Blasting a diff??

[Cloggy Saint]

Just picked up a diff and it's as scummy as hell, rust, moss, the works. Is it safe to get it sand blasted or could that mess with the internals?

[Brianmoooore]

Electrolysis! Couple of days, and it'll be like new.

[maggspower]

I do a good bit of blasting, and I would say no to it unless you are stripping the diff right down. Grit will be blown past the seals and enter the casing. I use soda too, this will not harm anything but it won't get the rust off either, it will clean the cover up though.

If its real titanic spec, I have used a small hammer to get the rust off before a coat of paint. Once you have knocked the worst of the rust off you could use kurust or better still some of the bilt hamber products to treat the surface if you need it to super bufty standards.

[Cloggy Saint]

Ok, thanks, No idea where I could get the electrolysis done, so small hammer it is then.

[Brianmoooore]

Do the electrolysis yourself! All you need is a bit of scrap iron, a spoonful or two of washing soda, a non metallic container big enough to put the diff. in, and a DC electrical power supply. A 12 volt battery or a battery charger will do at a push.

[Speedtouch]

An alternative method is to dunk it in a bath of cheap vinegar or even coca-cola and leave it for a day or two. The mild acetic acid will remove most of the crud.

[Brianmoooore]

An alternative method is to dunk it in a bath of cheap vinegar or even coca-cola and leave it for a day or two. The mild acetic acid will remove most of the crud.

And probably the plating on the speedo. sensor pins as well. The beauty of electrolysis is that it uses no corrosive chemicals, and once rust is fully converted to iron, further electrolysis does no harm.

[jimbom30cab]

DO NOT blast as it WILL get media into the diff, i have seen this before and its a pain to get it all out.

[Brianmoooore]

DO NOT blast as it WILL get media into the diff, i have seen this before and its a pain to get it all out.

It definitely will. With electrolysis, as long as you leave the vent just above the water level and the seals are good, nothing should get into the diff, although an oil change afterwards is probably a good idea, just in case.

[DanThe]

Cola does p1ss all to rust, I left some rusty calipers in it for a month and they came out the same as they went in

[Royalratch]

Cake it in WD40 and leave overnight and you should be able to 'scrub' most of that stuff off with an good stiff brush.

[Cloggy Saint]

I might have a go at the electrolysis tank, it looks simple enough to set up.

[Nobby_N]

Leave it rusty and weld it up, job jobbed

[Kos]

Wire brush attachment to a drill should get rid of most of the flaky rust

[jimbom30cab]

That's exactly what i used Kos

[polsta]

you know what im going to say here FERTAN !! serious tho, use a wire brush etc to get rid of most/thickest, then paint it in fertan, leave a day or 2 , then paint it, would be an ok job

but the electrolysis sounds good idea, id like a go at that myelf

[Andyboy]

I've blasted lots of diffs without a problem. There are steel covers over the seals and whilst you will get a bit of it behind the metal dust covers on the pinion and output flanges, you can pop the side shafts out and clean it up, and blow any grit from the pinion shaft cover with compressed air. If the metal covers are there, it will not get into the diff!

[Brianmoooore]

Electrolysis is so easy, cheap, effective and effortless, that there's really no reason to consider any other method on anything that can be immersed in water.
The action is purely electrical - the soda is just there to make the water conductive, so doesn't get 'used up'. The only reason to renew the solution is because it turns bright orange with suspended rust particles, but these will settle out if the solution is left, and clean solution can be decanted off of the top.
The de rusting action mainly takes place on the face of the rusty item that is facing the anode, so for something like a diff., you need to use three anodes placed around it, all connected together, and to your power supply positive terminal.

[Cloggy Saint]

Will definitely give this a shot. I'm going to use a plasterer's tub as a tank, would it work if I used a piece of gauze that lines the entire tub as an anode? That way all the surface would get treated at the same time?

[capnmchl]

The greater the surface area of the anode, the more effective it will be. I can't imagine gauze will be that good.

[Brianmoooore]

The anodes will gradually be eaten away, so can't be too unsubstantial. I've heard of large tin cans being used with the top and bottom cut off though, leaving a steel tube. Gauze should work OK as long as its not plated.
The connection to the anode needs to be out of the liquid, but the cathode connection can be immersed.

[milescook]

Electrolysis is so easy, cheap, effective and effortless, that there's really no reason to consider any other method on anything that can be immersed in water.
The action is purely electrical - the soda is just there to make the water conductive, so doesn't get 'used up'. The only reason to renew the solution is because it turns bright orange with suspended rust particles, but these will settle out if the solution is left, and clean solution can be decanted off of the top.
The de rusting action mainly takes place on the face of the rusty item that is facing the anode, so for something like a diff., you need to use three anodes placed around it, all connected together, and to your power supply positive terminal.

Honestly this is one area where an easy solution actually works better than elbow grease! Let electricity do the work for you

[Cloggy Saint]

I've got all the necessary bits to do this, it's definitely ok to submerge a diff' in water??

[Brianmoooore]

I've got all the necessary bits to do this, it's definitely ok to submerge a diff' in water??

Keep the vent just above the water level, and if all three seals are good, no water should get in. Even if a small amount does, it'll come out with an oil change, and isn't going to hurt in there for a day or two.

[Speedtouch]

I wouldn't personally - surely, a going over with a wire brush is probably safer?

But, if Brianmoooore reckons it's OK, then I suppose it probably is. As he says above, as long as you give it a precautionary oil change afterwards, then it will be fine.

[initial_g]

Dont blast it mate I blasted and powdercoated one on a previous car (against advise not to) looked great but needed a full rebuild after.
Atach it with a wire wheel on a drill and hammerite it bud, take the rear cover of and get it blasted (£10)
Heres mine... not perfect but its no show car
Before



After

[Morat]

All I need now is a plastic bath big enough for my tailgate

[Cloggy Saint]

To be safe the blasting option is definitely out, and I'm a bit reluctant to put it in a tub of water too, despite Brian's assurances, but I'll build the electrolysis tank for other parts. Wire wheel and hammerite it is then.

[BATTS91]

If its not leaking oil then surely water wont get in . I will be trying this soon .