normal clutch wear (mechanical) and free play

[atombaum]

Does normal clutch wear reduce pedal "free play" or increase it? The clutch is mechanical (not hydraulic) as found on a 1957 190 sedan.

Jeff

[vince]

I believe it would reduce the free play. The free play is the distance between the throwout bearing and the actuating arms on the pressure plate. As the clutch disc wears (becomes thinner), the arms on the pressure plate move closer to the throwout bearing (as the opposite end of the arms moves closer to the flywheel).

[ja17]

Hello Jeff,
As I recall, there are some bushings and different supports on that mechanical clutch linkage which wear or loosen with time. This may also account for the changing position of the cluch pedal. In particular there is a flat stiffiner rod next to the clutch adjustment rod which likes to loosen up and cause the clutch linkage to change. Besure to check everything out under there. I believe that the cluch free play should be adjusted to 1/2" to 1".
Hopefully you will not have to deal with anything more serious.

Joe Alexander
Blacklick, Ohio

[Robby Ackerman]

What Vince says makes sense, though my experience is that normal wear increases pedal free play. I find that when I experience difficultiy engaging reverse it is time to adjust my clutch pedal. I adjust the free play in my 1960 190SL to 1".

[vince]

There are two wear issues here. The clutch itself and the linkage (since the original post involves a mechanicaly actuated clutch). Wear on the clutch disc would reduce the free play. Wear in the linkage, as Joe points out, could increase the free play. M-B recommends checking the free play at the throwout arm. I think that clearance is around 4-5 mm (check your manual to be sure - the old Owners Manuals showed how to check this). Free play at the pedal is about 25 mm, I think. If the throwout clearance is correct, and the pedal free play is not, then there is likely wear in the linkage. In practice, I have not seen much wear in M-B clutches (the disc itself) under normal service over 75,000 miles or so.