Author Topic: Starter bendix hitting flexplate ring gear instead of meshing properly  (Read 2263 times)

Boxelder

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A question for the gear heads and mechanical thinkers:

I have a Mahindra 4505 tractor, basically an Indian-made IH B414.  It's been an excellent little tractor, but it has this one quirk.  When I go to start it, 9 times out of 10 the bendix just goes "clank" and hits the ring gear without engaging.  I keep on trying until it finally meshes and starts.  It's done this since I've owned it, which is an embarrassingly long time.  As one does, you just adapt your behavior to the quirks of your tools and get on with it.

A few days ago I finally attempted to address the issue.  I removed the starter and had a look.  Sure enough, it appears that the bevels have been improperly ground on the bendix.  Now I'd like to remove it and re-grind the faces.  Any suggestions on angles and depths, if it's agreed that this might be the problem?

Have a look and let me know what you think.

Thanks in advance!

ajaffa1

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Hi Boxelder, i don`t see anything wrong with the gear on the bendix, what I do see is a very flat face on the gear on the flywheel. I don`t know what could be done about it without enormous effort. You could perhaps try to grind a bit of a chamfer using a die grinder or Dremel. If you do try it please flush the grindings out before running it.

Bob

Boxelder

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Thanks Bob.  I'll check out some videos of flex plate ring gears to see what they're supposed to look like.

Boxelder

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Well I looked at hundreds of pictures of starter ring gears using google image search.

Some are beveled, but most are not.  This has always confused me just a little bit, as it seems like this type of issue would be more common.  I have to be missing something easy.

ajaffa1

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Hi Boxelder, just a thought but have you checked the alignment? If the starter motor is too close to the crankshaft it could hit on the face of the gearwheel rather than meshing with it. Does the starter motor have a locating ring on it? If not you could try elongating the bolt holes and let it ride a bit further away from the crank shaft.

Bob

Boxelder

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I did try to move it out away as far as possible when remounting it, to no effect. Will put some thought into your suggestion. Thanks.

ronmar

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I have never seen a bendix that didnt come to a near point.(rounded).  It looks like they ground one side, and the tip/outer edge, but not the other side.  I would take a die grinder and match the same angle on the un-ground side. 

They also left sharp edges.  I would also use a rotary file bit in the die grinder and round off all the edges where the angles meet. When it does come in contact with the side of a ring gear tooth, there should be no sharp edges to dig in as it slides off of the side of the ring gear tooth and engages,

Sharp edges here are like the sharp edges on the rotary file bit that dig in and remove metal...

Also check inside the solenoid for free travel and that it is pushing the bendix ALL the way forward for full engagement with the ring gear.  My chinese starter on my Jinma was lubricated with “Yak Fat” and did not like to move well when cold...
PS 6/1 - ST-5.

Boxelder

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Thanks ronmar.  I agree.  I sent those pictures off to the Mahindra dealer here in Atlanta, but he must be a bit behind on the emails because it took nearly a week for him to send me an email address where I could attach photos.  The contact form on their website had no such provision.

I'll let you all know what diagnosis they respond with.

cobbadog

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ronmar touched on the two things that i feel I would do. Grind the opposite side of the teeth on the bendix and clean up all edges so they are smooth. But I think your main problem is the starter itself. Ensure that the bendix does move freely and that the solenoid is in good condition and the contacts are very clean make make a good contact when they hit together. Also check your voltage to the starter. You may have a voltage leak in the system.
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