DC3 Starter Motor broke

Paul f · Jun 18, 2014

DC made a really loud noise on start up today but started an ran. Shut her off after moving some round bales then she would notcrank. Ammeter showed max draw but no sound. Pulled the starter motor and the nose cone had snapped off. The tapered set screw was in place and tight so I am not sure why the cast iron housing decided to snap...any thoughts????

Christopher Mikesell · Jun 18, 2014

This is what happens when the bushing at the tip of the cast iron housing gets too loose. The gear on the flywheel jams against the pinion on the starter and it breaks the housing. This is caused by excessive center distance between the two gears. It is a common problem with old tractors. Really, that bushing should be replaced whenever the ring gear is replaced.

John Saeli · Jun 18, 2014

Burred teeth on the Bendix & Ring Gear will also do it. Makes the gear want to climb & bind. 35 years ago, when I was a kid, the cone broke on my DC starter. I welded it back, still holding today, but my Uncle told me to file the burred teeth, or it would do it again. I filed them & it hasn't happened since.

mEl · Jun 19, 2014

John.

On our big cube high compression DC puller we broke a couple of cones, finally we welded a pad of weld on the outside of the cone just above the rear bushing that would contact the bell housing and then ground that pad down just so the set bolt would seat, no more problems other than enough starter to turn it.

mEl.

Paul f · Jun 19, 2014

Engines tend to stop at the same spot. On my VAC the ring gear looks good except for a couple of inches at one spot. (also another wear point 180 degrees off that)Had to file those points a bit as that starter would hang up....Guess I better take a close look at the DC to find the wear points and get filing....

Welding cast iron is probably beyond my ability anyone have a rebuild-able core???...This starter was rebuilt about 3 years ago so the armature field coils are all good and I could reuse them.

mEl · Jun 19, 2014

Paul,

We repaired our with a mig and stainless wire, a good cherry preheat then weld, keep heat on and gradually cool it. We broke and welded that cone 3 times and it broke in different spots each time, each removed from the old welds.

mEl

Paul f · Jun 19, 2014

Mel did you remove the starter motor innards before you welded???

mEl · Jun 19, 2014

yes, completely disassembled, vee'd it out. we held it together I believe with a long bolt and plate to keep it in alignment.

Don't be afraid to disassmble the starter, the toughest part is getting the brushes back in place and I simply remove them from their holders and assemble, then use a 90 degree oring pick to lift the springs to slip the brushes in place. I use a small bit of rtv to replace the gasket at the intermediate bearing plate.

Paul f · Jun 20, 2014

I appreciate the info you have provided. Thank you. One more question, did you v and weld both the outside and inside or just the outside. The way mine has broken working on the inner surface looks much more difficult.

Thanks again!!

mEl · Jun 20, 2014

All from the outside, leave just enough to keep proper alignment.

DC3 Starter Motor broke

Paul f

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John Saeli

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mEl

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Paul f

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mEl

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Paul f

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Paul f

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