OK, I just pulled the rear end off my datsun replica. (This is part of my rip-out-the-drivetrain-to-install-the-firewall™ build methodology.) Since I already have it off, I may as well try to clean it up and rattle can it.....The open sides on the engine bay sort of dictate a painted engine, and I may as well make the rest of it match.
As you can see, the rear end currently has a lovely patina of 70% rust, 30% grime.
How would you guys clean this up and prep it for painting?
Wire brush, mineral spirits, por 15.
Off topic but I had a diff cover rust through on a 97 truck I bought a couple of years ago, went to go to work one morning and found the driveway covered in gear lube. I've seen a car sit in the junkyard for fifteen years that never rusted like that.
Wire brush the crap out of it or I like those little 3m sanding disks for stripping crud of in a hurry. Clean it and clean it again with something strong rinse well, dry and paint.
pressure wash or degrease, wire brush to remove heaviest rust, brush on muriatic acid to remove rest of rust. repeat as necessary. it will flash in a hurry. paint or coat.
acid is one of my fav tools on steel or weld prep
Scrape the heavy stuff with a putty knife and a big wire brush then use an assortment of wire wheels and brushes on a drill followed by carefully wiping with wax and grease remover. Be sure to get into the corners and crevices well. Paint as desired.
Soda blast it? Maybe glass bead blast it as well?
On the torsion bar carrier for my 924, I used a wire brush in a drill and just went at it. Once I got it down to reasonably clean, I primed and painted it with Rustoleum rattle cans (satin black hides a lot of imperfections, heh).
Cleane as above and POR 15 or Rustoleum primer over a rust converter like phosphoric acid to neutralize the rust you didn't remove. Then paint with some impact resistant chassies paint.
OK, another question for those of you advocating POR15....is it true that normal paints/primers will not adhere to a POR15 surface? My intent was to paint the engine, tranny, drive shaft and rear end red. (Just because I though the red engine would look good)
Topcoat the por while it's tacky or add a primer coat while there's tack to the por - let it all set up and it will be fine. Otherwise paint has trouble sticking and you about have to use a grinder to rough up por after it sets up.
nicksta43 wrote:Off topic but I had a diff cover rust through on a 97 truck I bought a couple of years ago, went to go to work one morning and found the driveway covered in gear lube. I've seen a car sit in the junkyard for fifteen years that never rusted like that.
Had the same problem with my '94 Chevy K1500, except it was a pinhole leak.
OK....headed to the garage. We'll see how this goes. 
It cleans up OK
Now I need to pull the brake lines, leaf springs and wheels off so I can finish it
POR is designed to be painted over as it fades in direct sunlight, just prep correctly and advise the paint store what you are painting over
I like to paint suspension parts with Hammerite. Good stuff if you can find it. The rustoleum just chips right off.
