John Deere ‘E’ Oil Leak Fix

By Staff
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160909 Carter Canyon Road, Gering, Nebraska 69341

Many early John Deere ‘E’ engines develop annoying oil
leaks around the magneto area. Also, most have some leakage of oil
around the mains. I have been able to solve or greatly reduce these
problems on several 1 HP and 3 HP engines and will pass on
information on the procedures I have used. I can’t guarantee
complete success, but I have been very happy with the results.

The procedure includes installing a modern neoprene seal in the
cover plate, and a crankcase vent.

I use seal #1-196-089 M1 purchased from my Massey Ferguson
dealer and machine both the cover plate and the magneto gear to fit
(see drawing). Both machine jobs are done on a small metal working
lathe. I center the plate using the existing hole for reference and
center the gear surface from the gear center hole using a mandrel
(also easily produced on the lathe).

A four jaw chuck gripping the toothed part of the gear could be
used, but there is a danger of breaking a gear tooth due to the odd
number of teeth. I prefer using a mandrel in the gear center hole.
Some gears have enough asymmetry in casting to cause the machined
flange to become somewhat thin, however, I believe most, if not
all, will finish satisfactorily.

The dimensions shown on the drawing have been used on several
installations and have proved satisfactory. A light press fit of
the seal to the plate is desired. Be sure to measure the seal
diameter before machining the plate and allow approximately
.002′ interference. Install the seal with the lip inward and
oil the rubbing surface of the gear before assembly to the
engine.

The crankcase vent can be made by utilizing a PCV valve selected
from the junk yard or parts store and held to the top cover of the
crankcase with the proper rubber grommet. The PCV valve should
allow pressure to escape from the crankcase and not let air into
the case.

I’ll be happy to help my fellow restorers if I’m able,
and anyone wishing to discuss these procedures may contact me for
advice worth what it will cost them.

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