espotony
New member
I'm having problems with the hitch on a 1965 gas IH 424 with PS and FEL. Previously, the hitch was rock-solid. It would hold up a weight box loaded with stone indefinitely. Recently, without warning, it now hiccups - that is, it raises, then drops, then raises, continuously. Whenever it does this, the steering wheel also pulses. Previously, there was no issue with the steering. If the lift is raised, then the engine turned off and the isolator valve turned in, the hitch will drop the load in about 1 minute. If the engine is running and the isolator valve is closed, the pump begins to scream, so I feel that the isolator valve is working correctly. The full/half-speed valve on the left side also seems to work properly. I'm pretty good with engines but have no experience with hydraulics, so I bought the factory manual and hired a well-recommended mechanic who helped me with this. We removed the hitch and put a new seal on the piston. Neither the cylinder nor piston showed any signs of scoring. The filter in the lift housing was clean, but I flushed it anyway. The oil appeared normal-no water or signs of foaming. No broken parts or metal chips in the housing. Additionally, we replaced all the O-rings on the cylinder head, including the large one that seals the cylinder. I feel very comfortable that the work that was done was done correctly and well. After reassembly, there was no change to the hitch behavior. However, the FEL, which had previously needed engine revving to lift a load and would slowly drop the bucket after turning off the tractor, was a great deal more solid and would hold the bucket up for several hours. It would also lift a modest load with the engine at idle and would lift a heavy load effortlessly which was a great and unexpected improvement in its performance. So we disassembled the hitch and this time cleaned and/or checked the 4 valves in the cylinder head. All were cleaned and new O-rings installed. Nothing seemed worn or damaged with the spools or the relief valve. The draft piston showed signs of very light rubbing, but no scores or wear marks. Everything else looked like new, O-rings excepted, most of which had flattened edges and had gotten a bit hard. We also disassembled the little relief valve in the piston and I think, replaced an o-ring. The tiny check ball is certainly present. We used a compressor to blow out the passage and pretty much confirmed that it would only pass air in one direction. There doesn't seem to be any adjustment in the linkage for the draft and position valves. Everything with the linkage appeared normal-no bends, scores etc. We carefully reassembled, making sure that all the check balls and springs, etc were present and in their proper location, verified by comparison with the factory manual. Started it up and everything seemed A-OK, except that after turning off the engine, it would drop the load in about 5 minutes. As I mentioned, previously, the hitch was rock solid. Next day, all problems returned. A curious thing which I can't explain is that FEL which draws hydraulic oil from the differential housing is returning it to the lift housing. There doesn't appear to be any way for hydraulic oil to return to the differential. I should mention that the tractor has 2 hydraulic pumps, one for the FEL and a 2nd for the hitch and power steering. Both pumps seem to be OK, as both the hitch and the FEL will lift a load properly. The hitch just will not hold it up. I have owned this tractor for about 5 years but have been familiar with it since it was new. It did receive a new front pump about 10 years ago. For its age the tractor has seen modest use and has not been abused. Besides the pump, I don't think it has suffered any major problems and it has received regular maintenance. There is a large additional hydraulic oil filter on the right side of the engine which I have not yet changed/cleaned but after all this I'm skeptical that it is the problem. I'm flirting with the idea that the diverter valve in the power steering might be involved. This is a long post but I thought if I included every conceivable clue, it would be helpful. I and my mechanic are otherwise out of ideas. I sure hope one of you with experience can help. Thanks so much.
Tony
Tony
