Repairing rust on rear differential

[brillo_76]

I have one 4 runner done in rust oliem. Frame and underside. I won't know for several years if it's a decent paint product for this application as I still have that one on pieces.

Cast iron can be tricky, plus it really depends on the environment your rig lives in.

I see nothing wrong with using primer.

Did you look into the product called steel it?

Amazon.com


I am looking into that for a metal sealing product.


Also. If your paint is coming off with the masking tape. It is not adhered to the metal at all. Unless you are referring to the original paint..


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[phattyduck]

Toyota often leaves at least parts of cast iron parts uncoated... Here's the rear diff (6.7", baby!) from my Alltrac:

During a rebuild (bearings+crush sleeve) it was sandblasted and painted - but unless you live in a rusty (errr... salty) area, I'd just leave cast iron with simple surface rust alone.

-Charlie

 

[Speedy]

If it's simply coming up with tape, I'd go hit it with a pressure washer. That should get rid of most loose stuff. Can't be a cheesy electric one though. Probably need 3000 or so PSI.

 

[brillo_76]

Here is what a 2010 sienna dif looks like in PA. I will take a photo of the front were you can actually see the rust divits in the case from rusting the next time I have it on the car lift. I have to take it out to replace those axle seals. As you can see the passenger side is leaking.

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[Speedy]

That triggers my ocd and makes my teeth hurt.

 

[TheDurk]

Do NOT use wire wheels from HF. Unless you like surgery... Pic is me last year, went clear to the bone.
Spend the couple extra bucks on a decent brand. Jaz, Weiler, etc.

Yikes. I did my entire replacement frame for my frame swap with HF wire wheels. I mean every square inch of the thing from end to end and top and bottom. They did shed their share of loose needles and I certainly wore eye protection, but it never occurred to me that I could get hurt like that. Good to know.

My old diff has died. The same rust that killed the old frame did it in despite my attempts at rescue. I have a nice replacement used diff I am about to treat with POR-15. The frame has held up very nicely so I will give it a try on this diff. I guess I will look around for some new wire wheels. I still have a few left.

I tried like hell to find a locker but no joy.

 

[brillo_76]

Yikes. I did my entire replacement frame for my frame swap with HF wire wheels. I mean every square inch of the thing from end to end and top and bottom. They did shed their share of loose needles and I certainly wore eye protection, but it never occurred to me that I could get hurt like that. Good to know.

My old diff has died. The same rust that killed the old frame did it in despite my attempts at rescue. I have a nice replacement used diff I am about to treat with POR-15. The frame has held up very nicely so I will give it a try on this diff. I guess I will look around for some new wire wheels. I still have a few left.

I tried like hell to find a locker but no joy.

Instead of POR 15. Try the KBS seal. Less money, newer formulation. If the steel is clean, it should stick well... plus have uv protection in it...

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[brillo_76]

[MENTION=665220]Pyral[/MENTION] You making out on getting your diff all painted up? Paint and cleaned off and sticking good?

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[Pyral]

[MENTION=665220]Pyral[/MENTION] You making out on getting your diff all painted up? Paint and cleaned off and sticking good?

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I'm just doing the spots where the old paint coating has worn off, the whole underside of the car was painted before I owned it. All I'm doing is making sure that paint is intact.

So far the paint I've reapplied hasn't come off, but I can't say how well the products and methods I've used to repair this have worked, only time will tell.

From my experience with similar repairs you wont know you did a good job until a year has passed.

 

[brillo_76]

I'm just doing the spots where the old paint coating has worn off, the whole underside of the car was painted before I owned it. All I'm doing is making sure that paint is intact.

So far the paint I've reapplied hasn't come off, but I can't say how well the products and methods I've used to repair this have worked, only time will tell.

From my experience with similar repairs you wont know you did a good job until a year has passed.

Yes, mostly its 2 years... I painted several 4 runners underneath. Paint just gives us indication of what the status is anyhow.

Glad to hear its staying on..

 

[drey6]

Just pay someone a couple hundred to blast it. Drive her home and Kbs seal it. You’ll be good to go. If you use KBS. (Which I’m a fan of from personal use) mask off everything you don’t want it on, including you! Suit up, and be sure to wear a legit solvent rated respirator as it’s toxic to inhale.

Another easy viable option as others mentioned is to oil coat it annually or biannually. Fluid film is solid but many other products out there. It’ll last virtually forever with this method of rust protection.

In the wise words of my father when I was stressed about mine. “Don’t think too hard, it’s the underside of a truck after all.”
Doing something is the key, ignoring it is the problem

 

[brillo_76]

Just pay someone a couple hundred to blast it. Drive her home and Kbs seal it. You’ll be good to go. If you use KBS. (Which I’m a fan of from personal use) mask off everything you don’t want it on, including you! Suit up, and be sure to wear a legit solvent rated respirator as it’s toxic to inhale.

Another easy viable option as others mentioned is to oil coat it annually or biannually. Fluid film is solid but many other products out there. It’ll last virtually forever with this method of rust protection.

In the wise words of my father when I was stressed about mine. “Don’t think too hard, it’s the underside of a truck after all.”
Doing something is the key, ignoring it is the problem

I am sure the OP is well aware They can pay someone to sand blast it for him if he wants too. I would Image that from the previous posts the OP is more of a DIY and learn type of person. Which I wish the world had more of these days. Skills are always good things to have..

Yes. Sand blasting and using metal prep and cleaning are the only way to get kbs /Por 15 to stick to metal decently. If the metal was really rusty it kinda bleeds through as well. I have some Metal I did a few years ago and hanging in my garage. (Gas Tank Skid plate) with multiple coats of kbs seal.
You can see the rust oxide bleeding through before it stopped and sealed it off.. The Irony is that neither of those products will stick to brand new rust free steel either without sanding the service some.. Along with Some cases, they will bleed the rust oxide through..

 

[TheDurk]

Instead of POR 15. Try the KBS seal. Less money, newer formulation. If the steel is clean, it should stick well... plus have uv protection in it...

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Except I have more than enough POR-15 system left over from my frame job. Maybe next time.

 

[brillo_76]

Except I have more than enough POR-15 system left over from my frame job. Maybe next time.

Fair enough.


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