Author Topic: After Market Starter Motor won't mesh with flywheel (Read 12919 times)

jasonsansfleece · « **on:** March 21, 2009, 04:03:51 pm »

We have a 1999.5 Jetta TDI (A4) We just bought it. The starter motor was gone, we replaced with an aftermarket one from Auto Zone. The copper wire from the solenoid to the original starter had failed, so we decided to just go ahead and replace the whole thing.

The trouble with the new motor is that it won't engage properly with the flywheel. Sometimes it will, but more often not. It seems worse when it is cold. The gear on the starter motor throws out correctly when tested out of the vehicle, but when in the vehicle the gear collides with the flywheel gear and you can see the damage just on the tips of the starter motor gear as a result.

The gear on the flywheel looks to be in good condition except for shiny marks where the new starter motor has been hitting it and in fact now has produced a slight burr.

Also the new starter motor does not have the extended shaft which rides in the bushing opposite. We don't think that the old motor had the extended shaft, either, because the bushing looks black as if there has been no wear.

We took the starter motor back to Auto Zone and compared it with another remanufactured motor of exactly the same type. It looks identical. Gear looks identical. I imagine putting another motor of the same type in would give the same results.

The question is, what is one to do?

Is it possible to put a "lead" on the starter motor gear to assist with meshing?

Should the starter motor be shimmed? Like one might a Chevy? (I doubt it)

Any suggestions or tricks to get this to work would be much appreciated.

Car is a daily driver and is now off the road.

thanks!

Guy and Lizzie

jtanguay · « **Reply #1 on:** March 21, 2009, 05:01:57 pm »

maybe the starter bushing (in transmission) is worn out?

jasonsansfleece · « **Reply #2 on:** March 21, 2009, 07:50:14 pm »

The starter motor does not have a shaft that fits into the starter bushing.
Nor did the starter motor that I took out.
Because neither motor was OEM?
The old motor meshed fine, the new one does not.
Is there a "tweak" to get this thing going, or do I demand my money back and try a different supply? the stealership perhaps?!?

the caveman · « **Reply #3 on:** March 22, 2009, 07:55:10 am »

Just so you don't think the starters are wrong, the newer style ones are self supporting -i.e. they don't need the bushing in the transmission.
If you match up the ends of the 2 starters, are they the same depth ?

jasonsansfleece · « **Reply #4 on:** March 22, 2009, 09:17:02 am »

Thanks for the word on the self supporting starters.
The original motor has already been returned so I cant compare.
Examining the the gear on the motor I can see that it has been able to fully engage with the fly wheel but more often it has not.
I can see tips of the gear worn where its trying to engage but is unsucsesful and jumps out and rides the edge of the flywheel gear.
The parts store says there is nothing wrong with their motor, that its my flywheel.
Should I attempt to shim it? Or try a different motor?

the caveman · « **Reply #5 on:** March 22, 2009, 09:31:14 am »

Since there probably isn't [but not impossible ] that's there's nothing wrong with your flywheel, we can assume it's the starter or related to it. But just to be sure, was the engine turning before all this even slowly ? Are you sure it's not seized. Can it be turned by hand? If all that is okay ,the other thing is making sure the starter goes in square. Don't tighten on bolt all the way and then the other. Torque them down evenly. Next get a jumper cable and go from the negative of your battery to the engine block. That will negate any issues with a bad ground. If that doesn't do it, disconnect the small wire from the ignition switch and go direct to the battery with a medium gauge wire by hand. This will negate any switch/ fuse box issue. If after all that it's the replacement starter. See if you can't borrow a good used perhaps to try??

jasonsansfleece · « **Reply #6 on:** March 22, 2009, 11:20:37 am »

Thanks Caveman
The engine starts as It should as long as the starter engages.
The original motor was replaced for the reasons outlined in the first post.I wish I had rebuilt it!
I had installed as you discribed, cleaned the mating surfaces between the housing and the motor. Tourqued to the specs given in the Bently.Ive serviced all the cables and their connections and current flows as shown when the motor does engage and it cranks strongly.
As far as I can figure, its either misalignment (how?)
Incorect gear shape/section.
Some function of the soleniod.
Tell me, does the solenoid push the gear out or is it centrifugal force?

burn_your_money · « **Reply #7 on:** March 22, 2009, 01:25:26 pm »

It sounds like you need to get a different starter.

jtanguay · « **Reply #8 on:** March 22, 2009, 02:45:49 pm »

Quote from: "jasonsansfleece"

Thanks Caveman
The engine starts as It should as long as the starter engages.
The original motor was replaced for the reasons outlined in the first post.I wish I had rebuilt it!
I had installed as you discribed, cleaned the mating surfaces between the housing and the motor. Tourqued to the specs given in the Bently.Ive serviced all the cables and their connections and current flows as shown when the motor does engage and it cranks strongly.
As far as I can figure, its either misalignment (how?)
Incorect gear shape/section.
Some function of the soleniod.
Tell me, does the solenoid push the gear out or is it centrifugal force?

theres a spring that holds the solenoid in. the solenoid pulls on a lever that shoots the sprocket out to engage.

i think you should remove the starter and examine the flywheel while rotating the engine by hand. just to rule it out.

it could also be that the starter isn't getting enough juice.

Dakotakid · « **Reply #9 on:** March 22, 2009, 03:13:05 pm »

Just out of curiosity, why oh why did VW go with self-supporting starter types?

Are they used elsewhere (commonly) in industry these days??? It seems as though when they get to the end of their service life that they would have a tendency to "take" flywheels right along with themselves.

rallydiesel · « **Reply #10 on:** March 22, 2009, 06:52:44 pm »

Maybe the flywheel ring gear teeth have slightly bent over over years of use to the point the new starter gear won't mesh perfectly. The old starter gear would have worn along with the ring gear so they would have been matched.

jasonsansfleece · « **Reply #11 on:** March 23, 2009, 09:30:50 am »

Rallydiesel, you may well be right. such wear is not apparent but could be the case.
And if thats so, do I need another fly wheel!
Is it possible to grind/file a lead on the motor gear.
The new fly wheel option is not really an option.
Parking on hills,
Guy

rallydiesel · « **Reply #12 on:** March 23, 2009, 11:40:09 am »

For some reason I thought you had an old Rabbit. I don't think your car has seen enough miles to have much ring gear wear.

burn_your_money · « **Reply #13 on:** March 24, 2009, 09:52:43 am »

Try physically turning the motor over 1/4-1/2 a turn (crank) and see if the starter meshes ok. Many engines always stop in the same position and that area of the flywheel might be worn

diesel smoke · « **Reply #14 on:** March 28, 2009, 07:47:34 pm »

Lets back up a bit. Since VW changed chassis mid '99, is it possible that the trans/starter/bell housing is different and they gave you one for a '99 not '99.5? I do know that VW used the ALH engine in '98, so I could be wrong. I know that if I get parts from just some regular auto parts shop, I sometimes tell them to get parts for a '00, so I know it is right.