that would be my first thought, I'm getting ready to replace my Bendix as it stopped engaging the flywheel, so I spend my last weekend out with the car cranking by hand. I'm glad I can do it, but I don't want to if I can help it.
I had my first car when I was still at school so money was really tight. I reused the ring gear back then. In a motoir like the Model A, the ring gear will wear in two places, 180 degrees apart. BY turning it 90 degrees, you've gained many more miles out of it.Here is a guy that both replaces and shows how to rotate and re-use the worn ring gear.
https://www.youtube.com/watch?v=gCjdE56-LuQ
There are a couple of the same type videos available there.
I replaced one in my 239 flathead awhile back, removed old one with a punch and hammer. Placed flywheel in the freezer (Momma was out for a couple of hours). Then, not having a torch I got a good bed of coals glowing in the bar-b-cue, placed the new ring gear on the coals for about five minutes and it dropped right on the chilled flywheel. It didn't take long to heat and I was careful not to overhear it and mess up the integrity of the ring gear. Took a couple of tries, but when the temps were right, clink, it was on. There is a right way and a backwards way to put these on, so be sure you got it right the first time. Chap
CB919ER -
Are you certain that the teeth on the flywheel aren't worn down, hence the inability of the starter to engage the ring gear teeth and turn the flywheel? This is a very common problem with older flywheel ring gears that have had tens of thousands of starts on the teeth. What happens is a Model A engine tends to stop in one of two places 180 degrees apart most of the time. That means that the same area of teeth in those two places gets the majority of contact by the Bendix the next time the engine is started. After so many starts, the teeth in those two areas get worn down to the point that the Bendix can't engage them. Use the hand crank to rotate the flywheel a couple inches in its travel, and then try the starter again. This puts the Bendix in contact with healthier teeth that have had little or no use over the years. If this is successful in a couple different places around the ring gear, then you know it's the ring gear that needs replacing. Or you could just heat the gear and rotate it on the flywheel a couple of inches either way to put fresh teeth in those two starting areas, but that's a lot of work just to make a used ring gear serviceable. It would be better to install a new ring gear and be done with this problem for the rest of your lifetime - and probably the car's! Stake the new ring gear in place against the flywheel's stop ridge with countersunk Allen head bolts and you'll never have to worry about it walking forward, as some repo ring gears will do.
However, if trying different areas on the ring gear still fails to let the starter do its job, the Bendix spring or bolts may be broken. The sign of this is a high speed turning of the starter because there is no longer any resistance from the flywheel. You should notice a radically different sound as the starter spins freely and probably clanks a little.
Marshall
Grease on the spiral of Bendix will sometimes cause to it to not engage this problem is worse if cold weather.
Clean grease and use light oil like Three In One.