Replacing Crankshaft Counterweight

[DavidBrough]

I’m in the middle of replacing my front crankshaft oil seal which has been successfully pressed into place and I am now ready to replace the crankshaft counterweight. As I have already had one unsuccessful attempt, is there a trick to doing this and correctly aligning the locating pins?
 
All thoughts & suggestions gratefully received.



David Brough
1969 280SL Auto with A/C

[ja17]

Hello David,

As mentioned, make sure you are indexed correctly, the pins are slightly off set so you will not get the unit off 180 degrees unless you really force it.

To install align as close as possible, then tap the counter-weight on (protect with a block of wood). Leave the pins out.  Once in place the counter-weight can be adjusted by rotating it. Use a wooden rod as a drift and hammer to rotate it until the two pin holes align exactly. Drive the pins in place. Torque to specs.

Joe Alexander
Blacklick, Ohio

[DavidBrough]

Thanks Joe, my counterweight is such a tight fit on the crank that I couldn’t see it turning to align once in place.  I may have to clean it a bit with some emery paper then try again and adjust as you suggest.


David Brough
1969 280SL Auto with A/C

[ja17]

Hello Dave,

They all go on tight. Try bumping it around, you will be surprised. I would not do anything to loosen up the fit. Do some minor adjustments as you are tapping it on.

Joe Alexander
Blacklick, Ohio

[DavidBrough]

Thanks Joe, whilst on the topic, is there an accepted way of counter holding the engine on an auto when tightening up the centre bolt as 150 ftlbs is a lot of force. I do have a good air wrench but this doesn't have a specific torque setting.

David Brough
1969 280SL Auto with A/C