Hydraulic cooler

Our problems with 300 were progressive as well as two fold. when dad bought the 300, dealer installed the 31 loader from the H. Cylinders on the 31 loader had return line thus hydraulic oil supply was adequate. A year later dad traded loader for a 33A with hydraulic bucket and single action cylinders on the lift. Problem with this was, 300 would run out of hydraulic oil before loader was all the way up. Dealer changed lift cylinders to double action. It worked better but resovoir had to be right full, plus running as many as 5 manure spreaders from one loader tractor, the heat factor was a problem. You could get nasty burn marks on your arms reaching into tool box if you happened to touch hydraulic lines. Not serious burns by any means but they were uncomfortable.

After installing the added resovoir, it improved both problems. This was part of an evolution, none of that series of tractors had enough resovoir for hydraulics;100, 200, 300 or 400. Was fine if it was nothing more than rockshafts on the 100 and 200 or a single implement cylinder on a 300 or 400. Farmers were however starting to use hydraulics a lot. Lets face it 100 and 200 had an 8 pint hydraulic resovoir, that included pump and lines. I don't have the figures for 300 and 400, but as I recall not a lot more than 10 quarts. You add a loader to that with double action and hydraulic bucket, more than 50% of your hydraulic oil will be in loader at any given time. The system will now have 20 quarts.

By 1958 we started seeing transmission and rear end as hydraulic resovoir. Lets face we had come from a quite simple belly pump in early 50s. Before the decade was over we were pumping twice the presure and twice the gpm, and trying to do it with little more oil. Just part of the engineering evolution, we now know how to correct it, "MORE OIL", doesn't matter whether it be added cooler or resovoir, both give more oil.

Farmall 300 hydraulic systems run very hot. My experience is going to a new 300 in 1955. My dad, brothers and I had more burn marks on our skin than I care to remember. The system has a relatively small resovoir.

The IH dealer at the time helped our tractor a lot by installing extra resovoir. Tractor had a 33 loader, thus they installed a 5 gallon cylinder type resovoir across top on loader sub frame. They ran hoses from both drain and fill plug on 300 resovoir. The breather then must be removed from under hood and placed on top of add on resovoir. This extra resovoir also helped another problem, gave added hydraulic oil when using multipul cylinders. That added resovoir must be high enough so oil can flow to hydraulic system by graviety. The two hoses allow that oil to circulate much like thermosyphon.

SOP with hydraulic coolers is to place the cooler in the pump suction line (~0 psi all the time!) or to stick a cooling loop in the hydraulic reservoir and pass engine coolant drawn from the bottom of the radiator thru it.

However adding a cooler to your 300 is only treating the symptom! The better approach is to determine and correct the root cause for the hydraulic system becoming hot. It sounds like there’s plumbing error, a priority valve hanging up, etc causing the pump relief to continually bypass oil. Otherwise a healthy hydraulic system on a 300 should run no hotter than about 120 deg or so. ...Bob M

Bob

An automotive cooler would bge a little enimic, I would think. Although the tranny pressures will run up to around 120psi (in reverse) the lube circuit and cooler pressure is only running at a mere 7lbs; a bit on the low side. Plus the fact that these coolers would be very restrictive in a hydraulic system.

What makes you think it is running overly hot? Normal temps should easily be up there around 200 to 300 degrees, I would think.

Allan

As I said the test procedure showed that the pressure was dropping when load was removed so it would seem it is working correctly. Before I ran the test, I was confident that I would find that the pressure would not drop and that would explain the heat build up - (the cast parts of the reservoir/valves have the paint blistered off in places so I know it was too hot!) The only thing I found that was amiss in the system was that the resevoir vent had been replaced with a greae zerk! So I know the system wasn't venting through the 1/8" pipe. Could that be a reason for overheating? Thanks again for your help. For Bob Frey, I only solved part of the leak problems so far. Watch out for those gaiter springs - they're tough to deal with.