[Farmall] O-12 flywheel

Karl Olmstead olmstead at ridgenet.net
Fri Nov 25 20:07:49 PST 2005


I finally pulled the last tractor out of my shop and parked it in my new 
storage building.  So there's lots of room in the shop to work on tractors.

First project is an O-12 that's already in halfway decent shape.  Engine is 
not stuck, and it even has some compression.  But I'm still going to pull 
the engine, put it on a stand, and check it out.

The O-12 is a considerably different beast from the F-12.  It has a full 
frame instead of two C-channels to hold the front and rear of the tractor 
together.  Instead of the wide open area behind the clutch, O-12's clutch 
housing is a large casting which connects engine to transmission.

I split the tractor today, and ran into a problem that I'm still having a 
tough time believing. The clutch housing unbolts from the transmission, so I 
wound up with the engine, front frame and clutch housing as one half of the 
tractor, the transaxle as the other half.  Quite straightforward.

Removed the clutch pressure plate and clutch, then pressed the flywheel off 
the crankshaft using the two 1/2" threaded holes provided for that purpose. 
Then I tried to remove the flywheel from the clutch housing.  And tried, and 
tried and tried....

It appears that the flywheel is 'captive' inside the clutch housing.  The 
opening at the top (normally covered by the steering gearbox) is at least 
half an inch narrower than the flywheel, so the flywheel can't be lifted up 
and out.  And the two bushings cast into the clutch housing in which the 
clutch shaft turns stick out so far into the interior of the clutch housing 
that the flywheel can't come out the rear opening where the transmission 
used to be.

This has some serious ramifications, because the engine is bolted to the 
clutch housing from inside, and two of the bolts are hiding behind the 
flywheel.  I finally got them loose, working one-handed in the little gap 
between the back of the engine and the front of the flywheel.

When everything is cleaned up and primed, I'll have to remember that I need 
to put the loose flywheel into the clutch housing before I lower the engine 
back into the front frame.  What an awkward setup!  This is one of the 
dumbest designs I've found in IHC equipment; it looks like something John 
Deere Company would have done.

Other than that, I'm having fun.  70 degree weather, a wide open shop, and 
an O-12 to rebuild.... who could ask for more?

-Karl 





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