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525ikicker
02-14-2007, 10:57 AM
hi i have a 525i, and the passenger side front fender has rust on the part with that undercoating on it... my question is could u replace the bottom by cutting and replicating the piece by making a new one out of some steel, drill some holes and spray undercoating on it?

i know u can get fenders for as cheap as 50 dollars but if i could i would rather just repair it...

thanks

jus clark

John B.
02-14-2007, 02:01 PM
I did this with my 90 535i last summer. The lt frt fender just had heavy surface rust on the lower inside area by the rocker but the rt. fender was rusted through in that area. You may also find that the front of the rocker/sill has also rusted through as it had on mine. I bought the clean rear section of a crunched front fender from Rigmaster, cut off the section I needed along the lower seam & welded it to my rt. fender after trimming off the rusted area.

After sandblasting the rust off the lt fender I shot the inside of both with epoxy primer (PPG DPLF) before repainting both fenders.

Before reassembling the fenders to the car I drilled a few holes in the rocker/sill ends, pumped Waxoyl inside & plugged the holes. I also coated the inside of the lower rear fender & outside of the rocker ends with the Waxoyl.

If you live in the rust belt it's a good idea to remove the inside wheelwell covers & the fender rear/lower mounting bolts every couple years & clean out the crap that accumulates in there.

MTechnik540i
02-14-2007, 02:06 PM
hi i have a 525i, and the passenger side front fender has rust on the part with that undercoating on it... my question is could u replace the bottom by cutting and replicating the piece by making a new one out of some steel, drill some holes and spray undercoating on it?

i know u can get fenders for as cheap as 50 dollars but if i could i would rather just repair it...

thanks

jus clark

Cut off your fender edges and/or modify/widen them to clear larger width wheels.