Originally Posted by sixto

I bought a Baum brand ring gear tool, the kind that slips in place of the starter to keep the crank from turning. It was immediately disappointing to see that the locking cogs were cut from an MB ring gear. No problem if it was a cheap tool but this one fetches three digits. The bigger problem was that it didn't fit. The bridge has two pins which are a very close fit in the starter bolt holes. The pins weren't quite parallel (or my block is out of spec ). Minor prying got the pins aligned. So I inserted the tool but it wouldn't engage the ring gear. Looks like the cogs were welded to the bridge about 2.5mm too close to the crank axis. Not wanting to wait out a warranty claim I punched out a pin and put an 8mm hex key in its place. The smaller effective diameter of the hex key set the cogs back enough to where they engaged the ring gear. Worked like a charm.
To those who've replaced the front crank seal with the engine in the car, how did you keep the crank from turning if you didn't use this tool?
Sixto - 93 300SD