First i'm very happy with the PTO setup on my 154's. I wouldn't change to anything else but to a bigger farmall super A to get a heavier duty PTO setup with more HP. These smaller cubs wether its a fcub or int154 cub lack the pto horse power.
Now with a hydraulic driven PTO or any heavy working hydraulic system the heat build up is a big problem. If we look at the highway mowers with those big hydraulic oil tanks on the sides of the tractors with the hydraulic driven lift arms and flail mowers with the constant drive can create a lot of heat in the hydraulic oil. We need to think about the flash point of the hydraulic oil and have away to keep it cool too. Having more volumne(gallons of oil) is the key to cool it. Sometimes we used a heat exchanger on the systems we tested too so the temps were kept at a safe level. If your going to design a hydraulic system we need a normal operating temperture range so we don't get too close to the flash point of the oil. If its not said or printed on the bucket of hydraulic oil the manufacturer can tell you this. We must remember that the heat is the biggest cause of hydraulic failure. I've had a home built logsplitter last for well over 25+ years because i put the right size oil tank on it matched to the hydraulic pumps GPM. In a constant working hydraulic system its a ratio of 1 gallon of hydraulic oil to 1 gpm of the pump.
Example; If you have a hydraulic pump with a 10 GPM (gallons per minute) this means the pump is moving 10 gallons of hydraulic oil per minute thru the hydraulic system building up heat. We need at least a 10 gallon oil tank. This is in a 100% of the time, hydraulic running/operation use. A front loader requires less oil because its not lifting or moving all the time so there is less heat when the oil is just flowing freely thru the system. As to where a constant hydraulic driven mower that runs 100% of the time creates more heat.
Now a Hydraulic driven PTO is a great idea just keep in mind we need a larger oil tank to match the pump. The tranny in the int154 isn't big enough.
Now when i design a hydraulic system i only consider the oil tank capacity vs the hydraulic pump GPM i never figure in the amount of oil thats in the system other than the oil tank. The extra amount of oil in the hydraulic hoses, the cylinders and control valves gives me a little more of a safety factor rather than have the 10gpm pump matched just to a 10gallon oil tank. We can have an extra 3 gallons of hydraulic oil in the system.(example) Again thats a safety factor. I sleep much better when my systems are designed this way and i know its safe. We need to consider the 90 to 100 degree days of operation too. This extra oil in the system covers it.
Remember when the hydraulic systems are run hot and over heated for long periods of time the seals/o-rings fail. To me the biggest thing in hydraulic 101 is heat, how to prevent it or how to get rid of it.
Now on my int154 FEL & backhoe project i'm thinking of using the take-off pullies on the drive shaft near the engine to correct the speed of 3,600 rpm for the hydraulic pump for the loaders. Its only 1,000 rpm now. I figure a 6 to 8 GPM pump with an 8 gallon oil tank. Having a screen on the suction line in the oil tank plus a filter on the return line will keep the oil system clean. Go to www.surpluscenter.com
and look at the hydraulic stuff(parts to build a system) if your still interested.
I'm hoping to finish my FEL/Backhoe project this summer and starting on it as soon as we get some warmer days. I just received the 1/2'' steel tubing and some of the parker fittings. I'm going to use 1/2'' steel tubing with bulkhead fittings so i'll only use shorter hydraulic hoses to the cyliners and control valves. It looks much neater that way too, plus the shorter hoses are cheaper and easier to store inhouse too.