Differential Case

[Scrrem]

Just pulled my differential/batwing for some gear upgrades. The case is stained from grease and road grime. Wire brushing doesn't seed to do much. Is there an aluminum cleaner out there that will help bring back the finish?
Scrrem

[secondchance]

Just pulled my differential/batwing for some gear upgrades. The case is stained from grease and road grime. Wire brushing doesn't seed to do much. Is there an aluminum cleaner out there that will help bring back the finish?
Scrrem

I have Auto Magic wheel cleaner that did wonders to my calipers. However, it is extremely corrosive and I don't know whether it would be wise to use on a differential case.
Did you try Simple Green? Another option I can think of is to clean it real good and spray it with aluminum finish paint spray. I think Mid America sells spray paint for magnesium finish valve covers for L98.

[Scrrem]

I have Auto Magic wheel cleaner that did wonders to my calipers. However, it is extremely corrosive and I don't know whether it would be wise to use on a differential case.
Did you try Simple Green? Another option I can think of is to clean it real good and spray it with aluminum finish paint spray. I think Mid America sells spray paint for magnesium finish valve covers for L98.

Yeah, I don't know if I want to go too aggressive, I'll try Simple Green but 20 years of staining, I may be down to your painting suggestion.

Rich

[flyin ryan]

Sodium Hydroxide. Closest thing to it that they will sell to the public would be '409'. I buy the base chemical by the drum.

[RICHARD TILL]

I`ve used muratic acid to clean parts before but i think i`ll try the sodium hydroxide the next time. Work with it every day and never thought about it. We use about 500 gallons every other day in a vessel regeneration process. The vessel is used for boiler feedwater purification. They`ll never miss a couple gallons.

[Aurora40]

What gears are you going with?

Also, have you tried anything like brake cleaner or engine degreaser? I'd think they aren't damaging to aluminum.

[Jim Nolan]

What has worked for me is once you get the crud off buff it with 0000 steel wool. It also works real well on aluminum parts under the hood and front suspension.

[Scrrem]

What gears are you going with?

Also, have you tried anything like brake cleaner or engine degreaser? I'd think they aren't damaging to aluminum.

4.10. Hope to get my 1/4 time down a bit for BG next year :)

I tried engine degreaser, it gets the crude off, but doesn't bring back the case color at all. Jagdpanzer is selling me the gears and installing for me, he may have some ideas on cleaning.

Rich

[flyin ryan]

I`ve used muratic acid to clean parts before but i think i`ll try the sodium hydroxide the next time. Work with it every day and never thought about it. We use about 500 gallons every other day in a vessel regeneration process. The vessel is used for boiler feedwater purification. They`ll never miss a couple gallons.I should point out that the Sodium Hydroxide I'm talking about is primarily a de-greaser, but does/can work good on aluminum finishes as well, when used correctly. The acid I use is Sulfuric Hydroflouric, it dosen't do anything for grease but on aluminum it will actually tear a microscopic layer of aluminum off. It's the stuff that some say turns aluminum white, while it does/can turn aluminum white-ish, it's not because it stained the aluminum, it is in fact because it took off the outer surface layer, what's left is the core/base aluminum. Looking back....not sure what all this has to do with diff's, LOL!

[secondchance]

I should point out that the Sodium Hydroxide I'm talking about is primarily a de-greaser, but does/can work good on aluminum finishes as well, when used correctly. The acid I use is Sulfuric Hydroflouric, it dosen't do anything for grease but on aluminum it will actually tear a microscopic layer of aluminum off. It's the stuff that some say turns aluminum white, while it does/can turn aluminum white-ish, it's not because it stained the aluminum, it is in fact because it took off the outer surface layer, what's left is the core/base aluminum. Looking back....not sure what all this has to do with diff's, LOL!

Checking the wheel cleaner I had used, it says "Hydroflouric acid". When sprayed on it foamed and ate up all brake dust off the real nasty build up inside face of the wheels. I was cautioned to wear rubber gloves and not to breath the fume. And yes, it turned my calipers sort of white.
This stuff was so aggressive I don't knoe if I would use it on the differential case. Next time, I plan on using it only on the inside of wheels and do so with the wheels dismounted.

[HAWAIIZR-1]

What has worked for me is once you get the crud off buff it with 0000 steel wool. It also works real well on aluminum parts under the hood and front suspension. :thumbsup: I agree, I have done the same areas as well as the heads and block too; works great.

[Scrrem]

Well, you guys are the bomb!!! Went to the store down the street, didn't have any Simple Green, but did have something call Purple Power, some industrial, bio-degradable degreaser. Scubbed with a wiire brush and wiped clean. Then buffed with some 0000 steel wool, here are the initial results. Not too bad, a couple more nights of scrubbing and I should have it done. Thanks all!!!
Rich

[secondchance]

Scrub away!!!:cheers:

[QB93Z]

It sure looks a lot better Rich.

