety, performance, and comfort of your track-prepped BMW. Condor Speed Shop's exceptional lineup of bushings offers the quality, resilience, and performance demanded by racing and drifting. We offer rear trailing arm bushings for a wide array of BMW chassis, ensuring an ideal mix of comfort and performance. With the versatility of our UHMW bushings, your BMW will be well-equipped to handle city streets, improve ride quality, and maintain precise control on track. Enhance your BMW’s suspension system with Condor's high-quality aftermarket bushings and rediscover the joy of a BMW that feels brand new.