Brake Pad Wear Light W124

[glenmore]

Couple questions for the forum:

My brake pad wear light is flickering occassionally but not when applying the brakes going forward, only when applying the brakes while backing up. Does this indicate new pads are needed or something else?

All my rotors have lips on them but seem to be within wear limits as suggested by the "3 coin rule" mentioned in another thread.

Do these lips need to be removed before putting in new pads? How does a DIYer do this? Take all the rotors off and take them to a shop?

Thanks,

glenmore
1991 300CE