Frame rust surprise - 3rd gen manual

As I was prepping the frame to be painted for rust converter, I noticed holes in front passenger side right next to the oxygen sensors.
I checked other common areas like the rear control arm mounts and didn't see any major issues there. There is rust but it's just surface rust that I was able to clean and will spray it with rust converter once I decide what brand/type to use.

For the area that does have holes in the frame already, what should I do? I have never welded before. I do all work on my own and has done a lot to this car since I got it a year ago but I have never welded.

See pic of the area that has rust. Please let me know what you think I should do. I am not trying to spend a lot of money taking it to a shop to weld. If I would do that, then I might as well get a new frame and swap since there are a lot of surface rust on other areas.

 

Rust converter doesn't work, and painting over rust wont fix missing material. There are chemical ways to remove rust, but rust converter isn't that, every one I've seen tested fails.

What you should do it remove the rust with a wire wheel until you find shiny metal (you'll need that for welding anyways), depending on the damage you have 3 options:
-Use a product like Safe-t-cap which is preformed metal to weld onto the frame
-Weld on metal yourself
-Prime and paint the metal for protection if the frame is solid or you want to roll the dice

You could replace the frame, but nobody who lives in an area where frames rust out like that also lives in an area where there are lots of 20 year old 4runners with pristine frames, if they are pristine they aren't in the junk yard you'll be picking from.

That doesn't look horrible as far as rust belt vehicle go, but I wouldn't leave it either. But if that's the only spot and the rest is surface rust I'd get it welded up and remove the surface rust everywhere else and repaint it. If you want it to last. You could remove the rust yourself, it's time consuming but DIY, depending on how much you value your time.

 

I have been spending a lot of time getting this 4runner back to shape. I replaced all front and rear suspension components, did front and rear brakes and upgraded front to the tundra drum and caliper. Replaced the whole interior including floor carpet and headliner.
So, I dont mind spending the time to do it right.

What you said is exactly what I was doing. I was using a wire wheel to clean the frame from the rust and that's when I discovered the holes I showed in the pic I sent and that's the only spot I found.

If I knew how to weld, I would definitely do it in a heartbeat. Im actually considering buying a welder from harbor freight and practice until I get it some what acceptable.

What should I use to paint the frame? Thank you for sharing your experience with rust converters.
Please let me know what would work best for rust prevention. I live in Michigan and we get a lot of snow and off course that comes with a lot of salt.

 

I would look in to safety cap they make sections of frame that can be welded to the original frame providing there's enough not rusted frame to weld to. My frame maintenance routine is a wire wheel on a drill, hand wire brush for those hard to reach areas, Ospho rust neutralizer , Eastwood black Chassis primer 2 coats, Eastwood black chassis paint 2 coats, Amsoil heavy duty metal protector or Wool Wax. It's all in the preparation take your time. I would look at your A/C drain line coming out of the firewall and get a hose to extend it down past the frame. My .02 G.L.

 

Thank you. I didn't think about the A/C drain line. I will do that today.
How long have you been using this frame maintenance and have you experienced any issues with rust?
Since I have never battled rust before, I would like to follow someone's method based on their experience and their results.

 

I don’t think there’s much in the way of method with frame maintenance. It’s mostly vigilance, cleaning off mud/salt inside andout of the frame, and touchup when you notice surface rust. Woolwax or other wet-film anti-corrosion products help in preserving an already good frame, but you still need to get under there at least yearly to keep an eye on things. Mine is totally coated in woolwax, but I usually do some level of inspection whenever I’m underneath doing other maintenance work. That’s when you catch that mud clod you missed, worn off paint from gravel erosion, and paint flaking off/rust developing somewhere. The idea is to catch it early. When I find a rust spot, I clean off the woolwax, clean/wirebrush the spot, and spray some paint on it (or brush on rustoleluem paint in a can.

Frame repair is another ball of wax. Depending on where it is, you might use various wire wheels/wire cups, hand wire brushes, chemicals, Like already mentioned, prep is absolutely key. Removal of rust to shiny metal is a lot of work, but necessary to ensure your patch is on good metal. The rest of the rusty areas on the frame is the kind of work that doesn’t have a defined end…you could go on forever. So you’ll have to define what “good enough” is so you don’t go crazy.

I have used rust converter on rusty mild steel before, and I’m not all that impressed by what it can do for you. It did appear to stop rust on the spots it was applied to, but sometimes rust doesn’t stop where you think it does. Seems like the rust just kept happening around the areas I used it on. Also, rust converter is a royal pain to remove. Even with a grinder/flapwheel, it was slow going.

 

Looks like rust from inside frame also. This frame is slowly dying. Key question is how long do you want to keep this runner?
I do not know how to compare time/costs swapping frame to continuous rust treatment, welding repairs etc.
If you get a rust free frame to swap-you can get this runner to last a very long time and have value. Remember it is 27 years old now.

 

I would want to keep this runner forever. This car means a lot to me. I did find a very clean frame for $400.
A swap is the safest route except it's a lot of work. I dont mind putting the time and effort but I'm afraid if I get stuck somewhere in the swap process and can't complete it.
I am putting a lot of thoughts into it. Extremely motivated to do it in my backyard after I read through a thread in this forum or another forum of someone that was successful in doing the swap using jack stands

 

Hungryhawk has a good point, if there is a lot of rust in the frame that could be a real problem. You can make a snake which will flail a chain to knock rust from the inside of the frame, you can paint the inside of the frame they make flexible hoses that spray the inside of the frame 360 degrees with paint.

The thing about the frame swap is while it would probably be easier, you'd suffer extreme scope creep. A bare frame, well you'd be stupid not to give it an undercoat when there is no body or engine in the way. And you're transplanting the body, so you might as well do new body mounts. Same for the engine mounts and transmission mounts, might as well. Then you're separating the transmission from the engine, so you might as well do the clutch and rear main seal. And the engine oil pan gasket, that's something you can't do normally, might as well replace it. Those are just the ones I'd do, there is suspension work that would be easier. And if you plan on keeping it, future proofing it wouldn't be a horrible idea. I don't know what sort of engine hoist or jacks you'd need.

There is no work I hate more than rust removal, I've sawed through the end of a tie rod joint with an unmounted hack saw blade and I'd rather do it again. There are a lot of reasons I say that. If you're willing to invest in a welder, invest in an air compressor and make a home made sand blaster, many parts of the frame will grab a wire wheel or are just too difficult to reach with a power tool.

 

Thanks for the helpful tips. If I decide to swap frames, I am definitely going to make a list of things to replace since it would be much easier having full access.
Seriously considering an investment on a welder, maybe an electric one (seems easier for a DIY projects). My thought is to practice until I get it right. Then, I can purchase the sectional frames and weld into my frame. Not sure how difficult it would be to learn welding but I am willing to give it a try. I do have the courage to take that challenge on.