Rust: A 4Runner's Worst Enemy

[RyanMcCarthy]

Over the years, my '99 Limited 4WD has been very well taken care of. Fifteen years of driving is an impressive age for a car, but like most 3rd gens, it's been showing some signs of aging, specifically on the undercarriage. I've noticed a great amount of rust has accumulated, specifically on the rear axel and diff. It has also rusted to the point where it seized up my bell cranks. My spare tire's rim is complete rust too. I'm just wondering what the best way is to remove rust and treat/paint parts so it won't come back again. As always, you guys are a huge help. Thanks!

 

[2runnersnyynyg]

sand paper,wire wheel! knock it down then clean surface and spray.
Clean and check the suspension mount points.
I did the tacoma frame spray on mine after cleaning off all the surface rust,it doesnt look like Toyota is gonna step up for the 4runner owners.
and if you dont use your e-brake dont worry about the bell cranks, the job sucks to do. if you use and can fix it yourself ,parts are cheap.

 

[audiness]

I hate to say this, but search.... there have been a ton of threads on this subject already.

you have to remove the rust with abrasion first, then treat it, then seal it. I recommend eastwood.com , but beware their rust treatment stuff is expensive

 

[Kanoe]

I just this weekend used some POR-15 and Chassis coat on mine.

Had spots in front of the rear wheels where the factory running boards had allowed debris to damage. The damage was not obvious 'til the boards came off. Luckily just surface rust, not too deep.

It is a very multistep process, but the results look very good. I wiped some excess from the dish on a couple rusty frame spots too. Only time will tell for sure but that is the case with any system. The Chassis coat is very nice thick paint to work with.

 

[MStudt]

If you dont use your e-brake dont worry about the bell cranks, the job sucks to do. if you use and can fix it yourself ,parts are cheap.

I'll chime in on this. The job is very easy and will only take you about an hour to so. I was able to replace mine without have to remove the rear brake shoes. You can actually pull the adjuster out and get the shoes to move enough to get everything back together. With the parts, if you go to the dealer you could be looking around $100 per side! The other thing is that the dealer only sells what you in individual pieces. I bought a complete kit from O'Reilly's for $45. I suggest buying some extra grease and pack those bastards full of it. If your state is like mine, you can't pass an inspection if it's not working.

With the frame rust, this seems to be a fairly common problem in the rust belt area. I'm going to be dealing with my frame rust in a month or so. The passenger side around the rear lca mount is getting pretty bad. I'm going to be cutting out a section about 16" long to make sure I cut out all the rust. By the way, I bought mine in Toledo Ohio and it has pretty much all the same rust you've described. I wire wheeled my spare, primed it, primed it again, and then painted it with Rustoleum Hammered spray paint.

 

[pattycakes77]

If you look at the Eastwood website they have all kinds of treatments and coatings to work with rust. If the metal is too far gone then these treatments won't do jack for you. But, if you want to knock down the bad stuff, treat it, and coat it then they have some great stuff for that. Not to say that most of it is necessary, they sell a tool and product for EVERY little thing and you could probably get away with doing a lot less and saving money.

I bought a product called Ospho last year when doing my frame swap and it's a pretty decent product. I would knock down the scaley rust, grind, or wire wheel what I could and then apply the Ospho with a spray bottle. It converts the rust you can't get into a paintable surface. You then just rinse it with water and dry it really well, then top coat it with something like POR15. Or, if you have the money and tools you could shoot some epoxy primer and a good catalyzed product (Eastwood's Xtreme Chassis Black is awesome!).

If you use the Ospho wear gloves, a respirator, don't get it on your clothes (or wear old clothes you don't care about), and don't get it on the concrete. It's only for the rusted areas too, if you put it on good metal or painted parts it just looks oily and does nothing.

I used this method on my front spindles and they are still looking great. I used an alternate method on my rear axle and links and it failed almost immediately.

 

[woodro]

i had alot of rust under my 99 , i removed the fuel tank and exhaust and i sanded any rust on the frame and then coated with pro-15 . i also removed the complete read diff and upper and lower control arms and had them sand blasted and then coated with por-15 .
probably took it further then most people would but rust is like cancer if you dont get rid of all of it , it will just come back .

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[shadyluke]

i had alot of rust under my 99 , i removed the fuel tank and exhaust and i sanded any rust on the frame and then coated with pro-15 . i also removed the complete read diff and upper and lower control arms and had them sand blasted and then coated with por-15 .
probably took it further then most people would but rust is like cancer if you dont get rid of all of it , it will just come back .

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That looks really good. Even got some new brake lines in there.

 

[afg10000]

I just roll with an alloy rim on the spare so I don't have to worry about it. Learned that lesson the hard way. Got a 6 spoke of E-bay for $25. I do like the POR stuff but like Audiness stated, it can get pricy and messy.

 

[Nelsonmd]

The easiest rust removal is with a pneumatic scaler. Boy do I wish I had one when I first got my rust bucket. All my rust removal would have taken so much less time, I might have had time to go on a date...

POR-15 is pretty popular and is a great product, but you really have to prep it properly. If you don't do a good job of prep, it will just peel right off.

 

[IBallEngineer]

POR-15 is pretty popular and is a great product, but you really have to prep it properly. If you don't do a good job of prep, it will just peel right off.

Exactly, a good metal etcher like PPG DX579 is your best bet. It is toxic, wear good rubber gloves(not latex) that go past your wrist. It takes of the loose oxidation left after descaling. Then you can use any good DTR paint, don't forget to topcoat it with something too!
:couch2:

 

[Salman]

MD/VA 4Runner - stop it before it spreads

I know it is very little but want to stop it before it spreads. When I decided to replace my rear rusted bumper, it was first time when I was under my truck. Bumper was replace in Nov and I bought this truck in Sept last year.

Now, I am waiting for better weather as working in apt parking in winter is hard. For time being I'm spraying PB Plaster. I am planing to use wire brush and eastwood products like Rust Encapsulator, matching spray paint and fluid film.

 

[woodro]

That doesn't look bad at all , you can clean that right up with a wire wheel and some paint .

Nelsonmd is right por- 15 is a great product but does have to be prepped is steps , with cleaner and metal prep .

And wear gloves , that stuff does NOT come off !

 

[Nelsonmd]

And wear gloves , that stuff does NOT come off !

And don't lay on your back while painting your undercarriage. You will end up looking like a dalmatian...

 

[thebrandon]

And don't stare at the sun!

 

[RyanMcCarthy]

i had alot of rust under my 99 , i removed the fuel tank and exhaust and i sanded any rust on the frame and then coated with pro-15 . i also removed the complete read diff and upper and lower control arms and had them sand blasted and then coated with por-15 .
probably took it further then most people would but rust is like cancer if you dont get rid of all of it , it will just come back .

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I'd love to do that. It's just that I'm pretty new to working on cars. Could you explain to me how you did that or possibly link me to a thread showing me how to remove those parts?