There is an old part and a new part. The new part is longer; if you don't have it, get one. The part number is MB Part # 000 074 26 74....Bosch # 1 420 560 014. The old part was supersceded in 1983. Most parts guys aren't aware there is an "old" part, they only have one - the new one.

You only want to do this with an engine as near to perfect as you can get: valves adjusted, all filters and fluids renewed, no chain stretch. Get all that right first.

Look at the injection pump from the driver's side of the engine compartment. Now look at the "gap" between the rear of the pump and the oil filter assembly. You're in the neighborhood. On the back of the pump, the side facing the oil filter housing, will be what appears to be a bolt with a similarly sized locking nut on it. That's the damper screw.

To set it correctly the engine must be at operating temperature, so prepare to get a few burns in the process.

The bolt head is 12mm and the lock nut is 14mm. Loosen the lock nut then back the whole bolt out. Remove the lock nut from the old damper screw and run it down as far as it will go on the new one. Put the new one in the hole and thread it down by hand until you feel it touch something.

Start the engine. It will almost certainly rock wildly from size to side, who knows? Anyway, turn the new damper screw in a small amount at a time and see how the engine idle goes. It's remotely possible you might screw it in all the way before you see results. I prefer to screw it in until I find the engine smoothing out and then back it out and go in again, just to make sure it's in the right place. Tighten lock nut.

You really only want it screwed in as far as you need to stop the wild side to side rocking. Once that stops screwing it in further is not going to make it smoother. These engnies shake and that's all there is too it. If it's screwed in too far it will mostly likely stall and be difficult to start.

Dan Penoff
Marshall Booth
Richard Sexton