1942 GPW Starter Issue

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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John Schroeder
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1942 GPW Starter Issue

Post by John Schroeder » Thu Sep 21, 2017 2:36 pm

I am in the middle of restoring an April 1942 Ford GPW. I have the usual slow cranking expected from an original 6 volt system but recently it only cranks about a half a stroke of the engine and the front plate on the starter (the end closest to the front of the engine block) gets hot after 3-4 cranking attempts. Hot enough that you can hardly touch it. The engine is recently rebuilt but I had it running a few weeks ago and put 3-4 miles on in a road test. The battery is new and the volt meter on the battery charger shows 100% charged.
Thank you
John
John Schroeder
1942 Ford GPW
1944 VW Type 82 Kubelwagen
1944 Cushman Type 53 Airborne Scooter
1944 John Wood M3A4 Hand Cart
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dpcd67
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Re: 1942 GPW Starter Issue

Post by dpcd67 » Thu Sep 21, 2017 3:37 pm

It shouldn't be that slow; check your timing. Advanced timing will cause that. As will poor grounds, low batteries, bad starter, and holding your mouth wrong. Six volt systems have to be perfect to work well, whereas 12 volts gives a lot of room for error.
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Re: 1942 GPW Starter Issue

Post by artificer » Thu Sep 21, 2017 3:58 pm

John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: 1942 GPW Starter Issue

Post by conrod6 » Thu Sep 21, 2017 9:38 pm

That little angled support bracket on the commutator end of the starter is a major earth connection - so make sure it is scraped clean and is tight - no paint under the connecting surfaces.

Barrie
GPW 101005 DOD 3-2-43 20207773 (actual) Louisville

John Schroeder
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Re: 1942 GPW Starter Issue

Post by John Schroeder » Tue Sep 26, 2017 4:39 am

All, what would cause the commutator end of the starter to be extremely hot after just a few attempted cranks on the starting motor?

Thank you

John
John Schroeder
1942 Ford GPW
1944 VW Type 82 Kubelwagen
1944 Cushman Type 53 Airborne Scooter
1944 John Wood M3A4 Hand Cart
1945 Ben Hur Water Trailer

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Re: 1942 GPW Starter Issue

Post by conrod6 » Tue Sep 26, 2017 7:36 am

Its caused by a heavy current being drawn by the starter from the battery - any real hotspots will be caused by a poor connection as indicated in the responses above.

Barrie
GPW 101005 DOD 3-2-43 20207773 (actual) Louisville

John Schroeder
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Re: 1942 GPW Starter Issue

Post by John Schroeder » Tue Sep 26, 2017 7:41 am

So it is normal for the front end of the starter to be very hot during operations?
Thanks
John
John Schroeder
1942 Ford GPW
1944 VW Type 82 Kubelwagen
1944 Cushman Type 53 Airborne Scooter
1944 John Wood M3A4 Hand Cart
1945 Ben Hur Water Trailer

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Re: 1942 GPW Starter Issue

Post by conrod6 » Tue Sep 26, 2017 10:15 am

Hello John the motor will warm up with use - the longer it runs the warmer it will get. If you cannot touch the commutator end cap after a short time struggling to start the engine I would take the unit off and take a look inside. Two of the brushes are connected straight to the end cap and earth the motor through the small support bracket to the engine block .The other two brushes are connected to the cable terminal via the field windings. This particular motor type does not have its primary earth through the casing at the bell housing .

Barrie
GPW 101005 DOD 3-2-43 20207773 (actual) Louisville

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Chuck Lutz
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Re: 1942 GPW Starter Issue

Post by Chuck Lutz » Tue Sep 26, 2017 11:11 am

Just to add to this....you DO have the ground cable that attaches to the "L" bracket that is bolted to the block that holds the commutator head flange, right? Clean off the paint where the strap is attached, use the grease as noted above and toothed washers as per the manual and check all the fittings on the ground cable back to the frame. Then check the battery ground cable-to-frame (or battery tray) for clean, tight, paint free fitting.
Chuck Lutz

GPW 17963 4/24/42 Chester, PA. USA 20113473 (USA est./Tom W.)
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Re: 1942 GPW Starter Issue

Post by artificer » Tue Sep 26, 2017 4:39 pm

OK....
Most starter issues as you have indicated relate to a dirty commutator most commonly caused by over lubing or poor brush contract.

A good cleanup ensuring all parts are fitted to the armature shaft is essential before re-assembly.

Do not undercut the armature & if this has been incorrectly done previously ensure the commutator groove areas have all brush residue removed. JG
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

John Schroeder
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Re: 1942 GPW Starter Issue

Post by John Schroeder » Tue Sep 26, 2017 6:27 pm

All, great advice. I cleaned up all the grounding areas suggested and replaced the end of the starter. It cranks over much quicker now and I was able to get it started today. All I have to do now is re-bleed the brakes and it should be road worthy. Stopping is as good as starting.
Thanks again for the advice
John
John Schroeder
1942 Ford GPW
1944 VW Type 82 Kubelwagen
1944 Cushman Type 53 Airborne Scooter
1944 John Wood M3A4 Hand Cart
1945 Ben Hur Water Trailer

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Re: 1942 GPW Starter Issue

Post by artificer » Wed Sep 27, 2017 12:46 am

For reasons given I don't recommend pump bleeding....http://jeepdraw.com/images/HOW%20to%20B ... LEEDER.pdf
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

John Schroeder
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Posts: 143
Joined: Thu Jun 26, 2003 4:54 am
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Re: 1942 GPW Starter Issue

Post by John Schroeder » Wed Sep 27, 2017 4:47 am

For some reason vacuum bleeding is not working. I can maintain about 15 inches of mercury of vacuum at the bleeder screw but I am not drawing any fluid through the line. I am using a rebuilt master cylinder, all new wheel cylinders, and I blew out the lines before reassembly. Not sure, but I think I am getting vacuum created in the lines somewhere preventing the flow of fluid from the MC to the wheels.
John
John Schroeder
1942 Ford GPW
1944 VW Type 82 Kubelwagen
1944 Cushman Type 53 Airborne Scooter
1944 John Wood M3A4 Hand Cart
1945 Ben Hur Water Trailer

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Re: 1942 GPW Starter Issue

Post by artificer » Wed Sep 27, 2017 11:26 am

Hard to pull a vacuum if air is leaking in around the bleeder's threads. A run of thick paint around the external area to stop an air leak when the bleeder is loose. The little mytvac units don't cope well. All new & you can use pump method but make sure the pedal does not go right to the floor....use a block of wood to stop full pedal travel.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.


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