Undercarriage rust removal and prevention

[Ucsdryder]

Hoping someone has a little more experience with rust than I do! Being west of the Mississippi I haven’t had to deal with rust on automobiles. I bought a 2017 suv with low miles but it has some surface rust spots on the undercarriage. It looks like a wire brush on a drill will remove the rust. I see other products such as rust converters or something like corrosion X that chemically removed rust.

Once the rust is removed, do I spray the undercarriage to help protect it? I’ve seen some people say rubberized spray is a good thing, and other day in the long run it will allow moisture and rust. Here are a couple pictures. Near the rear bumper, behind the spare tire is the only spot that seems worrisome. The other spots just seem like surface spots to this untrained eye.

 

[Forestryguy]

Personally I would say for a '17 that is not bad, especially for not being undercoated. If you want peace of mind take it somewhere that specializes in dealing with rust issues. Have it undercoated and rocker panels coated in a bed liner. You would still have to hit places every year that those coatings don't get too. Here in the upper midwest there are guys that use everything from WD40, Fluid film, used motor oil to get into every nook and cranny. Some even go as far as putting oil inside their doors.

 

[Sccritterkiller]

I have used POR-15 on a few different projects works pretty well. YMMV

 

[def90]

Honestly I would just leave it, a wire wheel isn’t going to get it all off and then if you go and DIY some kind of coverup it’ll just continue to rust underneath anyway.

If you are serious about fixing it you are going to have to strip the vehicle down just like you would for a complete restoration then have the frame and components all media blasted and then coated. Anything else you do will just be a short term cosmetic fix.

 

[Coldtrail]

Not the most environmentally friendly solution, but for years I know people in the rust belt that fill a plant sprayer with 50/50 trans fluid & mineral spirits and give everything a soak once a year. The trans fluid will creep into and penetrate every nook and cranny after a day or two. Just make sure you have a tarp down to catch the overspray & leave it parked on for a little while.

This also makes the various nuts and bolts easier to deal with in the future too

 

[Gseith]

I live in Ohio, and the rust will kill a vehicle. I have been using fluid film the last few years and it has been stopping rust. This has to be applied every year to work.

 

[cnelk]

Take that thing on some mtn gravel roads for a couple days. That’ll knock some stuff off

 

[yfarm]

How To – Breakaway Tackle

watch the video on beach proofing your vehicle

 

[miketheguymike]

Hoping someone has a little more experience with rust than I do! Being west of the Mississippi I haven’t had to deal with rust on automobiles. I bought a 2017 suv with low miles but it has some surface rust spots on the undercarriage. It looks like a wire brush on a drill will remove the rust. I see other products such as rust converters or something like corrosion X that chemically removed rust.

Once the rust is removed, do I spray the undercarriage to help protect it? I’ve seen some people say rubberized spray is a good thing, and other day in the long run it will allow moisture and rust. Here are a couple pictures. Near the rear bumper, behind the spare tire is the only spot that seems worrisome. The other spots just seem like surface spots to this untrained eye.

I recently restored a '67 f100 and used a good grinder, and power sander, to clear off rust -- then some POR15 to protect.

 

[QuackAttack]

I don’t know if it’s right…but I had the same issue. I hit it with a wire wheel on an angle grinder, spray painted it matte black with automotive paint, and let it dry well.

Then, I went and had it sprayed with the oil undercoat to get in places I couldn’t.

 

[Ucsdryder]

The minor stuff I’m not worried about and can correct. I’m more worried about this kind of stuff. Will it require replacements? What about frozen bolts, etc. I got a SMOKING deal on the vehicle, long story but nobody knew about the rust. I’m trying to save the deal because I can’t replace this deal even in 2019 car market, but I also don’t want the undercarriage to look like Swiss cheese in 5 years. I’m in a dry climate, no salted roads now, so if I can stop the rust I shouldn’t have anymore issues.

 

[Forestryguy]

For bolts just hit them with WD40 every now and then. It will slowly work its way into the threads and keep them from seizing.

 

[WV Mountaineer]

I just did this again yesterday to one of my trucks. I just started doing this last year as I was unknowing on how to prevent rust on the undercarriage. Because undercoat doesn’t. I had tried that before.

I have a friend in northern PA. He has about a 1/2 dozen vehicles. Sone are 30 years old with way over 300,000 miles. They all look like they just cone off the production line. When I asked him his secret, he told me used motor oil.


Get a siphon gun from harbor freight, keep your used motor oil in a clean 5 gallon bucket. Dip that used oil out and Spray that on the underside of the vehicle. It will need coated several times the first year. After that, once a year in fall and you are good to go.

Adjust the gun to spray it thick. Use a painting technique. Initially, it takes about an hour for a big truck. After the first coat, we are talking 20 minutes per application.

 

[jthomas]

Wire wheel it, eastwoods black rust encapsilator-brush on, top coat with any satin black spray paint for a uv protector.

 

[jthomas]

 

[Marko]

I agree on the drain oil spraying every fall. I've been doing it for years with great results. A few years ago a coworker and I bought 2 almost identical trucks. 8 years later he was replacing his box because all of his cross supports were gone from rust and mine were rock solid. Oil creep into all the crevices as compared to some undercoating applications just creates spots to trap moisture.

 

[LCsmith]

Fluid film, woolwax, pb blaster surface shield, etc. Are all lanolin based products that never dry which impregnates the metal and prevents rust. You can buy a woolwax kit for under $250 on Amazon.