Nordz

So I purchased a 3.63 torsen from Europe and it arrived pretty rusty. Functionally its fine. However, I wondering if this is a future problem. The metal is flaking quite a bit. I am worried about rusted bolts. I want to take care of it sooner rather than later.
My question is should I....
1. Clean the **** out of it with a wire brush and a mild acid clean and paint with Por 15. Send it and expect that I will never have to deal with it again.
2. Remove the bolts (replace with new bolts and maybe a RX7 fc housing) as well as clean as option 1.
3. Sell it.
4. Stop being a ***** and send it.

Frofro97

I would take option Number 1, maybe replace the bolts because they will only get worse to undo if needed. you will probably blow it before you need to disassemble it though.

WigglingWaffles

Got a similar diff in similar condition.
I just chipped off the big flaky bits and wirebrushed it real good.
Ymmv but that was good 'nuff for me.

Replacing hardware (and seals!) would be good measure, but as long as the bolts arent completely caddywompus, reusing them wouldn't be the end of the world

Turbomack

My personal experience with rusted bolts that look like this is about 1 of every 4 will twist/break off and then the remover bit will break off inside the bolt. Wouldn’t touch them if diff is good or I were fully prepared to deal with broken bolts. If I really had to or wanted to take them out, I would soak in penetrating oil over and over for about a week, heat it with a torch, “ping” it with a hammer near each bolt with the hope that they come out without breaking.

I found a recipe that people have had success with getting out the 2-piece spark plugs from the mid-2000 Fords. It was a mixture of penetrating oil and carb cleaner. I will be attempting that over the holidays and using this brew but not yet tried it on rusty bolts. Good luck!

hks_kansei

I'd wire wheel it to remove the scale, also to let you see if there's any really deep pitting, or rust on any gasket surfaces (ie: axle seals)

remove the bolts, replace where needed.

then give the whole lot a good coat of paint


Plus, it's not a bad idea to crack open a new diff anyway to both visually confirm you have what you paid for, and to check for any tooth damage etc.

joe morreale

I got an engine from Europe that looked like that. Mine was just exterior scale. Just wire brush the hell out of it, soak bolts in blaster, then replace bolts. Paint any color you like.

Tran

The case on mine looked worse than that when I removed it from the car to get the OS Giken installed, but all the bolts undid OK with Plusgas spray (penetrant) and using an Impact gun with a direct 1/2" socket of the right size.

Something to point out on the Miata parts from the UK at least... Most cars are only being broken for parts because they actual shells are so rusty that they're not roadworthy.... So it can probably be assumed that the running gear has had a similarly harsh life from a corrosion aspect.

Frofro97

ATF and acetone is what I always heard worked well.

rleete

iTrader: (21)

ATF and acetone, mixed 50/50 is a miracle penetrating oil. It needs to be shaken up frequently, as it will separate. But, having tried everything on the market, I will say it is the equivalent of Kroil, at about a tenth the price.

+1 on the suggestion to remove the bolts now, while they are easy to get to. Replace if necessary, or just clean them up. Then throw some paint on the whole thing.

HarryB

Option 2; would cover axle seals and sandblast before taking it apart to replace bolts, but wire wheel would work. Oh and +1 on the acetone/ATF blend.

Nordz

Thanks for the responses guys.
I looked into sending it back. Fedex online quoted $600.
My bro-law offered to help sand blast it. I am leaning toward opening it, checking the gears, up replacing the bolts and painting up.
Will hopefully necro this thread with finished photos.
Hopefully you guys are smarter than me and get photos of stuff before they purchase from UK.
I have purchase a 6 speed, leather seats, and a square top from Uk all of which look great for the shipping. Despite this diff, Id probably will still be ordering again.

hks_kansei

Worth considering checking out Aussie retailers too.

We got most of the same options as the UK models (like the 3.6 diffs) but they're usually pretty clean since very few areas actually get snow (and therefore don't need the road salted)

Supe

X2, that's an inexpensive media blast, and exponentially quicker. It will also give you a prepped surface for paint.

Nordz

Got my 3.6 and 4.1 torsens back from brother in law the media blaster. He recommends KRYLON epoxy spray paint as he says "its the closest thing to powder coat in a can".
He said if I wasnt family he'd charge $80 a diff. So far, I feel really good about this result.

Erat

iTrader: (5)

Send it.

Parts up here in the rust belt are in far worse condition.

If it works, why open it? If you kill it, why open it? Change the fluid, knock the big stuff off and use it. It's fine.

Nordz

At this point I plan on just running the housings as they are.
I found a guy with 2 rx7 open Diffs; both FC.
Both for $150. I figured the'd be some nice back ups. The housing on the Left is an S4 and the right an S5. The S5 appears to be beefier.
When I was researching this I hadnt found any photos for comparisons. So I thought Id post some. Also note the reason you need an open diff is because the ring is 7"; while the LSD from the rx7 is an 8".
When I opened the S4 it had sparkly oil. I am assuming this means the diff was toast.