farmall 400

binkiewiczj

New User
about two weeks ago I was baling with farmall 400 and nh268 baler. Two windrows to go and tractor started to shake violently. Towed it home, dropped the oil pan and crankshaft was broke in half. Does anybody have a clue as to how this could happen? I am currently rebuilding the lower end and would not like this to happen again. Thank you.
 
could be from lugging the engine down , metal fatigue , plus running a baler off the pto is not the smoothest thing going.
 
fastfarmall, negative, no vibration, the whole front end started shaking. Existing problems prior to breaking crank- #4 plug was always wet - oil - some play in fasthitch - fasthitch was from a 560 - some knocking noise when turning will baling. after pulling pistons noticed scarring on the the #2 & #3 pistons. Just thinking the ramming of the baler transferred through drive line to crankshaft. Not sure. Tractor is split, going to replace sleeves, pistons , rod bearings and mains, also replacing clutch since tractor is split. While I am here I just picked up some cub parts from late Uncle as well as a variety of farmall brochures/manuals ranging from hammermills mowing equip, loaders, forage, plowing and variety of tractors. Thank you again for the replies.
 
This is only the SECOND broken crankshaft in an M/SM/SM-TA/400/450 I've heard of in 60 years of being around FARMALL tractors.

Neighbor had an M that he had rebuilt back around 1960. Sent the head to a machine shop to be planed flat. Shop screwed up and took off 1/8 inch, .125". The bump in HP was impressive. Jump forward to about 1964 or '65, Guy was plowing across the creek from our other farm, still pulling 3-14 IH #8 plow. My old Boss was picking him up for lunch, had shut his pickup off to listen to the M purr, was thinking, "That's one Awesome sounding M.." And just like you pulled the plug on a radio or TV things went dead silent! Twisted the crank in two right next to the center main bearing.

I wouldn't worry too much about it happening again. Align bore/hone the main bearing bores in the block, magnaflux the replacement crankshaft & rods, and that 400 should run for another 60 years.
 
Ok,that turning, with power going thru it is tough on any tractor, usually it wears the live PTO splines real bad and will eventually strip them, but i was thinking of of the harmonic balancer [on a M they call it the fan pulley drive] but as long as your going to have it off, take a good look at that !
 
Back when I was grinding shafts, I had an M shaft That didn't act right while setting it up. I found it was badly cracked. It would have broken soon if it were still in the engine.
 
The crank broke in our SMTA back in the late 70s while plowing. Plowed with it most of the day before figured out what it was , only made noise in the really tough spots . Came up for fuel let it idle , listening for noise and saw the front crank pulley moving back and forth . It broke jagged just in front of the front main . All we did was put a used crank in it and farmed with it another 10 plus years. That old girl worked hard for 30 years and still gets called to duty at times .
 

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