I have a 1997 C280 and the rear headrests are stuck up. I hear the release when I press the button but the headrests will not move down. Any ideas on the fault???

a loose vac line by the oil filter holder. It connects under the intake manifold, and get unplugged when changing filters.

Thanks NHAndy. That was the problem. I'll be more care the next oil change.

do you run in Buffalo? Steel or alloy wheels?