In Reply to: Re: Ford 8N tractor starter won't disengage, Positive Drive type posted by Brad on March 09, 2020 at 11:02:45:
There are noted to be several different designs of inertia starter Bendix, which causes a bit of consternation, because not all Bendix designs lock in the extended position like Ford 8N tractor starter Bendix do. "After I have learned the answers, they change the questions" ;-) Linked is video of Bendix that doesn't "lock open" on a vehicle. Nice as everything is out in the open and you can see how Bendix drive works.
On N Ford tractors "Locking open function" was an effort to improve conditions where the Bendix would try to disengage prematurely, before the engine was thoroughly running. Dell, Sound Guy, Hobo and others have commented on this topic on various repair forums, providing further information/explanations for those who want to search & know more details.
One helpful thing they've pointed out: you can put a starter back into an N series tractor with the drive extended (locked position), and when engine starts running, Bendix will retract from locked open position. They have further expounded that if drive pinion gets hung up on ring gear and Bendix won't let go, you can put the tractor in 4th gear and use big back wheels to rock tractor back and forth and sometimes it will get the Bendix to release from the ring gear, without resorting to starter removal. Nice shortcut, if it works.
Also shown on various forums: an angle grinder with a cup wheel spins Bendix fast enough on starter to unlock pawls so Bendix retracts. Good to know, not necessary to remove Bendix from starter then having to use screwdriver and wire brush with a bench grinder (method I've used before).