6/6/2004: Cleaning and Painting the Subframe and Suspension

I’ve been planning to build a new subframe assembly, complete with front suspension, and then swap it out in one step. I already had a complete rebuilt subframe from the parts car (#40912), which included numerous new parts. However, all the rubber in the bushings was badly cracked, and it was painted a weird blue color instead of the correct black.

As I disassembled the subframe, I found a number of problems with it which have needed fixing.

  • rust repair
  • rotten (though new) rubber
  • one of the upper control arm cross bars was overpainted on the area which is meant to rotate inside of the bushings, caused them to bind, and would have shredded the bushings.

After I got the control arms back from being blasted, I noticed that the threads where the trunnion bushings screw in were pretty much gone on two of the arms (one upper, one lower).

Fortunately I had another spare set of front suspension parts, (other than the ones which are on the car now). I found two replacements that were less worn and substituted those.

This gave me an excuse to learn how to get the bushings out of the old ones, with an air chisel. This is now my favorite tool of the day. BRAAAAAPP! Done. BRAAAAAPP! Done.

Unfortunately, since these arms were rusty, this meant sandblasting them on my own. Blasting in my little cabinet is really tedious, but it’s the best way to get this done quickly.

Once I finished that (it took a few days), I degreased and wire-brushed the spider trunnions and steering knuckles, as well as touching up the subframe.

Over the weekend, I finished up cleaning parts and painted them with the first coat of POR-15.

Underside Painted

This time I tried using a foam brush. It worked quite well, and tended to spatter on my skin less than bristle brushes had. I’ll put a second coat on everything tomorrow. Then i’ll flip the subframe and paint the other side.

After that, I’ll topcoat with a lower-gloss “chassis black” color, which will look more correct and protect the POR-15 from UV light exposure. The POR-15 does dry fairly smooth, but there are some signs of brushing and occasional bubbles. I’m going to experiment with sanding, then spraying the chassis black topcoat, which I hope will give a smoother finish on the flat sections of the frame.