We’ve made plenty of posts about radius arms, but once again here’s one that defies all prior worn out pieces. This one is so badly worn that both the front and rear bushings are flopping all over the place, as you should be able to see in the video below.
Because of the design of the rear suspension on Bugeyes and Sprite Mark II’s with quarter-elliptical springs, the radius arm bushings are critical to locate the axle and stop it from clunking on acceleration and deceleration. Once those bushings tear, the rear axle is banging all over the place. This is a critical repair if you want your drivetrain to function properly.
There are rigid radius arms available that employ Heim joints in lieu of rubber bushings, but we don’t recommend those because we find that they make the rear suspension very jarring under load. While you’ll never have to deal with a failed radius arm bushing again with this setup, you lose a lot of the comfort that the original design provides for your rear end.
Take a look at your bushings by leaning into your rear wheel arches. You will be able to see if the front bushing is cracked and needing replacement.
Almost every car that comes through our workshop gets a set of brand new radius arms with new bushings installed, which we sell in our catalog. We also sell the radius arm bushings if you want to change them yourself with a press; in general, however, we recommend simply changing the entire radius arm, as the new ones come with new bushings ready installed as well as a nice paint job.
Keep in mind when installing new radius arms that you cannot tighten the fasteners for them with the car in the air. Tightening the radius arm bolts with the wheel off of the ground adds rotational torque to the rubber bushings, cracking them before you’ve even driven a mile and making them susceptible to early failure. Click the photos below for our radius arm-related parts offerings, or click here for our full catalog!
