Rear Subframe Rust

[jco897j]

I was under my car investigating some rear alignment issues (alignment shop claimed one of my adjustments is seized up) and noticed I have a good deal of rust on my rear subframe. I've attached some pictures. Car is originally from the Chicago area. Do you guys think this is a wire wheel and por15 situation or should I be considering replacing the subframe?

Thank you for your time!

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[old guy]

Buy a gallon of Fluid Film and coat the hell out of it.

[jco897j]

Is there any difference between fluid film and por-15? Similar products?

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[old guy]

Is there any difference between fluid film and por-15? Similar products?

Very different products. Por-15 requires a lot of prep and dries to a hard coating. Fluid Film is a lanolin based product that requires little to no prep but will have to occasionally be reapplied, depending upon driving conditions.

[19birel]

Personally I would hit that with a wire wheel to knock the rust off as best as possible, blast it with brake clean it up, then coat it in Por-15 to protect it and renew the finish

[Theiceman]

Yeah mine looks that bad too. I was shocked with the poor quality of metal / treatment used under these cars.

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[Chillaxin]

You need to apply a rust converter after removing loose paint and rust. After the rust converter (which is a type of phosphoric acid), then you coat that with paint or undercoating. That will get you the longest-lasting protection.

[MongoMcG]

POR-15 makes a decent rust converter product called Metal-Prep (formerly Metal Ready), which contains zinc and phosphoric acid. After the acid etches the metal it dries to a zinc-phosphate surface that is decent for coating. You must keep the surface wet with Metal-Prep for 20 minutes or more. Before the rust converter goes on the loose paint must be eliminated and the rust must be de-scaled and minimized (not removed because the product needs the rust to work), and the surface must be de-greased using a product like POR-15's Cleaner Degreaser (formerly Marine Clean) and rinsed with water.

[old guy]

All those suggestions are good, but require a massive amount of work. As I previously mentioned, Fluid Film is a dirt simple approach to stopping and preventing rust.

Spend a few minutes reading through the Fluid Film FAQ's and see if it might be the right application for your needs. Also review Automotive Applications