hi guys

iv been stripping back my chassis rail under the battery box i buffed off the rust treated the rust and put 3 coats of zinc primer but some surface rust has now showing through the primer, should i strip back and do it again? think i left it to long after applying krust(over night) plese find attached pictures

Personally I'd strip it back again to make sure it's all gone. Then rather than just the zinc primer paint it up again after for more layers of protection.

It's only surface rust. But it's good to treat with zinc