Rear Differential Pt. 2

October 20, 2020

Alright, well, let's start stripping the diff down, I suppose. What else am I gonna do?

A while ago I bought an 'inexpensive' 10L ultrasonic cleaner. I figured, I might be able to use it for both car parts and maybe also cleaning up some brass. Well, what with various political issues and pandemics and whatnot, I haven't used the thing a lot so far. But what the heck, let's see if we can clean up the diff.

I threw anything that wasn't carrying a bearing (pinion shaft and crownwheel assembly) in there with some hot water, degreaser, and Dawn. I have to say, it worked pretty good!

I had to flip the pinion housing around a couple of times to get it all cleaned up, but it degreased everything really well and removed a lot of the flaky paint that wasn't sticking very well. Not too shabby. You can see the remains of the red paint, above and below, and the general cleanliness of the piece. All I used was a wire brush and a flat blade screwdriver to clean out the machined surfaces.

The fasteners and 'bits' cleaned up fairly well, too. The ultrasonic doesn't seem to take out the really deep caked-on grease; you still need to agitate it off somehow, with a brush or something. But the bearing races and various bits and bobs came out pretty nicely and everything that was on there wiped right off. 

I'm glad I did this. There were a bunch of metal flakes contained in the parts and in the bottom of the ultrasonic. I'm glad that's loosened up and now out of the way. You can't see it really well, but the towel I used to dry the parts has a bunch of shiny flecks all over it. Glad that's out.

Sorry, I realize that was just a picture of a paper towel. Not very exciting.

Next step, I guess, is to do something with that unprotected metal. So, I bit the bullet and bought one of those 'starter' kits of POR-15. You know, the stuff that costs an arm and a leg and, if you get it on your arm or your leg, it never comes off? Yeah. That stuff. 

I don't know much about painting. The last time I tried it, the 'job' didn't turn out all that well. I've read a few things though and watched some videos on YouTube. So of course, I wonder, "How hard can it be?" 

First step, degreasing and etching. Easy enough. 

Turned out OK. Not that complicated, and the 'kit' makes it easy. They give you everything you need. 

I think it turned out OK. This picture was after my first coat. It goes on a little thin, which I thought was a bit weird at first. I suppose it's meant to flow really well. It did leave some high spots though, as you can see from the lip of the driving flange, above, and on the machined edges where the washers and nuts go.

I was concerned about the paint curing properly given the low temperatures we've been having, lately. As it turns out, I needn't have worried. I threw a space heater on but I don't think it did much. I wasn't prepared to leave the heat on in my garage all night.

If you haven't used por-15 before, get the starter kit and follow the directions. The paint can they give you is absolutely tiny, but it lasts pretty well. 

Oh, and pro tip? Make sure you put some plastic wrap between the lid and the can when you reseal it, otherwise (I'm told, by the internet) that it'll never come off again.

I made a bit of an error when I was reassembling the driving flange and the little 'gunk ring' that presses on. It's a tight fit, so I used my vise to support the work piece as I hammered on a block of wood to drive the ring onto the driving flange. Unfortunately, I did not pay attention to what I was doing closely enough, and I marred the surface of the driving flange with the jaws of the vise. :( 

I think that means I essentially have to throw this part out, because it's unlikely it'll ever make a good fit with the pinion oil seal. :( :(

Kids, learn from my mistakes, and get aluminum jaws for your vise.