Starter issue - flywheel?
 

I'm hoping one of you might have some insight. I have a 1982 240D with a manual transmission that has been giving me issues for the better part of a year and I need to get it ready for this spring.

I had the starter rebuilt after some intermittent issues with the starter getting stuck upon ignition. It got progressively worse, and I suspected a rebuild would solve the problem.

After I installed the rebuilt starter, the ignition turned the starter. I have been having some air-in-the-fuel issues, so I worked to diagnose these. Within the first couple of startups, the starter no longer turned the flywheel (turned ignition, no sound, checked continuity to both sides of the solenoid and everything looked good).

I thought it might be the starter, so I pulled it out again (and bandaged my knuckles again). I bench tested the starter with jumpers and the solenoid clicked and the starter whirled. I put it back in. During the first startup it cranked like normal to start and then it made an empty sound (as though spinning without resistance). Now it won't crank at all.

I thought it might have to do with the flywheel, so I cranked the driveshaft by hand. Still nothing.

Any ideas? I am desperate - I am to the point I would take it to a shop if I could get it there without a tow. When I am pondering a garage, I know I'm getting desperate...

Dont know if this could relate to your problem but I once bought a cheep 240D that supposedly only needed a starter. Turned out the ring gear was slipping around the flywheel. I could move the ring gear with a big screwdriver through the starter hole. I had a good F/F so I just swapped them out, but it was a lot more work than just replacing the starter.

What would cause the ring gear to slip? Besides the air in the fuel line issue which has been difficult to track down, it was running fine.

Beats me, thats the first time I ran across that. Its not welded to the f/w.

You may still be dealing with marginal starter. I would probably source a cheap one from a pick and pull and substitute what you have first.

Teeth destroyed would be about it. In your case it sounds like the solinoid did not drive the bendix drive into the flywheel ring so you just heard the starter spinning under no load.

The lose ring gear is a long shot but easy to check when you pull the starter again. You can get some good leverage with a big screw driver in the starter hole.

Most ring gears on flywheels are not welded on.
They are heated up evenly such as putting it in an oven and baking it while the flywheel it self is at room temp.
When the ring gear hits a certain temp at a certain time thenit is ready to be installed on the flywheel.
let evrything cool for a day then install it on the engine.\
The reason for the slipage of the ring gear is either the ring is worn or the flywheel wasnt macjind right from the getgo.