rear end restoration

[Francais D.]

i just removed my differential to be taken apart and rebuilt, was working fine just ugly. I am curious on how to finish the case once cleaned. For example are these painted a cast color? I also have half shafts, shut rods and spring to do. Any help on either of these items would be greatly appreciated One note i did try to clean half shafts and shut rods years ago , i tried to leave natural using a clear coating from Eastwood only to have them rust and look terrible

[Domenic T.]

Re: rear end restoration

Francis,
There is a cast iron paint. It's better than Rust.
I think I bought mine at the local auto parts.

Dom

[Joe L.]

Re: rear end restoration

i just removed my differential to be taken apart and rebuilt, was working fine just ugly. I am curious on how to finish the case once cleaned. For example are these painted a cast color? I also have half shafts, shut rods and spring to do. Any help on either of these items would be greatly appreciated One note i did try to clean half shafts and shut rods years ago , i tried to leave natural using a clear coating from Eastwood only to have them rust and look terrible

Francais------


I've used VHT high temperature cast blast and found it very satisfactory. However, if judging is in your future, this will be detectable and result in point loss. In my opinion, though, it's the best overall solution.

If you are more interested in correctness, the best solution might be to have the unit media blasted and coated with a very light coat of high temperature polyurethane satin clear.

[Arland D.]

Re: rear end restoration

Agree with Joe - I have used cast blast 1200 on exhaust manifolds for many years and it results in a very nice, long lasting finish.

[Domenic T.]

Re: rear end restoration

Me too.

Dom

[Richard M.]

Re: rear end restoration

I used cast blast gray on this 66 differential, and many others.

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[Philip A.]

Re: rear end restoration

so are the diffs painted from factory or left bare only to rust ?

[Gary B.]

Re: rear end restoration

Left bare from the factory. To quickly rust.

[Domenic T.]

Re: rear end restoration

Gary,
Your right, that's why I painted mine! When I replaced engine blocks at Chevy they were bare cast. I checked out paint and lead to me getting fired. Also cleaned parts, and was told that we were not p[aid to clean or paint. I then told them to shove it!! Can you imagine having a new car with a rusting block?

Dom

[Tom E.]

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[Domenic T.]

Re: rear end restoration

I used cast blast gray on this 66 differential, and many others.

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Richard, beautiful job!!

Dom

[Domenic T.]

Re: rear end restoration

I hate rust.....

Dom

[Francais D.]

Re: rear end restoration

yes thanks , see i tried this stuff from Eastwood on my half shafts and strut rods ,forget the name. It was expensive and i think i mixed two parts together. It was clear and looked good for a while , maybe a year then quickly fell apart. So now i am back to cleaning them which means new u joints again ,i kinda just want to do it one more time ,and make it last. The pics are great

[Thomas N.]

Re: rear end restoration

Some of the vendors when rebuilding your rear end, put them in a shot blast cabinet before rebuilding. Then they like to paint them. I've asked them to keep them raw, and I used to use satin clear coat on a lot of cast items, but now use the RPM (Rust Preventative Magic) on items that I want to preserve and keep the cast iron look. It is a waxy substance, that you heat the part up with a heat gun and apply with a brush into the cast iron pores. This is now my go to. It is a happy balance between raw and painted coatings. Not for exhaust manifolds.
As for the leaf spring, there is spray cans that vendors supply, or you can use a zinc coating type paint, or light gray primer. All three are quite similar after painting and assembly.
I'm sure others will chime in with their preferences.
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[Joe L.]

Re: rear end restoration

A few more points:

As I mentioned, I have found VHT high temperature ("1200 degree") to be the best. Of course, that kind of temperature resistance is not needed for this component. However, I have found that this paint produces a finish and coloration more like natural cast iron than the non high temperature cast blast.

Also, when a sand cast iron piece like the differential housing is media blasted or shot peened, a finish like natural cast iron "out of the sand mold" is not produced. Applying a light coat of urethane satin clear will temporarily preserve it but it will not be preserving a natural appearing finish. It will be preserving a finish modified by the blasting agent.

I have an NOS differential housing [not for sale]. It is packed in a cosmoline-like coating in the original GM box. I obtained it from GM many years ago (it was discontinued without supersession in November, 1992 so I've had it for at least 29 years). I suppose if I removed it from the box, cleaned off the preservative with solvent, and applied a very light coat of urethane satin clear, I would have a housing that would appear virtually identical to how it looked on the car when the car was new. The urethane would preserve it for a little while, at least. Am I ever going to do this? Not very likely, at all. So, it's all "theoretical".