M hydraulic question

Fred47M

Member
Well I had accepted that I would have to do something with the belly pump on my 47 M. but read a post about different tractors pressures and cylinder size. Anyways I put a loader on it, would only lift about 250lbs, and drop with lever with no resistance. I wasn't able to use original cylinders, badly rusted. The original IH 33 cylinders have a 1 3/8 rod in a 2 1/4in I.D bore. The replacements came off farmhand on I was told for WD45 1 3/8 rod and 1 7/8 O.D cylinder. Is that a significant of a difference to cause this. Engine does react when a try to lift more. First time I tried to use pump on this tractor. New hyd oil, plumbed separately, front ports Thanks
 
ASSUMING you mean the "new" cylinders have an I.D. of 1-7/8", the original cylinder pistons would have an area of 3.97" and the "new" cylinder pistons would have an area of 2.75", QUITE a difference.
 
The diameter difference makes radical lift difference. The M probably makes 750 to 850psi. with the leverage on the cylinder, and 60+ years of age, it is not going to lift much. If the Allis cylinders are 1-7/8 OD as stated. they are even smaller than usable at those pressures. Cylinder time. Surplus Center might be a source. Jim
 
Try 30 weight non detergent motor oil. Sold @ AutoZone. You might be surprised. I had a neighbor with an M and a wheel disc. He was complaining about how he could only lift the disc a little bit off the ground and the pump would whine. I asked him if he trusted me and he said yes. He bought 7 or 8 quarts of 30 wt. and we switched over and emptied the line and cylinder. The disc came off the ground like the pump was brand new. Good Luck, Ellis
 
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