PeachParts Mercedes-Benz Forum - View Single Post - 1980 W116 300SD OM617 Front Crank Seal Replacement

Squiggle Dog · #3 02-10-2013, 12:12 AM

Once the six pulley screws are out, the pulley and balancing disc will come off, so it is important to hold them to prevent them from falling and causing damage to anything or themselves. I don't know if it's necessary, but I marked the original position of the pulleys, balancing disc, and harmonic balancer to each other with punch marks. As you can see, once the pulleys are off, there is plenty of space to work around in.

No need for the extra headache to drain fluids and remove the radiator and oil cooler.

The 27mm crank bolt is torqued to at least 270nm (200 ft-lbs), so breaking it free after many years is very difficult. I did it the easy way--make sure nothing is blocking the crank from turning (remember the socket extension that was wedged in to keep it from turning?--remove it). Then I positioned a breaker bar wrapped in cloth against the frame rail and bumped the starter. Make sure the socket is fully seated on the bolt. This breaks the bolt loose with minimal effort. The breaker bar did fall back and rest on top of one of the transmission cooler hoses, but it didn't cause any damage.

Here is what the harmonic balancer looks like with the fixing pins. Make sure to mark the position of the balancer on the crank with punch marks on each. If it is installed 180 degrees off, the engine will be out of balance. If the old balancer is damaged, the replacement must be match balanced to the old one.

I didn't have a harmonic balancer puller, so I rented one for free from my local auto parts store. I used a generic one and it worked great. There was plenty of room to use it. The balancer came off slowly but smoothly. Make sure it doesn't fall to the ground.