I am seeking suggestions on how to minimize the amount of rust on my 87 4runner. I am living in Portland, OR now where they don't salt the roads. I am moving to the midwest where I know for a fact they salt the hell out of them. I know that by driving in the snow it is inevitable but I would just like to keep my truck as nice as possible for as long as possible, Thanks

por-15

I second that, por-15 is your friend.

Oil - new or used. Spray it underneath and into doors etc. A bit messy but it will drip out and be ok until the next time you do it next year. Drill some small holes into things like doors so that you can feed a plastic tube in and then pump some oil in.

I used Por-15 before. Its good on surface rust but it does nothing for 84-88 beds. I tried putting this stuff on my old truck and it still rusted. Any rust prevention paint should be tested in a midwest winter before being able to make the claims por-15 makes I am considered just getting a beater with a heater for winter driving. But then I think "I have a 4x4, whats the point in storing it away when I need it the most".

Nothing beats oil for older rust prone cars/trucks. I do this in the fall when it's dry...drilling holes if needed...getting it in the rockers/frame channels...door bottoms etc. Sounds like the frame also for these trucks... Use drained ATF.

This won't work where it washes off...like in wheel wells. There I use the alum/plastic/tar/rubber roof repair stuff on a roll...sticks very well on a clean surface...this or roof tar & fabric.

I have to agree with the oil thats what we use in the navy for corrosion prevention. We also use this stuff called grade 1 its a really thick compound that you would brush on you frame rails and such. Ill see if I can find out how you can get it.

I wouldn't use POR-15 in the midwest... I've spend hundreds of $$ on it with little success. The problem is that it peals, and if there is even a hint of moisture under it when applied, you're hosed.

What I would do is the following:
Coat the inside of the frame with a nice thick coat of used oil.
Have the wheel-wells Rhindo Lined or Line-X'd (Do not use a home-installed liner). Have the interior of the wheel-wells / quarter panels lined to seal all seams.
For the undercarriage, I'd clean up everything and spray it with a good epoxy primer, sealer and top coat of chassis black.

Then find a car wash that sells unlimited washes (usually $30-40/month) and take advantage of it.

por-15 is all about the application process. it doesnt work on painted metal it has to be bare. and the reason it doesnt work on the beds is b/c it doesnt coat the inside of the seams.

I agree, I have had good luck with POR-15- if the surface is properly prepared. I have also had good luck with Hammerite (made in England and hard to get), which takes less preparation and rolls on nicely, and does not require an overcoat of UV-resistant paint.

One area often overlooked on 1st-gen 4Runners: the inside of the rear wheel wells. What happens is, as the interior heats up, the moisture condenses on the inside of the cold metal body, then dribbles down to the base weld of the wheel well where it starts to rust. You can pour some sort of solvent to remove splooge from there, let it dry, then pour a good paint in. Warning, you will find all the pinholes and dribble all over your garage.