I plan on sandblasting the rear end today and I was woundering how much would I have to strip it down? Is it alright to do it without taking the whole axles and diff apart? also how would you cap the top part of the diff (where the plastic piece normally is or maybe i'm missing something for there but thats how it was when i got the car.)

also when powder coating that would I have to mask off with the tape?

Thanks

 

Your best bet is to use an extra one of those plastic plugs or maybe find a rubber grommet that fits into it. PM 64mgb, he should be able to help as I know he has done this previously on his 85. He used POR-15 instead of powdercoat though.

 

ya i saw his thread .. but he took the whole thing apart so even is sand did get inside it wouldn't of matter because he could just clean the inside out anyway

 

i dont know about rubber, as sandblasting requires baking. contact trochoid maybe? hes a sandblasting man.

 

Strip it down and gut the moving parts. Sand gets everywhere, I have a diff full of it, lol. To powdercoat, all coatings and rust must be removed. Diff needs to be as clean or cleaner than when it came out of the sand casting. You cannot powder coat with any grease or lube in the diff. It will burn off and contaminate the powder.

 

Yea, it's alomst impossible to keep sand from getting anywhere it wants toget. When I started doing mine I was going to leave the axles and center section in, but decided I wasn't going to be able to do the job right, and I was leary about sand getting in despite my precautions when sandblasting.

Good luck!

Rich

 

alright another question then ... if I take the diff apart, can i reuse everything? (as in bearing, and stuff? or will I have to buy some new parts?)

Also is anything on our differential cast iron? I was told that I wouldn't be able to powder coat anything thats cast iron? Is this true?

 

I replaced the outer bearings, just because I was there, but unless you suspect they are bad it isn't a necessity.

https://www.rx7club.com/1st-gen-archive-71/drivetrain-replacing-rear-wheel-bearings-557114/

I didn't even replace the outer seals, but that was because I didn't know how easy it was...I would recommend doing that. Otherwise, you should be able to reuse everything.

I think the center section might be cast iron.

Rich

 

poR-15 needs to be sold in a rattle can...

 

Cast iron and cast aluminum are problematic when coating due to porosity of the metal. After blasting they should be chemically stripped/washed to remove contamminants from the pores, then pre-baked to outgas the metal. Sometimes more than once for the entire process.

If the diff is good, remove it as an entire unt, do not touch the diff nut or flange. Replacing bearings is not overly expensive, seals should be replaced.

 

Why? It is self-leveling and comes out amazingly smooth. I wasn't trying to make mine look like it was sprayed, but it would be difficult to tell that it wasn't (you can tell, but you have to look very closely). It's not good on anything that will be exposed to sunlight, so most of the time it will be on things that aren't going to be looked at closely anyway.

Rich

 

alright thanks guys ... also what kind of gasket silicon do u use to put the diff together?