Yukon

So I just got my 4runner, and I'm thinking ahead and wondering about undercoating to prevent, or at least slow down rust. It already has a bit, mostly surface around the welds.

I searched a bit, but was wondering what the best way to go about this. POR-15 is expensive, but sounds like its worth it.

Ive never really done anything like this before, what parts do you paint, can you do it without taking the whole car apart? I have a driveway and jackstands for tools.

Theres the picture of the worst of the rust.


Could I just paint over it, what prep work is involved? Is it worth the time/effort?

How much POR-15 or better product would I need to coat the whole, or at least better part of the underside?

Thanks for putting up with the questions?

pattycakes77

iTrader: (2)

i bought 2 quarts of Por 15, a quart of the Marine Clean, and a quart of the Metal Ready. now, i would definitely recommend you do the POR 15 treatment before doing any undercoating. i had mine undercoated a few years back and now i'm trying to take it off as much as possible to treat with the POR 15, works a lot better the other way around. as for the POR 15 amount, i haven't even touched the second quart yet and the first quart is more than half full still; after 3 coats on my old calipers, a few misc car parts, and 3 coats on my 1st gen roll bar. a little bit goes a long way, but you may need to buy more of the Marine Clean and Metal Ready. however, once you open it, it will start to solidify slowly even if you do as the directions say and put some plastic wrap between the can and lid and keep it in a cool place. i came back after a week of not using it and there was a "crust" on the top inside the can. i would say you could probably get away with one quart for your undercarriage. as for how to use it...
get off as much of the loose rust as possible with a flat screwdriver, wire brush, or some gritty sandpaper. then mix the Marine clean 50/50 (or less) with warm water (use gloves!!!) and clean everything you'll be painting with the marine clean and rinse with water. maybe dry it with a towel, let the heat evaporate the water, or use compressed air to blow it dry. the bottle says to use the Metal Ready straight, and keep parts "wet" with the product for at least 10-15 minutes, or longer if they are heavily rusted. a spray bottle would probably be best for this under the vehicle. then rinse with clean water, dry as mentioned above. then it's time to lay some tarps down (if you don't want your driveway/garage/street covered in POR 15. might be a good idea to cover yourself thoroughly too, and definitely wear gloves or you will be POR 15'd for a month. now, crack open your quart and start painting! do a light coat, wait a few hours, do another light coat, wait a few hours, and then do another light coat and be done. don't do a heavy coat or you will have lots of drips and sags and it will take longer to dry. i'm not sure about moving parts or threaded bolts etc with POR 15 put on them, it dries pretty solid so if you paint it on something make sure it's not a moving part or a part that you will have to replace down the road or it will be harder to remove.

and, no you don't have to disassemble your entire car to use POR 15.

it's quite a lot of steps and waiting and messy, but if you want it sealed for a long time you'll have to struggle a little in the short term for long term protection.

hope this helps you

camp1

I live in northern Maine where we have harsh winters and the municipalities and state road crews use a road salt to keep the ice build up down. IT rusts the hell out of your under carriage. I have owned toyota's all my life and have always done well with Dupli Color Asphault under coat or the NAPA brand asphault coat. I don't buy the rubberized stuff because it just peels off. I pressure wash the undercarriage, scrape off any loose rust flakes, pressure wash again, let dry and spray every inch of the underneath of my toyotas. It takes about 12 cans at about $8 a can for the first application. Each spring I pressure wash again and re- apply. It takes less cans each time you do it. The entire undercarriage, inside fenders, frame, inside bumpers and around all the axles is black. I have also sprayed used motor oil in the frame rails. I take my undercoating serious because if I didn't my toyotas would rust out before the motor would quit. This is a less expensive option that has worked great with me. My 1995 4runner has no rust at all under it because I started undercoating when I first got it and kept up with it each year.

E30RUNNER

I will also be using POR-15 on my undercarriage, but have been putting it off until the end of the summer just cause the heat makes me lazy. But either way this is what I bought:

http://cgi.ebay.com/ebaymotors/ws/eB...EF:MOTORS:1123

But according to the research I've done it's quite a task. I will post my results once I do it.

corax

how do you get the inside of the frame rails?

RunnerUp

how long is a coating of POR 15 good for? i dont have any rust on my undercarriage but dont want to get any either...

DailyDrive

If the vehicle is not new, best path is to spray with oil, and spray often. Everything else will just seal rust in and make things look pretty. It will be worse in the long term.

