Underside corrosion management/prevention (1 Viewer)

[dparnas]

Bought my 97 LC back in August of 2021. The paint and the interior were in great original shape, but I posted some pictures here back then of the underside. The visible rust was concerning to me, but most people here just said hit it with fluid film and enjoy. So, last Summer, when it was nice and warm out, I did some underside cleaning first, then sprayed about 3 cans of fluid film to the underside. But since then, I've had the opportunity to do some other work on another car of rust prevention, where I used a wire wheel and then some rust converter and found it very satisfying, so now that it has been a year, I'm going back in tomorrow to do the same thing with a wire wheel and rust converter. One of the things I ended up doing was removing the old side steps that had really really bad rust. I found someone here on mud that had a used set that was in pretty good shape. That was part of the process where, while they were off the car, I took care of the underside of the side steps so that they would be good for years to come.

Here are some of the original pictures I took. Any recommendations for areas/parts of the underside in particular I should focus on for this process and other parts that aren't of concern? For example, the rear diff casing and axle looks pretty bad, so was planning to make sure that gets a good treatment.

 

[pgmatt]

If you really care you can find shops that will blast underside with soda or similar to remove surface rust, inspect and apply a good high quality chassis paint. Alternatively keep doing what you are doing and apply fluid filM or similar liberally yearly.

 

[dparnas]

If you really care you can find shops that will blast underside with soda or similar to remove surface rust, inspect and apply a good high quality chassis paint. Alternatively keep doing what you are doing and apply fluid filM or similar liberally yearly.

I'm gonna do the work myself. I enjoy it. Any recommendation for a high quality chassis paint, after the rust converter cures?

 

[Tower1]

I just did this to my hundy last year every thing I could reach with a grinder with a brush/ wire brush . Jacked it up , took off the tires , put it on jacks and began. I degreased first and used a power washer then used simple green and power washed again then started the grinding process I used the POR 15 process and was really pleased with the results , just keep in mind the POR 15 is as nasty as it is tough , if it gets on you it will have to wear off. If you go the power washing route pay close attention to all the drain holes in the frame . After I finished the painting process I then used the fluid film treatment . Wished I would have had easy access to the soda blasting for that would have saved a lot of time. I recommend buying the small cans of POR 15 it starts to cure as soon as you open it and small 1 inch disposable brushes from harbor freight. Good luck with your project and have fun

 

[Kernal]

Try a search, there was one person who had a shop soda blast their undercarriage then the shop applied a type of tough epoxy paint used for bridges IIRC.

FWIW

 

[SpenserAK]

Personally I would never use a paint-style product (such as POR) unless it was on absolutely clean, blasted or nü metal, like a frame-off restoration.

The fluid based treatments are where it's at, for the vast majority of situations. But that's just, like, my opinion, man

 

[Saito]

I’d replace those brake hard lines as the first order of business. They look pretty crusty and my LH side broke the second I touched it when I was putting my lift on.

Oh, and get a good needle scaler. That’ll remove the rust quicker and I’ll bet you’ll enjoy using it too. It’ll also peen the metal which supposedly strengthens it . . .

 

[pgmatt]

I'm gonna do the work myself. I enjoy it. Any recommendation for a high quality chassis paint, after the rust converter cures?

Personally I used rustoleum and just touch it up when needed but there are some really high quality options out there depending on how much you want to spend and prep is probably the most important thing to ensure it can bond properly. I went on partsouq and ordered boxes of all new hardware, brake lines etc as I was doing a chassis refresh primarily but felt for the $1000 investment it would make future servicing much easier and might as well clean and respray the chassis while doing mechanical work. Another good idea if not mentioned is to get bumpers off and run a long wand or traveling wand down the frame and after dry apply wax/oil etc inside the frame rails and body cavities that are collection points for water etc. There are some threads on here if you search discussing different paint options and some people who know allot more than me about it have detailed products and application techniques. Its not the funnest job so might as well just go all in and do it once and not have to think about it again.