Bodywork advice

[Black9]

My E39 M5 was in the garage around June time for a full respray and various mechanical work.

I left the car with them for around 8wks so more than enough time to sort the bodywork 100%, a few months later I noticed some corrosion on the lip of my rear arch so sent the car back in to have it sorted, which it was, for free.

Having a look over the arches again I've noticed another small rust spot appear on the lip. My Q is should I send the car back Into the garage and have it sorted FOC or should I expect to pay for it?

I know it's an old car but surely rust shouldn't be reappearing so soon after having it sorted?

Any input welcome

[garrardrj]

Depends on alot of things and what you asked for when leaving the car with them . Rust should not come back through after such a short period of time , but if you had it done on the cheap then that could happen

[cuprajake]

You cannot guarantee rust won't cone back unless you cut out the effected metal.

It can take 6 weeks or 6 months to reappear. If it's not cut out,  it will come back.

[greygti]

Yep I'm with cuprajake on this,in my experience/s  you've gotta cut out the affected metal as rust WILL always come back and I've had plenty on experience on older honda type R's and other cars.

Simply grinding back the rust and treating it just won't do it'll just be a matter of time before it returns,if it's rear then either arch repair kits or worst case quarter panel/s or front new wing/s

[gobbleplease]

To be fair I think it's all to do with the prep, at the end of the day most paint shops don't really give a fcuk they remove it put some convertor on prime / fill then paint - I've had rust done on a couple of older cars, only for it to reappear twice in a couple off months. I went through this twice then done it myself and it never returned while I owned the car - if you are doing it correctly it takes time and and the right products which costs money which seems to go against most paint shops priorities when it comes to rust.