Having seen a PHer's posts about crusty rear arches on his E91 I decided today was the day to take a look at mine, even though I feel like crap and it was damp out. I wanted to check the rear wheel bearings anyway as it's developed a hum since I had the PS5s fitted - I wondered if the rear caliper sticking enough to smoke and crackle had maybe cooked the bearing. That seems fine thankfully. Just need to check the front bearings.
n/s rear arch first and yep, crust ahoy
Gave it a wire brushing first and thankfully I seem to have caught it early enough that it's still just surface rust and all fairly solid. I recently bought some Bilt Hamber Hydrate 80 rust converter, some Electrox zinc primer and some Dynax spray wax- all to tackle the tailgate rust that I haven't yet started. So I set to with the Hydrate doing arch, subframe mounting points and the area around the threaded stubs for the arch liners.
o/s not as bad thankfully but the subframe mounting point was slightly worse. So it all got slapped with the Hydrate
I also noticed surface rust around the battery tray area and inside the tube that the fuel filler breather hose passes so slapped some in there.
This exposed area of the subframe mounting points is the bit that concerns me the most. They really are fairly crusty on the surface and have no protection. This is before taking off the liner and cleaning up - you can see how exposed this area is
Hopefully I'll get chance later this week to use the Electrox and wax.
And just a word on the arch liners - fronts are plastic but the rears are a fibrous material like felt. Seems absurd as even without a build up of crud, they get sopping wet and sit against the metal. Even now 6hrs later after a good scrubbing they're still.pissed wet through in the garage. Plastic would at least allow some crud to wash out and would allow it to dry out quicker. Seems bizarre to me.