I once asked my dad, who was driving me to the store one day, “How come I can feel every single bump and crack in the road when we’re driving?” to which he replied, “Maybe you think you feel every bump, but what about the ones that you don’t feel?”
It comes on slow, but when it does, it’s not only annoying, it’s downright dangerous. Some automotive designs are more susceptible than others based on the geometry of the suspension arms. It’s something that we all suffer from at least once in our lives. And if we’re avid automotive enthusiasts, it’s something that we all must deal with, either by reaching into our pockets to have someone else replace, or getting on our backs and fixing it ourselves. That’s right. I’m talking about control arm bushings. All cars have ‘em. All cars need ‘em.
They’re a high wear item on our cars and for good reason. They control the suspension travel and buffer the rough road noise/bumps/potholes so that you don’t have to feel them while driving. Most rubber bushings, durometer 60A from our previous polyurethane bushings post, is very soft. This is great because it’s comfortable, but it’s loose, non-sporty, and wears out fast. Not to mention, you need expensive pullers and or other creative tools to press it out.
What are the symptoms of bad Control Arm Bushings, particularly the front? The symptoms vary quite a bit, but the same general theory is the same. Steering wheel wobble at specific speeds is the most common. But bad control arm bushings can sometimes mask itself through warped rotors. Oftentimes when you brake at a specific highway speed, regardless of steering, the wheel shakes. This is due to bad ball joints on the control arm bushings. There are 2 ball joints on the E30 Front Control Arms. From Real OEM, see below:
As you can see there is no “upper” and “lower” control arm. There is just the single, triangular control arm, and it’s below.
Unfortunately, the ball joints are not repairable. However, it typically takes much longer for the ball joints to wear out compared to the rubber control arm bushing itself. So for most shadytree mechanics, the control arm is to be thrown out in the even that the ball joint itself develops play.
You can test for ball joint wear by taking a long pry bar and inserting it in between the control arm and the subframe. This allows you to see at a glance if the control arm ball joint moves, you have play and need to replace the ball joints, aka the entire control arm.
Another symptom of bad front control arm bushings is the fact that everytime you go over a speedbump, onramp/driveway, large crack, or quickly brake the car and hear a clunk, it’s much more likely that the rear control arm bushing, commonly referred to as the "CAB" is worn. If you look at the diagram above, you’ll see that the control arm is a stud going through a rubber control arm bushing. This membrane tends to wear out, and quickly if you drive aggressively.
You can replace these and fix any clunking you’re experiencing relatively easy. Here are the rough steps for replacement. Please note that we highly recommend you have these installed by a professional and if you decide to install any product by yourself that you are proceeding at your own risk:
- Remove the 2 M10 bolts that hold the “eyelet” to the frame. Use a 17mm boxwrench and NOT an open ended wrench. You need the leverage to remove. They eyelets contain concentric studs that fit very nicely onto the frame member of the E30. Unscrew them, stick a pry bar in, and pry it loose. Oftentimes, you’ll relieve some stress once you remove it.
- If the old bushing is bad, it will simply pull right off. But you’ll need to remove the bushing from the eyelet, so that you can reuse the eyelet. For this you can cut the inner diameter bushing from the eyelet twice, making 2 halves. Break through that wall and it will fall right out. Best way to do this is put it in a vice and use a sawzall to cut. See the figure below.
- Now you can replace the bushing. This is where it gets easy, and rewarding. I recommend Garagistic’s polyurethane bushings, 80A. Soft, but great for occasional track use. Perfect for street, and lasts for a ton of enjoyable spirited driving miles!
- Simply take the bushing and push it right in. The fit will be very tight and you will need to use a rubber hammer to get it 100% in as the friction increases during installation, but it will fit, and perfectly at that.
- Then, Installation of the eyelet is the reverse of removal. Torque the 17mm bolts (M10-1.5) to 14ft-lb.
Best of all, they come with a lifetime warranty!
For those looking for a sportier ride and more aggressive stance, you can always obtain offset control arm bushings. This allows you to have more caster, more camber, more traction.
When you go to place an order for Garagistic Control Arm Bushings, simply check whether you want the centered version (more factory feel) or offset (more aggressive for occasional track use), and whether you want 80A (more aggressive than factory) or 95A (harder and more connected feel) or even delrin (much harder and more aggressive exclusively for track use).
Thanks for reading and have a safe and happy modding experience with Garagistic!