BMW undercarriage rust
 

https://cimg7.ibsrv.net/gimg/5series...d29a38a6ab.jpg
BMW factory has sprayed the undercarriage with a silver primer paint.

There are a number of places on the rear of the car that are rusting and need to be reSprayed.

Has anyone color matched this paint?

What brand and color did you use?

See picture.

Assuming you’re mistakenly referring to the aluminum parts as silver primer paint, the rust you see are the steel parts that are rusty I just maintain that be spraying them with some rust retardant like or oil etc. Whatever your local hardware store has

I tried to find that same silver color that is sprayed on the rear sub frame and I couldn't find it at the local stores.

I was hoping someone order silver primer spray paint in the can from an online store and knows the exact store and exact color.

There may have been a zinc coating on that hardware, but no more. You DO NOT want to paint these bits. You will be applying paint over rust and this will do nothing to stop corrosion. It will likely accelerate corrosion. Do as suggested and treat them with Fluid Film or similar product. The idea here is to halt more corrosion and make the parts easy to disassemble and service. If you want shiny new bits, buy shiny new bits!

I just checked out Fluid Film spray. Wow, that stuff looks powerful.

Thanks.

I've done all those rusting bolts under my car with Fluid Film - sticks really well - seems to work well. It would be worth the effort to try to hit all the steel heat shield fasteners - up above the rear differential / anywhere you can reach as well.

Did you try to wire brush or remove the existing rust from the rear sub frame before spraying it with fluid film (or did you just spray the fluid film over top of all the rust)?

https://cimg5.ibsrv.net/gimg/5series...a939c3a5b.jpeg
Fluid Film has been my fav for a long time but I recently picked up a can of AD3000 and got to use yesterday first time on some rusted galvanized nuts of my wharf ramp, being on salt water never thought I would be able to unscrew them easily but to my surprise they instantly became grey again rather then rusty dark brown.....

so so if you can find it where you are suggest you give it a try on the bmw(I got it here at princess auto), being in Canada.

ok, I'll order some AD 3000 and see how it goes.

Some of the Fluid Film videos suggest that it wears off after about a year and needs to be re-Applied.