HOWTO: Buy Used Coilovers

I went to install some used coilovers a while back on a car and then they showed up, they turned out to be almost completely useless. I wrote this up and posted it on j-body.org but feel it's good enough to be archived here permanently and likely applies to most cars in that the parts that can go bad are very similar across different designs.

The guy had Koni Yellows and had picked up a used RK Sport sleeve kit to put on them. He clearly wasn't looking for a cheap solution and normally there's nothing wrong with used suspension parts so everything should have gone well. RK Sport's sleeve kits are nearly identical in design to what Ground Control produces, and not just some cheap generic crap from eBay.

Not knowing what to look for though, it wasn't until they got to my place to the install, that it was discovered what garbage the parts were.

I've written this page so people in the future can find it in a search and get an idea of what to look for when picking up used coilovers.

Note that this guide is specific to the Ground Control or RK Sport style of sleeve kit, that use bolt-tightened collars. Use common sense when evaluating other types of kits as well. If you can't adjust them, don't buy them. These things can seize up and you don't want seized ones.

First off, make sure you have all the parts that are supposed to be included in the set. Generally, this means the following:

• A pair of rear sleeves.

• A pair of damper adapters for those rear sleeves. These are basically aluminum rings about half an inch thick that fits snug over the body of the rear dampers. The rear sleeves sit on these. They may be stuck up in the rear sleeves when you get them.

• A pair of rear springs.

• A pair of front sleeves.

• A large thick washer that the front sleeve will sit on.

• If you get the kit already on some struts, ensure that the front sleeves and the giant washer they're sitting on can be slid up on the strut body. The ones we were trying to remove were solidly corroded to the strut and after hammering away at them for nearly an hour, I managed to move them less than 2 mm.

• A pair of top hats for the front springs.

• A pair of brass washers about the diameter of the top of the top hat and about 2 mm thick.

• 4 machined washers the same size (these are bearing races and you need 2 on each top hat.

• A pair of thrust bearings. These look like the machined washers but with little rollers set into them.

• 4 adjustable spring perches. And this is a key point... make sure you can loosen the bolt on each perch and freely thread it in and out. If the bolts are stripped or cross threaded then the perches may be garbage. On the ones we were working on, several of the bolts were completely rounded out and impossible to turn. Looking at the perches, you could see that they'd been previously torched to attempt to remove them.

Remember... if you're adjusting your coilovers, you should never remove the bolt entirely from the spring perches and if ever you do by accident, be VERY careful to ensure you don't cross-thread it when putting it back in.

NEVER adjust your coilovers without cleaning them first. You don't want dirt getting ground into any of the threads. This includes the threads of the tightening bolts. Brake cleaner does a good job of cleaning things up.

Always make sure your allen key is properly seated in the bolts before turning them. Again, you want to ensure they're clean so they can seat properly. Shoot the brake cleaner right into the bolt head.

Never overtighten the bolts. Once you can't spin the perch by hand anymore, you really don't need more than another quarter-turn of the bolt to tighten it. Any more than a half-turn will probably start doing some damage. It's also a good idea to put some anti-seize on the adjustment bolt when you first install them.

w²