To start off this T4R no longer lives in a state with salty roads, but it does live in the beautiful Pacific Northwest were it rains 9 months out of the year. The pictures pretty much speaks for itself of what needs to be done, but I'm afraid of sanding or wire brushing off the rust because of the possibility it will start leaking. Should I leave it alone and hope it never leaks and if it does I can go from there on fixing the issue (Welding,JB Weld, getting another rear axle, etc). Or man up and clean that Wisconsin salt damage off!

I wasn't so concerned on getting this rust cleaned up and put some Rustoleum Rust Reformer till I had my front brakes, rotors and calipers changed at Les Schwab (which btw only cost $500 with slotted rotors) and they looked at the rear brakes and told me the right rear wheel axle seal is starting to leak . Now I would be alright with getting this repaired, but this rear axle is so effing rusted and I don't want to put $800 in getting seals, bearings and new brakes on the axle if the pumpkin ends up rusting away and leaking then I wasted all that money if I can't fix the leak.

Overall this rig doesn't have to much rust on the frame. There's no rotting or serious rust going on in the spots thats know for failure, besides the diff... It's a 1999 4x4 Limited with the factory rear locker and only has 82,000 miles.

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I would wire wheel it, clean it up real good and re-coat it once all the rust is removed.

Look, the damage is done. Leaving it will only allow it to get worse. And honestly, it doesn't look that bad. My rear diff looked that bad, maybe worse when I got it. I cleaned it up real good and hit it with several coats of rust reformer. It hasn't leaked at all in the couple years I've had my rig.

When you are done, clean up the rest of the truck (frame etc) and do the same. Use a product like LPS 3 or fluid film to prevent further rust.

If it does leak, it's not the end of the world to have it repaired (new cover welded on).

If you have a shop do your axle seals/bearings, read up on the new seal design and make sure the shop knows how to do it right. That axle housing has lots of life left in it, just needs some love....

If you’re super duper concerned have someone cut off the old one and have them weld this in. https://www.barnes4wd.com/Toyota-Pic...ver_p_228.html

I have one waiting to go on this winter as one of my winter projects

Doesn't look too bad but that cover has weird metallurgy, it could go deeper than you think. I'd go to Harbor Freight and get their $20 sand blaster and blast it off. You can't wire wheel that rust off, it just doesn't come off any other way. Then paint properly with primer and regular paint. I wouldn't use rust paint over it because it might just keep rusting underneath.

And also do the axle seals / bearings.

This would work if all else fails.

I was wondering if the rustoleum rust reformer could make things worse. My buddy told me to do the same thing and just use a primer. Sand blasting seems a bit extreme for this and could see blasting a hole right through it.

Don't dick with it IMO. Spray some fluid film and forget about it. Mine looks way worse, and I know if I start poking at it then I'm going to ruin my weekend.

Just did this on my Sequoia and it was way worse, no leaking any more. It slowly leaked away A LOT of fluid one drip at a time, which is bad.

Needle gun, chip off, wire wheel, whatever....get all the loose layers off then de-grease. You will be surprised how much comes off.

Double up some latex gloves and JB Weld standard issue, one pack will do the bottom half of the diff on one side. Mix then apply with hands. You can sand and make smooth later if you want.

After it cures in a couple of days, paint or undercoat.

Mine looked worse and it didn't go through. With that wimpy sand blaster you'll have ample warning if you're going to go through. Will take about 15 minutes to blast off the pumpkin.

I don't want to tell you to do something that pokes a hole in it though, I'd feel guilty. But on my mom's 4runner I poked a hole through it with a screw driver while chipping off the rust chunks. I had to drain the diff then use JB Weld and it's still holding up.

I just wouldn't paint over it while there's still rust on it. If you're worried do as suggested above and clean off the paint and loose stuff and apply fluid film.

Here is what mine looked like. I didn't sand blast this one, I use my dremel. It took all day to dremel the rust off. It would take 15 minutes to blast it off. Unfortunately all that work was for nothing because I swapped rear ends because my pinion bearing was going bad and I wanted an elocker.

I’ll definitely ask the the shop before I have the seals done on what they will be using. They told me this is a common issue with the rear axle seals on the 4runners and Tacoma’s. Only concern they have is the rust (being they don’t see to much of it), but I’m going to spray some PB blast a few times on the hub bolts before I drop it off. Btw do you think $800 is a fair price for the right and left axle seals, bearings and new rear brakes with a 3 year parts and labor warranty?

I ended up having a pinhole leak just right of where the brake cable bracket attaches. I used a sanding flap wheel and used jb weld putty, painted it, and voila, its good as new... I gave up on a long term solution as my truck it rusting to pieces but this will keep it on the road until the body falls off.

you may not be able to combat it forever. I bought a spare axle with a locker, disassembled and had it blasted, inside burned out with diesel, and then coated.

I had this issue with my 2000. It leaked in several places. JB WELD held for a while but it eventually leaked again. That metal is pretty thin so don't use any violent like a needle stripper or grinder. Get the loose stuff off with a thick wire wheel or sand blaster and paint it with POR15 or equivalent.

Oh, your price for the axle seal repair is pretty good. I would make sure they use OEM parts. 3 year warranty is nice too. And replace the rear axle breather.

I’ve decided to just leave the rear diff plate alone. I know they say “rust never sleeps” but I only see it getting worse if it was getting more road salt put in its wound, which It won’t being I don’t live in a salt belt state anymore. I’ll probably spray some fluid film on it and call it good like T4R2014 said. I also notice it was sprayed with something that I can’t figure out. It has a rough sandy texture, like bed liner spray. I also found this spray on other areas of the frame know for serious rust like where the muffler is close to the frame and rust due to salty snow getting wiped up there and melting causing it to rust as what I’ve read on forms.

As for the rear axle seal I did not bring it to the place that quoted me $800, because I just didn’t trust them to do the job right and most likely wouldn’t of used OEM parts. I had a automotive company in Portland that specializes in Toyota’s and was way more familiar with doing the job. Also the breather vent was rusted shut, which probably cause the seal to leak.


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Fluid film or at the very least rub some motor oil on it after an oil change. That rust doesn't look bad