You can get away with replacing the plastic slide once or twice.

The regulator eventually becomes twisted.

Replace the regulator. It's easier than replacing the slide over and over.

__________________
'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E