Axle Painting

Here's where we stand with the axle restoration, with things greatly improved:  

I've spent a lot of time mechanically stripping the axle casings. It is difficult work: there are many nooks and crannies. There are lots of places where you can't get power tools like a wire wheel on a grinder. There are casting flaws to work around. These are simple castings, after all. Making it a little more challenging is the fact that everything is quite heavy! 

No matter, though. Persevere and you will end up with a piece of metal that looks as if it's finally ready to accept some paint. Clean of loose paint, clean of patches of greasy dirt (like you can see above) and free, mostly, of contaminating oil. 

Spoiler alert: It isn't, however. Not by a long shot. 

What you will need to do, and do many times over, is degrease and wipe down your part that you'd like to paint. I used three degreasing products on my axle casings. The first stage, during the early part of the stripping process, I used a product called Engine Gunk. It's reasonably inexpensive, fairly strong, does a decent job, and is available at your local Lordco or other fine automotive retailer. 

I then used a scotchbrite pad, a collection of wire brushes, shop towels, and various wire wheels to get the axle to the state you see above. I even stuck a bore cleaning brush for a .22 rifle on the end of my drill to clean out the threads for the rear cover plate. I figured it would be a good solution to cleaning out threads. It... sort of worked, but mostly just gunked up what was otherwise a very functional bore brush and turned it into something that looked like a greasy corn dog with a few brass wires sticking out of it. :/ I'm sure there's a better tool for this task, so maybe keep looking for a better solution and don't trash a bore brush. 

The next degreasing solution I used was the POR-15 degreaser. It's a concentrated product you mix 4:1 with warm water. I just leave mine in a trigger spray bottle. The directions suggest you give your parts a 15 minute soak in the degreaser, then rinse it all off with a hose. 

I did this exactly as specified, as you can see in the pic above.

Then I took some brake cleaner to a few stubborn spots where I suspected I had EP90 residue and wiped them down with a shop towel. It's hard to know if you're taking grease off or just surface rust -- it all sort of looks the same before and after you do this -- but I still figured it was important to make sure I hadn't left anything on the surface of the metal that would ruin my paint job. 

Finally, I applied the POR-15 Metal Prep liquid to the axle casing. I think it's just acid; what kind, I don't know. Wear gloves though, and maybe some eye pro, when you do this. 

At the same time, I also stripped off all the bolts and attachments from the axles, including the rear cover plate: 

I put everything in my small 10L ultrasonic cleaner to blast off as much gunk as I could. I manually cleaned each of the bolts and scrubbed the brackets. It's obvious that my diff cover plate on the salisbury will need some more work, though: 

There's not much hope that that will hold in any oil. I can probably sand it down though, it mostly just looks like surface rust. Will have to see if I can deal with any pitting and hopefully end up with a nice, clean surface to give the gasket a good chance for success. I mean, I know that Land Rovers leak oil. It's my hope that with some modern chemical wizardry and some care and attention, this one won't. Much. 

I'm also prepping the 4.7 Rover diff / axle combo for paint at the same time... and while I'm at it, my rear propshaft, too. 

So with all of that effort spent scraping, cleaning, and degreasing you'd think I would end up with a great finish... right?

Maybe painting is just not my forte. 

It doesn't look... bad, per se; but when you paint with POR-15 using a brush you inevitably get runs, drips, and thin spots, and it just doesn't look super finished. And no matter what you do, there will always be places you missed degreasing and the paint just won't stick at all. 

Oh well. It's axles and under-body components. As long as the coating sticks and holds up to my usual level of maintenance indifference, it'll be fine. 

And oh yeah, one more pro tip? Don't use your nice brush to apply POR-15. Use the cheapest piece of crap you have lying around. You can't thin POR-15 using normal thinners so if you use your nice brush, like me, you'll just end up throwing it out because it will harden into an impenetrable mass overnight while you leave it in a cup of regular hardware store paint thinner. 

You CAN thin the POR-15 Top Coat paint using normal thinners, however, and in retrospect that's probably a better place to use your nice brush, anyway...