Harmonic Balancer Replacement
 

My dear old 81 240D threw a crank bolt last week. It missed the radiator but completely ruined the Harmonic Balance by spinning loose against the crankshaft seal spacer. I guess I can feel lucky that it did not come off completely while I was driving down the interstate.
I just ordered a new one from Philip here at Mercedes shop, he even works on Sunday,what a great bunch of guys they are.
My question to the Techs is : Since the new one has to be matched in weight to old one , is static balancing the best way to go. I had this happen one other time on another one my MB's, but the shop that I used back then to transfer the old to the new has gone out of business. Has anyone here on the board had to do this lately. :rolleyes:

I can't answer whether this is an externally or internally balanced engine, but I want to ensure that you know how to put the new balancer on properly.

First of all, I hope the crank snout is okay. There are two steel dowel pins that key the balancer with the crankshaft. If the front of the crankshaft is chewed up and the half cylinders for these pins are screwed up, you will be screwed as well.

IF the crankshaft is okay, do not simply place the balancer on the end of the crank and tighten in place with the bolt. This is very possibly what caused your failure to begin with.

To install it properly, you will need a harmonic balancer puller. Place the balancer and pins in place, with the balancer slightly counter clockwise of where it needs to be to align the pin holes. As you draw it down with the bolt, it will turn slightly. Draw it down a few turns of the bolt, then remove the bolt to see if it is aligning properly. If the balancer reaches the pins and is not perfectly aligned, pull it and try again. Under no circumstances should you continue to tighten the bolt if these pins don't perfectly align. You can and probably will destroy the front of the crankshaft.

Best of luck,

MBJoe - If you find you need a new crank I have one from a 1980 model that looks to be in good condition. Email me and let's agree on a price. I can get you the engine number to confirm that it will work.
Let me know.