Bendix Retainer Collar

[sturmtyger380]

I am working my way though repairing and restoring my M37. I am taking everything off the engine to get ready to pull it.

The generator and starter were working fine so I decided to just clean them up and not try to mess with them. Well the Bendix on the starter has gone bad. It is frozen and won't free wheel in the opposite direction. That normally allows the flywheel to over run the starter speed and not damage the flywheel or starter gear.

I have gotten down to the collar that goes on the end of the armature. That collar keeps you from pulling the armature out of the Bendix. Inside that collar is a small snap ring that has a little groove where you can poke a tool in there to spread it open inside the collar.

I have tired to open that snap ring and just can't seem to get it to spread. Has anyone else been able to get that snap ring open and get that collar off?

What kind of tool did you use? Need help it's driving me nuts!

[j mccormick]

Tap on the collar to get it off the snap ring, remove the snap ring and the collar, and the bendix. Replace the bendix put the collar on, then the snap ring in the groove, then snap the collar over the snap ring using the bendix turning backwards to push against the collar. Probably clear as mud but that's the way I do it.

[sturmtyger380]

Oh, having not done this before I had no idea I could force the collar off of the snap ring. Now that you mention it that collar is there to stop the forward movement of the armature when you engage the bendix.

[sturmtyger380]

Well getting the collar off of the snap ring was easy. I took a socket a little larger than the snap ring and tapped the collar back. Getting the snap ring off was fun.

The insides look really dirty. I am thinking I need new brushes. Anyone know where to find replacement brushes especially the ones that are connected to the communicators?

[sturmtyger380]

Now the next issue. Now that the starter is separated I need to remove the field coils.

I decided to focus on one of these screws at a time that hold one of the coils on. I have heated that screw and soaked it for days with penetrating oil. I have broken an impact screwdriver bit on it.

Any clues as to how to get this screw and the others out?

I am about ready to weld a bolt to it!

[isaac_alaska]

iirc it's a flat head screw with a tapered head underneath? if you drill it out you should be able to remove the coils, put a vice grip on what's left of the screw, and then use new screws. usually the underside of the head is what siezes them in place rather than the actual threads.

kind of a last-ditch effort

[sturmtyger380]

Well everything else failed so on to the last ditch effort of drilling out the big slotted screws.

It worked out okay:



You have to be careful to drill enough to take off the pressure on the sides of the hole but not mess up the screw so you can't use a punch to get it to turn and come out:



Old and new end plates:



Old field coils:



How the post that goes from the power in to the field coil is expanded:

[isaac_alaska]

glad that worked for you!

[sturmtyger380]

I took the body of the starter and gave it a blast in the blasting cabinet as well as the field coil retaining shoes.

Then gave it a coat of varnish for elec devices. It is starting to look good.





Here is the spray. I used a brush on the end plate.



Now on to cleaning the armature.

[sturmtyger380]

I am just about ready to put the starter back together.

Last time getting the retainer collar off was the issue. Any hints on getting the snap ring on and then forcing the collar back over the snap ring?

[sturmtyger380]

Well that was not too hard. The retainer ring just slips over the shaft. The snap ring will slide down to where the shaft expands for the groove that holds the ring.

I used the same socket I used to force the collar off before but used it to force the snap ring into the groove.

The harder thing was to get the collar over the snap ring and keep the ring in the groove. I used a small two jaw puller to try and pull the collar over the snap ring but it has a tendency to want to push the snap ring back out of the groove.

I ended up using the two jaw puller to keep pressure on the snap ring as I tapped on the snap ring with a small screwdriver to force the ring to stay in the groove and go inside the collar as I tightened the puller after each tapping round.

Now the reassembly can go forward!

[sturmtyger380]

Well the first thing I ran into was the armature would not go back in the housing. The shoes for the field coils were out too far.

That's when I learned you need a field coil spreader to force the shoes into the coils and also get the coils to snug up to the housing. Well I don't have one so I went looking on the internet and made my own:



They worked okay and did spread them a good bit and I was able to tighten up the screws holding the shoes in. But the threads of bolts I were using wore out. Now the armature would go in but was dragging on the shoes. So I took my muffler pipe ex-pander tool and used it. First I headed the housing with the field coils over a kerosene heater to help make them playable.



Well that helped more but I still had to take a hand held grinder air tool and remove metal from the face of the shoes to allow the armature to spin without dragging. I got it back together and tested it and it spins fine. (I don't think most folks have to grind the metal.)



Now to put the switch and lever back on.

Alan

[isaac_alaska]

what was keeping the shoes from getting pulled up tight against the housing by the screws? i've taken a few similar motors apart before and never had a problem , the only difference i can think of is that the ones i worked on had two bolts per shoe instead of just 1, so they're guaranteed to be parallel to the axis of the housing.