By John Gunnell
For years we've been using a cabinet blaster loaded with aluminum oxide to restore the looks of coil springs on old cars and vintage sports cars that come to our shop. Then, a few days ago the owner of a body shop who does body work for us came in while we were blasting some Triumph TR-250 coil springs.
"You're media blasting coil springs?" he asked in a surprised tone. "Don't you know that you're not supposed to do that because the heat generated by the blasting process them takes the temper out of the spring steel."
Obviously, we didn't know that and we weren't even sure his information was correct, but it sure seemed like he had hit upon a good topic for a technical article. So, naturally, we hopped on the Internet and started trying to find out whether we had ruined our customer's springs (if we had, new TR250 coil springs are readily available from Moss Motors or Victoria British).
Here's how a typical old coil spring looks after the paint falls off and moisture and road grime get at the bare metal causing it to rust.
The coil spring is a part of the suspension system that is under load when compressed between the upper and lower wishbones and other suspension bits.
This coil spring and related parts gave been cleaned by wire brushing and could be finished with a "rust paint" if you're doing a "driver" type restoration.
Rubber seats like this one are used on top and bottom of a coil spring and can sometimes be cleaned up or replaced with new ones during a restoration.
Coil spring compressors like these can be used to compress a spring for removal. Be very careful. A loose spring can become a dangerous flying object.