12-bolt differential cover, black color and texture?

[71CHEVYSHORTBED402]

This is a picture of my OE differential. I hit it twice with naval jelly. There's still some rust. I haven't used any sandpaper or a wire-brush yet, because I'm not certain of the correct surface. Unless ill-advised, I'll probably soak it in white vinegar overnight.

I hit it twice with aircraft paint remover, then some Jayco garbage. Whatever it is, the black doesn't budge. Could this be it's because a rust converter was used?

Also, the face of it is textured, and the one on my truck is the same. Is the texture original?

Funny, there appears to a dent or two in the center on this pic. I need to take a peak. Edit: Yep. I managed the edges, but I'll hire this out. Not that it's obvious. First time I noticed.

[jocko]

to be honest, the texture looks as though it were rusted enough to profile the metal. Black, although I can't really tell where it is, is possibly rust converter, but if all you've done won't clean it off, I wouldn't worry about it peeling under your paint. Just sand it well. I've not seen a diff cover with texture, but that does look a lot like stuff I've had that sat outside for years and rusted - and it still looked this way after I cleaned it. Having said that, the part is perfectly good, but it may not provide the show-smooth finish you seek, if you seek one. I'd clean it thoroughly (you have), sand it some to see if you can affect that texture, and then slap it with converter (spray) and prime and paint it. It will be fine. Or, a new or other replacement without the texture should be able to be had rather cheaply. If you want it smooth, that's probably what you'll need to do. But it will work fine as is.

[bpatrol]

perhaps its powder coated?
you can get a textured finish with powder coating and it is difficult to remove. just sand it smooth and you should be okay
god bless
bpatrol

[71CHEVYSHORTBED402]

I'm not sure what metal profiling is. If you look online, you'll see all of these OE's have texture. I haven't seen an NOS, which would probably explain a lot. Take a look: http://www.google.com/custom?domains...D%3A1%3B&hl=en

[71CHEVYSHORTBED402]

Originally Posted by bpatrol

perhaps its powder coated?
you can get a textured finish with powder coating and it is difficult to remove. just sand it smooth and you should be okay
god bless
bpatrol

Aircraft Remover removes powder coating easily.

[71CHEVYSHORTBED402]

Well, I got it down to metal. Heck with naval jelly, white vinegar is your friend.

This was a real beatch. I believe there was some type of rust converter, but it only effected the surface, as there was lots of rust. There are a few flaws on the flat surface, but I think it's better I not sand any further down. Got a little carried away with the wire wheel (black area, lower LH side). May smooth things out a bit with primer, while maintaining some texture on the face. Anyway, this is approx. what they look like new.

[vics stuff]

Your cover has been exposed to serious moisture over the years
Vic

[indymachinist]

That is rust pitting. I don't believe they look like that new.

It is still a perfectly useable part.

[71CHEVYSHORTBED402]

Originally Posted by indymachinist

That is rust pitting. I don't believe they look like that new.

It is still a perfectly useable part.

There is some pitting. I could be off the mark here, but am fairly certain the faces on these are textured, similar the differentials themselves. The original on my truck is the "same" and it's been garaged in a dry climate. Shame the edge on it was jacked up ......Literally. It's possible they had a tendency to pit regardless.

[71CHEVYSHORTBED402]

Anyone have an original 12-bolt cover? Smooth or textured? Incidentally, the outer edge around the face on these are smooth. Don't know why it wouldn't be "pitted" as well.

[Bigdav160]

I've bought a new cover from the dealer years ago. It was smooth and unpainted. I think the factory might have sprayed some type of undercoating. I've seen the same texture on mine.

[GASoline71]

Factory they are smooth. But road salt and water usually pit the hell out of them.

Gary

[indymachinist]

That texture is absolutely from rust pitting. That cover would have been smooth when new from the factory.

[RustyBucket]

O'reilly will sell you a Spectre chinese chrome one for $18. Scuff it up with wet or dry paper and spray it with Krylon 1613. don't tell anybody.
your rear end(cover) will be smooth as a baby's...

[leddzepp]

Originally Posted by RustyBucket

O'reilly will sell you a Spectre chinese chrome one for $18. Scuff it up with wet or dry paper and spray it with Krylon 1613. don't tell anybody.
your rear end(cover) will be smooth as a baby's...

I did this too. Remember to scuff the chrome mounting surface, and it won't leak.

[71CHEVYSHORTBED402]

Originally Posted by indymachinist

That texture is absolutely from rust pitting. That cover would have been smooth when new from the factory.

Pretty sure you said I've got lots of sanding to do. That or buy an aftermarket. CRaaaaaaaaaaP!

[young grasshoppa]

can you even buy plain black covers these days? I only see the chrome ones for sale...

[71CHEVYSHORTBED402]

Only one I see in the same shape is chrome.

You guys were dead-on about the pitting. Course you knew that. It was pretty bad.

I had dedicated too many hours already, so I dedicated more. I've never done "precise" metal work before, but I hammered out the dents, which were all small (lucky). Shaped it right. Sanded, sanded and sanded. Kind of cool making it like new again. At any rate, I got most of the pitting out and it's flat. A couple layers of epoxy, it will be smooth too.

Was it worth the 8 hours plus scrubbing and sanding? Before I hammered the dents out I thought no (did it out of frustration with pitting, figured what the heck). Besides, I learned something. Thanks for your help.