fightman80

I wouldn't use a rubberized undercoating, or anything else of that nature. Personally, I'm a little cheap, I use recycled Motor Oil left over from my oil changes. I put a plastic sheet down on the garage floor, park the truck on it, spray everything, then let it drip dry. It smells, but after a week or two, the smell goes away and then the truck is done. After a couple of years, you can skip a year here and there. Like I said in my previous post, my truck is virtually rust free, the rust that is there, was there when I bought it. I'll try to post some pics of the undercarriage today.

DeathCougar

iTrader: (23)

Did you just say you let motor oil DRY?

Lumpy

If you heat it with a small torch, propane, it will dry much faster!

fightman80

I let it drip dry, meaning, waiting till it stops dripping.

fightman80

mt_goat

Wow, that sounds messy.

BTW could you edit your pics so that they aren't side by side but rather one on top of the other. Thanks

DeathCougar

iTrader: (23)

Looks like a rusty oily mess.

The oil doesn't really appear to be stopping the rust. At all.

DailyDrive

That's the problem with any rust proofing solution, have to start when there is no rust, and then keep it up relentlessly.

Oiling over rust will turn to rust chips that hold moisture, and don't fall off because the oil based gunk is holding them. In the cold, snowy and salty climates its best to keep the surfaces clean, so moisture dries off quickly.

fightman80

In my opinion it has stopped it from worsening. It's over 11 years old, spent all of it's days in a climate which sees salt and snow about 4 months a year, and it still has original paint, and as for the undercarriage, the E-Brake is still fully functional, and the trucks underbody (floor) is solid. Everyone has their opinion, and oil spraying isn't for everyone. If you can stand the mess, adn don't mind getting a little dirty, it's a cheap option.

brian2sun

How about a fresh coat of black Rustoleum before the winters? I'm lucky, There's usually lots of snow, but no salt where I live in CA. It seems that a fresh coat of paint would go a lot further than a nasty coat of old motor oil.

fightman80

Again, the oil is not for everyone. I thought of using rustoleum on my under carriage as well. But tried it on my trailer hitch every year, and it peels and continues to rust more and more. I don't put the oil where you can see it, just inside the body panels, and under the truck.

I'm not sure, so correct me if I'm wrong, but do any of the nay sayers live in areas where salt is used liberally?

Either way, I simply offered a solution that I have used, and found to be effective for me. Like I stated prior to posting the pics, I bought the truck from the original owner, and it already had some rust issues underneath. The oil seems to have stopped it. Another option is to get it professionally sprayed for about $100. Depending on the quality of the stuff, I've seen them charge anywhere from $60 to $115. Most of the pros use non toxic, non smelling, dripless undercoating, and the good ones will spray inside all of your body panels in order to stop the vehicle from rusting from the inside out.

I'm sure there are other options, I'm just giving my input.

fightman80

I don't know how....it's only my second time posting pics, and they turned out like that last time! lol!

brian2sun

You're right, we use chains/studded tires where I live (well, at least the 2WDs do) so I don't have to deal with salt - And I'll tell 'ya, it's nice. I was just thinking that a fresh coat of paint before every winter would probably go a long way to combat the rust - not that the oil doesn't work too. It's just nasty. But, either method is still a lot better than having to replace a rusted out diff housing/axle housing/whatever else.

Dianna

My dad has a 2002 4Runner with the same issue. This is unbelievable! I did a google search and can't believe how many other people have had to replace their rear differentials because they were rusted out. How can Toyota justify saving a buck worth of metal instead of needing to make thousands of dollars in repairs down the road. Toyota refuses to acknowledge that their is a problem. I have an 89 Toyota pickup that has been sitting in my parents field (needs repaired) that doesn't have ANY rust flaking off the dif, still has most of the original factory paint. The only think I have ever driven are Toyota's and I currently have 5 of them. Getting ready to jump ship

quicksilvr

I'm currently using a product called Fluid Film to spray down everything under my truck. The rust was already pretty bad (see my panhard bar post). And so far I like what it's doing. I first sprayed the Fluid Film a month ago on the frame rails, the orange rust has turned to a black, wet looking surface. No buildup of crap, just seems to have killed the rust.

I'm sure the key to making it work long term will be to do it every year, but hey it's worth it if it saves the truck. I'll take some pictures this evening.

vital22re

iTrader: (2)

i know this is old.. but... you purposly spray oil everywhere.. okay. What happens when it rains? Your oil coating gets "wet" again and you're leaving oil everywhere. Not exactly the best idea in my opinion bro. Sure as hell wouldn't let you park at my house.

I would like to see the fluid film pictures though.

pwd

Ya, the fluid film is my favorite so far. I just need to to clean up my frame in some spots and spray some paint. Even without the paint/grinding, the fluid film does a pretty damn good job; you just have to keep the trouble areas coated, which is done easily enough since you can buy it in spray cans. I've got a spray gun and a large can of fluid film, and I will undercoat my trucks every year before winter now.

@fightman80 - I'm in the same area, so I know the salt/winter conditions and I will say your 4Runner does look pretty good so the oil must be doing something. Its the POs, if you don't undercoat your vehicle here, I wouldn't expect anything to last over 10 years. I would love to see what my Toys would look like if they've been undercoated (properly) every year. On a side note, I need to replace all of my rear brakes and backing plates because of the rust (thanks for taking care of the truck PO....NOT).

coonhound130

My 99 4Runner with only 135,000 miles has had the rearend rust completely through . I had to make a band-aide from sheet metal and weld over the hole .

j4eric

Just got back from the dealer and my rear diff is rotted thru.....2500.00 to replace....I am a very proud owner of my 99 4runner because it has not given me any major problems until today.....I have been watching the rust every year and ask the dealer if this was an issue....every year they said no....they said it was very thick metal and the rusting will not eat thru it......well....it did.......it's an 11 year old car and I do expect rusting....specially here in Massachusetts....but.....rusting thru to a point of rotting to a major component does not sit well with me......I expect rusting on the body work and under carriage but not to the differential to rot thru......something is not right.....the whole car is basically ok.....I am the first owner and it is garaged all it's life......serviced thru 2 Toyota deAlerships all its life.....I changed dealerships because I moved to a different town.....called Toyota HQ today, hoping they would offer even a discount on the part, basically I got the standard BS that you get from companies who would not want to deal with it.....they are legally out of it due to the age and mileage. 182k.......but my point is.....rear differentials should never rot thru....I will go to the dealer again tomorrow and talk some more.....I want a discount on the part.....I will pay for the labor...that's all I am after.....if they don't, Then I sadly say they lost a loyal customer in me and my entire family....I know they don't care if they lost me, but I surely feel bad about it....I am a Toyota loyalist....and I don't take that lightly......will post the outcome.

gornish_hick

had this problem about 2 months ago, and with a little picking I found a pin hole about half way down it, just packed it full of seal all for now and seems to be doing the job for a temporary fix. Gonna get it tacked and it should be fine. rust is my killer, gotta love the salt! other than my diff rotting away my rockers both sides are soggier than a rotten banana and flaking away. vut i guess thats the price we pay for living in the north!