Re: 300U hydrolics

Posted by dick on April 26, 2002 at 13:07:33 from (209.244.76.30):

In Reply to: 300U hydrolics posted by Steven Garrett on April 25, 2002 at 17:11:19:

Steven:

I'd have to agree with the others that you must have the wrong book for your tractor. The Farmall 300 and the International 300 Utility are not the same tractor, although they do have some common features, most notably the same engine. Quality manuals are available from Binder, and I'd recommend that you invest some money in at least the operator's manual, it will save you money in the long run. The parts and service manuals are also well worth having if you're going to do much work on the tractor yourself.

As far as the bleed-down problem is concerned, you could have a problem in the cylinder on the hitch. To check for this you can raise the lift and support it with something or other while you disconnect the hoses from the cylinder and plug the cylinder connections with pipe plugs. Remove whatever is supporting the hitch, and put something reasonably heavy on the hitch. If it bleeds down, the cylinder needs work; if not, the problem's elsewhere. In the interests of safety, I expect I'd better say PLEASE don't work on the hydraulic lines while the engine is running, and if you do try this test PLEASE remember to support the lift again before removing the pipe plugs from the cylinder connections.

If the problem isn't there, it's most likely in the control valve area. By themselves the control valves on the 300U (and probably the other tractors IH tractors of the mid-50s) weren't good positive-shutoff valves. They have a very close internal tolerance (originally something like 0.0004") between the high- and low-pressure portions of the valve, which was always going to leak some, and since these valves are all now approaching 50 years old, the amount of leakage in most of them has probably increased a great deal over what it was originally.

This inherent leakage in the control valve was not desirable in the fast hitch, so IH added a cross-check valve which bolts to the bottom of the control valve for the fast hitch. This is a rectangular block about an inch thick and maybe 3"x6" in its other dimensions, and the hoses going to your hitch cylinder should be coming out of this block. If you don't have this cross-check valve, your hitch is going to continue to bleed down until you get one - the only question is how fast the bleed-down will occur.

As far as your vice-grip control handle is concerned, I'd certainly try to replace it. I got a used replacement handle for my 300U from JP Tractor, but they are rather scarce and you may end up paying more than you really expect for one. Check the shaft on the control valve where the handle joins it - I'd be surprised if the splines on it weren't shot after being abused by the vice grips - so you may end up getting another control valve as well.

As far as the direction you move the handle to raise the lift: it's a little confusing on the 300U. The "proper" control handle was designed to wrap back up over the top of the control valve, and when you pulled up on it in this position, the lift went up. Since your vice-grip "handle" is pointed toward the front of the tractor instead of being wrapped up over the valve and pointing toward the rear as in the original design, pushing up on your handle lowers the lift. Unfortunately, reversing the hoses isn't really an option since the cross-check valve (assuming you have it) only works in one direction. If you put pressure on this check valve in the reverse direction, it just opens up, and the lift will leak down.

If any of this isn't clear, send me an email and I'll try to explain it better. I do have a couple of spare control valves and cross-check valves available if you end up needing one or the other, and can't find a reasonable deal elsewhere. Sorry, no spare handles, though. Good Luck.

dick

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