S2000 Anti-bumpsteer Rear Control Arm Installation

This is part of a series of articles describing some work I did on my Honda S2000 in Dec 2004. Since I did several things all at once, the pictures and descriptions may not be exactly what you would see and do if you were to do this job by itself. Use proper tools, safety techniques, parts, and judgement. These descriptions and pictures are (to the best of my ability) accurate representations of what I did, but they do not constitute a recommendation for what you should do. If you are in any doubt about your ability to do this work, have the work done by a professional.

What this is all about

I decided to install the Go-fast Lab's S2000 anti-bumpsteer rear control arm kit.

Special tools required

You need a tool to remove the control arm from the knuckle. Honda sells a tool to do this, but I used an aftermarket generic tool. Cost about $5.

Parts required

Go-fast Lab's S2000 anti-bumpsteer rear control arm kit. (Shown here in comparision with OEM rear control arm.)


The "car side" connection of the control arm is where the OEM rear toe adjustment is made. Take off the bronze-colored nut (17mm socket). I needed to use an air tool for this, even though the Helm manual calls for a 40 ft-lb torque spec. I guess the shop that did my alignment may have gone a bit too far in torquing it down. Leave the arm in place, hanging off the bolt.

Now take off the castle nut from the wheel end.

I used some small bent-nosed pliers to undo the key. Then I used a 17mm box wrench to get the nut off. A socket wrench wouldn't fit. (In these pictures I have removed the rear brake caliper and rotor. I don't know if that is actually required. I was doing other work.)

Then use the special tool to pop the rod off of the knuckle. Use as directed in the Helm manual.

Now that the wheel end of the rod is loose, remove the eccentric bolt from the car end. Rod will drop out.

Install the new control arm in the opposite order from removing the old one. But first, the new arm can be adjusted for length. I adjusted it to be approximately the same as the old arm. Then support the car end of the arm with the eccentric bolt. (Do not tighten this bolt yet.)

Insert the new control arm into the knuckle. The old arm had a 17mm castle nut. The new one has a 19mm nylon locknut. Also, you will need to use a 19mm wrench to hold the bottom of the new joint. (I used a socket on the bottom and a box wrench on the nut.) Helm manual calls for the old castle nut to be torqued to about 40 ft-lb. Since I couldn't get a torque wrench onto the nut, I went by feel, attempting to get somewhere around 40 ft-lb.

Now you tighten the nut on the car end. Be sure to reinstall the eccentric washer! Helm manual also calls for this one to be 40 ft-lb. You will need a new alignment done on the car.

Make sure to tighten the locknut on the control arm length adjustment. With the arm installed it's not going anywhere, but you don't want it just spinning around loose.

Your alignment tech should reset the length of the bar when the alignment is done, so it is not crucial how long you set it when you install it. As long as the car is still drivable to the alignment shop!

Thanks to:

Thanks to Dad for bringing his air compressor and an air wrench over to my house. Also thanks to Ray ("RT") for the tip about his "mad rabbit tool", which is his name for the control rod extractor tool pictured above.

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