Yukon

Wow pattycakes thanks. thats helpful. The truck is 9 years old, and spent its life in Illinois so it is Rusty in spots, but it all looks like surface rust, and I want to keep it that way.

Looks like I need about 1qt of POR 15 for now, probably that kit JRB linked to. I want to get the axle, and the front A arms done, then move on to frame rails, and places brackets mount to the frame, as these areas seem to be rusting most.

Spraying with oil will be hard as I'm in school during the winters, so its hard to keep old oil in a dorm room.

Any more input?

312necro213

Daily drive, if you read the back of the can on POR-15, it does say it will seal in the rust, but what you said is wrong, rust forms from a reaction with oxygen, POR-15 seals in rust thus sealing out Oxygen, therefor the rust is still there but without Oxygen for the metal to react with the rust cannot advance any further, the only reason they even have you remove the rust is so you get better adhesion. POR-15 will be your best bet with rust prevention.

DailyDrive

There's theory, and there's reality. The theory part is on the back of the can, yes. But the reality is any sealer will eventually chip. Usually in places where there was the most rust before. Once water gets in behind the pretty sealer, it will continue rusting either until your metal part is rusted through, or until the pretty sealer falls off in big chunks and you finally notice the horrible rusting below.

BajaRunner

There are some other products which are POR-15 like.

Three of which are:

Zero Rust
Rust Bullet
Rust Encapsulator

I just bought two quarts of Zero Rust. Apparently its a heck of a lot less toxic than POR-15, and is safe to spray if you are interested in that, rather than painting with a brush.

Prep work is key. Marine Clean and other products like Naval Jelly all use the same active ingredient: Phosphoric Acid. You can buy this stuff super cheap at Home Depot and mix up your own batch, rather than spending a bunch of money on a pre-made product.

I would take the time to whire wheel/brush everything before, then use the acid to neutralize the rust, then use your rust preventing sealer.

Mason Dixon

u can buy little bottles of por 15 type rust stuff at autozone for about 6 bux a bottle. mine looked just as bad as the op's. Took about 2 bottles(which also went to some of the front end rust spots as well) it really helps to take off your spare tire and jack your backend up a couple of inches, you can sit indian style quite comfortably back there and really get a good coating on. I'm going to add a 2nd coat this fall when it cools down and then spray paint with some flat black rustoleum.

Yukon

So it seems pretty agreed that it is worth spending the million dollars to get POR15? Is there a cheaper alternative that works as well?

BigBallsMcFalls

for inside frame, instead of oil, spray with Boeshield. it creeps well and lasts a looooong time, far longer than oil. but it costs a lot. it dries to a wax-like gunk. good stuff

http://www.boeshield.com/

camp1

Question about how do I get oil in my frame rails-

I put my truck on a very steep decline and spray it down the rails from behind the rear bumper with a garden sprayer. IT all runs forward and then I spray in every hole in the frame (mfg hole). I use a sprayer with a flexible hose so I can stick in in the frame holes. It is not the best but the cheapest. I use my used motor oil. MY way of recycling. HAHAHa.

pattycakes77

iTrader: (2)

went to their site, sounds like good stuff. i'll probably buy some for inside the frame when i'm done with the POR treatment, then try some of that asphalt undercoating as suggested to seal it all in real nice. like a big cozy blanket to tuck in the rust for a looooooooooooooong night sleep. i also thought it was funny that boeshield is © PMS Products Inc. , nice acronym.

rocket

iTrader: (1)

POR-15 sealer does not "fall off in chucks". It actually works like the label says. Rust cannot continue if the metal has has been sealed. I'm amazed by how it reacts to anything it touches.

rocket

iTrader: (1)

In comparison it's not that expensive. I've spent more money in POR-15 products to use on my Shrockworks bumper than it would of to have it powder-coated for $90. You'd be surprised just how long a pint will go and how durable the finish turns out.

rocket

iTrader: (1)

POR-15 sealer can be brushed on with no effects from toxins.

Their Marine Clean ("non-toxic") formula is more hardcore than brake fluid...the fumes alone are very brutal and any residue left on your skin feels permanent and slimy when trying to wash it off.

pattycakes77

iTrader: (2)

yeah, there are also instructions for thinning the POR to be shot through a paint gun if you have one. i'm sure the masking off would take more time but it might go further into places you can't get to with a brush and look a little nicer if that makes a difference. and OMG, that non-toxic stuff will eat your skin! i spilled a little on the palm of my hand and after the slimy went away, so did about 3 layers of my skin over the next couple days! i also have the black POR 15 paint on my pinky finger from a month ago, wear gloves!!!!