I have a 1949 TO-20, which I am going to have restored this winter. Before I do that, I need to repair the hydraulic system. The problem I am having is that when a piece of equipment is raised, it takes a long time for it to lower when the control lever is placed in the “down” position. I read your excellent article in the January 2013 issue about trouble shooting the Ferguson hydraulic system, but could not determine if any of the repairs you suggested would solve my problem. Can you provide any information on how I might approach this problem? September 26, 2014
There are a few of possibilities as to what is causing the problem. I would wonder about the condition of the oil. Is it the right weight and type and does it have something in it that is making it difficult to flow through the valves and ports? The oil originally specified for this tractor is 90 wt mineral oil. You can purchase this oil in 2 gallon jugs from Tractor Supply or TSC, SKU # 0806600. The jug is labeled Traveler All Mineral SAE 90 Ford Tractor Transmission Fluid.” It will take about 3 jugs to refill the transmission, rear axle. You pour it in at the transmission cover plug and it will flow to the rear axle housing.
Is there some sort of blockage in the supply tube, lift cylinder or valve that is preventing the oil from flowing as it should? There is a tube that runs from the hydraulic pump to the lift cylinder. After draining the oil you can flush this tube if you remove the 3/8″ hex pipe plug at the right side of the lift cover and the plug which is really a bolt at the right front corner of the hydraulic pump base. The plug or bolt projects from under the center housing at an angle. Flush the tube with fuel oil or mineral spirits and use compressed air to clean it out. Then reinstall the plug/bolt and flush the line back to the valve the same way. The solvent will drain out the bottom of the center axle housing.
There are multiple plugs that have to be drained to empty the entire system. There is one under the transmission, one in the hydraulic pump base and one under the differential. If there is blockage in these areas it is likely the cases have debris in them and should be flushed with fuel oil or mineral spirits as well.
Is your control lever properly adjusted. Adjustment of the control is covered in the article you referred to. It is likely dirt or debris is plugging the passages but I would check to make sure the Ferguson System is properly adjusted before draining the oil. After the system is flushed and the oil replaced with new oil, I would again check the adjustment. If none of these solutions work you need to remove the pump and inspect the valve.
It is possible there is damage to the valve or residue causing it to stick in the bore of the sleeve it slides in and out of. It is also possible for the sleeve to move and obstruct the flow. There is more information about this in the shop manual.