I am in the same boat.
I have been getting all maintenence up to date and replacing worn parts. I'm hoping that I can keep the rust down to make it to 300k. I am at 153k now.
I met a guy recently that does cleaning with some sort of adjustable pressure spraying system that uses either sand (glass particles) or baking soda to remove paint, grease, carbon etc. from metal. For $100 he could take my undercarriage down to bare metal. I'm considering it but not sure if it would damage smaller parts underneath. I would then recoat the frame, axles etc.
Anybody have any thoughts on this?
..........If you have more money than time...another choice you have, after its sanded down, have a company undercoat it for you...bounse, usually this will come with a warranty. Several companies specialize in this. Zbart has been around the longest...I think since the 1960's. I myself used Line-X when I did my truck. I got a discount for doing my bed and undercoating at the same time. I think it cost $300...with a life time warranty. If anything rust, they pay to fix it. Also, I can take it down anytime to have touch up done for free. My truck is 4 years old...the underneath looks brand new. And that's with 4 years of Ohio winters...tons of salt. Good luck with your project...as long as you get it undercoated...you can't go wrong.
The frames rust from the inside out. And sandblasting or baking soda blasting will do nothing for the inside of the frame. Sadly all that sand or baking soda blowing in the frame holes is another trap for moisture.
^^ Great advice...hidden area coverage, is most critical / and often over looked.
The day I bought my 2000 4Runner SR5, 1.5 years ago / had it wax-oil undercoated, the quoted cost was $110 + tax.
- I asked the owner, do you do inside the frame rails & floor braces? / he said "no"
I said, I also want a heavy spray inside the hard to see underside areas.
- extra material was used / so I flipped him $150 cash, and had the rustproofing done right
After 2 winters, the wax-oil product is still wet, on the frame rails.
- Krown & Rust Check products, would have been washed off in a month / water soluble product
- a wax-oil spray (like fluid Film) offers far better undercoating results
That pic doesn't show much of the frame. And, as said above, they rust from inside out. One area you want to test is the floor inside the rear lower control arm bracket. It's a high stress area and a focus for corrosion. Sort of the canary in the coal mine. Take a screwdriver and try and punch through going around the arm. If you can, disaster is not far away. (Maybe read the link in my sig below to see what that is like.)
Actually the frame is in decent shape thankfully. The axle and bumper seems to focus the rust, maybe there is some cathodic protection going on there? There is surface rust on parts of the frame which I will clean up this summer and inside isn't too bad at all, I have poked around especially around the control arms.
Then that isn't too bad. Rear diffs can get a lot worse than that and keep going, and the one really vulnerable part, that thin pumpkin, has either been replaced or protected. A little care and you're in good shape.
Bumpers are junk and easy to swap.