Jim

[HAWAIIZR-1]

Hey Rich,

I might be too late, but I am slower than you and trying to juggle multiple projects with my build. I wanted to make the tired old diff and all the other components look better since I was doing a rebuild. I'm not NCRS and at the point of no return so what I did was fine wirebrush and still looks a little corroded and aged.

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC01712.jpg
What I ended up doing to do the batwing and will do the case is cleaned it with POR-15 marine clean/rinse, then metal ready/rinse. The other pieces in the tunnel (shields) area are all being done too.

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC01715.jpg

Then I applied 2 coats of POR-15 Stirling Silver then poly bushings. I love POR-15 and have been using it since I was in high school on my 68 Z/28 Camaro (boy I wish I still had that car.....even over my ZR-1). It came out pretty nice and it actually the same color as the aluminum when painting it on (used foam brush and fine paint brush for the detail areas). It took me a few days between the drying and tedious painting, but I'm really please with it.

I don't have my case right now as a friend is taking to his shop to remove the clips so we can rebuilt the posi before getting the 4:10s put in by a local shop. When I get it back I will do the same but the yokes will be POR-15 black. I'll post pics when I get that done and the whole deal together.

[Jeffvette]

Looks great Craig!

[HAWAIIZR-1]

Thanks Jeff, now if I can get it to run as good at it looks........:confused:

I think it could be blasted, but I would want to use something more gentle since mine was already a little corroded. That is why I figured I would protect and seal it since I'm way off original already.

[Hammer]

Boy that looks great. I'll keep the POR 15 iin mind.

[HAWAIIZR-1]

Boy that looks great. I'll keep the POR 15 iin mind.

Thanks John. I have always only used it on rusty steel (when restoring my 68 Z/28 and 49 Chevy Custom Rod) and never thought about it on aluminum. After consulting with tech at POR-15 and all the searches on the internet, I came across these guys in Australia and started consulting with them about the motorcycle engine (click on the pics to see how nice it came out) to make my decision.

http://www.ppc.au.com/feedback1.htm

Take care,

[Scrrem]

Wow Craig....looks awsome!!! Can't wait to see the case. In hind sight, I wish I had hit mine with some paint too, but it came out OK.
Rich

[HAWAIIZR-1]

Wow Craig....looks awsome!!! Can't wait to see the case. In hind sight, I wish I had hit mine with some paint too, but it came out OK.
Rich

Thanks Rich. I'm sure you did the right thing by keeping it original looking and yours came out nice from your pics. We'll see how this POR-15 holds up in the long run. :cheers:

[Scrrem]

I am assuming that your 90' case (is it a 90'?) does not have an oil drain plug. If not, did you install an oil drain plug since you have it all apart?

I am actually thinking of installing an oil drain plug (drill and tap) without taking it all apart :sign10:

My thinking is......any debris in the differential settled in the bottom of case is very hard to suck out by conventional means and any aluminum shavings (very little if I do it correctly) will all drain out including the other debris when I get the new threaded drain hole installed :happy1:

And...if I screw it up....that will be a great reason to go to 4.10s :sign10:

I used that tap kit when I did mine back in November. I was going to pull the axle to install 4.10's anyway, but I wanted to see if any shaving were left in the case. I taped the case and let the oil drain, then pulled the axle out and popped the cover. Couldn't find any shaving inside, so I would feel pretty confident using that kit.
Rich

[Dynomite]

I used that tap kit when I did mine back in November. I was going to pull the axle to install 4.10's anyway, but I wanted to see if any shaving were left in the case. I taped the case and let the oil drain, then pulled the axle out and popped the cover. Couldn't find any shaving inside, so I would feel pretty confident using that kit.
Rich

:cheers: Thanks for that information.....what size plug did you install?
Did you tap into the differential case just South of the lower center bolt on the flange?

That would be just below the ring gear I think? (Vet facing west)

[Scrrem]

:cheers: Thanks for that information.....what size plug did you install?
Did you tap into the differential case just South of the lower center bolt on the flange?

That would be just below the ring gear I think? (Vet facing west)

I am not sure of the tape size, bought the kit below from Corvette Central:
http://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50000050f~Z5Z5Z5AAUDT~ P66.95~~~~S2U50N0HXI13113113132a~Z5Z5Z5~Z5Z5Z50000 050F

The kit provides a template that puts the hole just left of the center bolt in the valley of the differential. See pic:

[Racinfan83]

I'm doing this drain plug. I got a new 1/8 x 27 npt tap off eBay for like $5. Had the 11/32 drill bit already. Got 2 1/8 plugs for $5 on eBay. So whole deal is waaay less then that kit....

[RussMcB]

One nice part of the kit is the tap has a stop welded to it. Not a necessity, but helpful. It also comes with a template to help determine the hole placement.

I plan to buy a bunch of extra 1/8-27 plugs then sell my kit (with spare plugs) to someone, who can use it then sell to the next person, etc.