Polyurethane Bushing Install

by Nic Huffman

Nearing the 100k-mile mark, I decided to replace all of my stock bushings with stiffer polyurethane bushings from SuperPro. This project really took a long time, as it became more of a suspension restoration than a bushing replacement. Below are some of the problems I ran into.

Despite a week’s worth of oiling, many of the bolts on my suspension were rusted in place. The worst one was the long bolt on the lower edge of the rear upright. I should have been oiling the bolt on either side of the exposed part in the middle. This was a major fight.

Removing the stock bushings is a real pain. I ended up using a sturdy 150mm c-clamp and a large vise that probably opened 200mm. This also took some creativity. All of the bushings are either 38 or 40mm in diameter, so you need to purchase a pipe coupling of approximately the same size to press the old bushings into. You also need something to press the old bushings out with. I used a stubby screwdriver with the blade inserted in the hole in the bushing to constrain things somewhat.

My suspension arms had begun to rust a little bit. I couldn’t help but fix it. I used a wire cup brush in an angle grinder to remove the rust and old paint. I removed surface oils with brake cleaner and gave the arms 2 coats of Rustoleum black primer. I’ll update this later if this didn’t work well.

I found all 6 ball joints on the front suspension slightly torn. To fix this, you have to pop the joints free. I used a hammer as directed in Keith Tanner’s excellent book, but this is a real bitch. I will buy a ball joint remover if I have to deal with this again. When you get the joints free, you can remove the old boots with a screwdriver. Wipe out all of the old grease. Now put a nail through the holes for the castle nut and check that there is some torsional resistance. If your upper ball joints are gone, you have to buy the whole upper arm at ~$200 each. The lower ball joint and the tie rod ends are both ~$60 each. Repack the joint with fresh grease. The new boots can be pressed on in a vise. I bought some plastic pipefittings at the hardware store whose inner diameter matched the diameter of the base of the boot to press the new boots with. Spray the outside of the boot with WD-40 before you press it on to lessen the chance of tearing.

Pressing the new bushings in by yourself is hard. I got my brother to crank the vise as I supported the control arm with one hand. I guided the bushing in with my other (greasy) hand. This is a nice time to use gloves. The purple ones I ganked from the lab are much stronger than the white ones from the parts store.

I made sketches of each alignment bolt’s position before I disassembled the suspension. On reassembly, I replaced the bolts where they had been. This gave me a fairly good alignment for the ride to the alignment shop. Some of my alignment bolts showed signs of twisting, so I replaced those with the new, stronger bolts. The new bolts supercede the old ones, so they should be what the guy at the parts counter gives you. They now have 2 grooves in the threaded area.

If you are into weight reduction, you can remove the brake shields. I used a Dremel with a cutting disk to cut most of the way through, then ripped the rest of the way through with pliers. The front brake shields (with bolts) are ~330g each.

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12 June, 2005