The rears seem to be the most likely to break. Because of how the track works on them, they have a lot of force in various directions as the window goes up and down and the design of the slider is relatively fragile. I appreciate that the engineers were trying to make something quiet, but the UHMW glides I made certainly don't seem to make any noise, so not sure why they didn't do the same thing.

If you have access to it, the UHMW plastic is exceptionally durable stuff. Self-lubricating, wear-resistant, and tough as nails.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)