OK, I have the sunroof of the '86 420 SEL apart: the slide on both sides is broken (no surprise) and everything looks good, no rust, and very repairable: buy new parts, clean it up, apply Mercedes-Benz lube paste, etc. Problem: there is a guide tube mounted in the back part of the sunroof frame, with a slit in the top. Mine is bent and twisted. If I cannot straighten it to work OK, is it replacable? is it part of the entire cable tube?