I've spent so far 3 days working on the old girl. I looked at pretty much everything to do with the steering and I'm thinking the MCV pump is bad. No Power steering. I want to figure a way to test the pump without those special tools. If I raise the front end with the bucket, the steering works great. LOL I pulled the Relief valve, removed the check valve fittings and cleaned it up, removed other fittings looking for more check valves or obstructions, I pulled the flow diverter and cleaned it up a bit, and even blew through some of the lines to check for restrictions. (NOTE: I found some pieces of rubber in the Diverter Valve (looked like O-Ring pieces but I didn't find any obvious missing O-rings. If I remember correctly the loader was a bit weak the last time I used the machine and that is when the steering went haywire. At one point both front wheels flopped to the right and the steering wheel wouldn't work but.. the machine recovered and I finished what I was doing. I noticed when I picked up a large scoop of dirt the power steering would give me trouble. It took both hands to get the steering to function, then it would clear up and work a while. Strange but... I'm still trying to determine the best repair path. I'm getting tired of removing all the Hydraulic fluid and laying underneath this baby. I am getting tough though... better than working out, climbing all over this thing. LOL Is there anything else I can/should check ?? Thanks in advance.
I would start with a pressure test. I've never worked on the steering of an IH 3400A, but it could be as simple as a fatigued spring in a relief valve.
I removed the RV and it didn't look suspicious. LOL Problem is I don't have the equipment to do the tests but I'm sure I can figure something out..... good calisthenics for me. Up down, up down, reach pull..... contort my body in positions it hasn't been since the last time I worked on this thing.... walk and get tools.... repeat. LOL What surprised me was when the front wheels just moved all the way to the right as I was backing up with a load. It dug a hole but backed out and after a bit of manual steering... corrected itself.
No help from me but I have the same sort of problem in my 3400a. Sometimes the steering only needs one finger on the wheel, sometimes it needs both arms and a leg.
don't that model have a switching valve on fender for steering in one postion and swing in other postion?
It is an old machine and I don't have an operators manual but I don't see a switching valve. What I do see is what the call an IPTO something or other that has a knob on it and it moves up and down but... it just springs back up when I push it down. It is on the left side of the tractor and located on the MCV Pump valving. I tried pushing it will operating the steering and nothing happened. I am interested in what you said and if you can provide more information I would appreciate it. Also, I believe the loader was not as strong as it was previously and this ocurred about the same time the steering had issues. The MCV pump takes care of the steering and also is a make up pump for the loader providing about 4 gallons a minute to the loader. The main pump is pretty new thank goodness which means the MCV pump may be the problem. I am getting awful tired of draining the oil from the transmissions. At least I have the old girl working... save the steering issue so I can move her around. I think I am going to sell the machine when I get her up to speed. There won't be much I have not worked on for sure. It would have been nice if parts were more readily available.
Chad... if this is happening when you are carrying a load in the front end loader.. that is when my problems started. The gentleman I talked to today use to work on this things. LOL He said my warning that it was the MCV pump was when it first gave me trouble. He doesn't have much faith that the problem is a valve. I am inclined to agree. As I mentioned the MCV pump provides power to the loader and the steering. There is also a diverter valve that can cause problems but I did not see a problem with that valve. I removed it and give it a polishing and reinstalled it. The relief valve..well.... it was an assembly and it looked like everything was in place to me. I did remove it and fondle it a bit before I reinstalled. Test your machine and post up. Currently my machine has ONLY manual steering... that means to me that I have to provide all power myself to get things a werkin. LOL When I life the front end using the loader... steering stop to stop is easily accomplished VIA Power steering (yes it is the power from the tractor not me. I can tell the difference). As soon as a I lower the bucket it gets more and more strenuous and I do not hear the fluid flowing and I get a lot of chatter. I'd like to think I need to bleed the system better but.... we shall see. I am in no rush to remove the pump but at present... it looks like that is the best repair path. Good Luck
It doesn't seem to matter if I have a load or if the bucket is up or down. One moment the steering is bad enough to make me think that the machine has serious problems and then a few minutes later it works fine and I just put my head back in the proverbial sand and forget all about it. Losing power steering is much less concerning to me than the clutch slipping 100% occasionally or the dipper bushing that seems to be wearing at a rate that I can see with my naked eye. I will certainly pay better attention the next time I lose power steering and I will post the details.
Also, although it is likely to cause me an ulcer thinking about it, what is the MCV?
I am jealous that you don't know where this stuff is located. LOL That means you have a good machine. MCV (Multiple Control Vave) controls the steering and loader ( percentage of the loader flow) The valve block has a flow divider valve, relieve valve an IPTO (which I don't know that does, perhaps that is of those models with the standard 3 point hitch attached.) There a little check valves on a line or to and a couple of other items. It is basically a control system. I'll figure this out and post up. I don't like changing parts without good reason and I feel the same way about delving into the inner bowels of the system. Ha ha FYI the MCV pump is on the right side of the tractor below the seat. The outer unit is shaped like a dome. I want to insure that the pump ans system has adequate fluid flow to the pump suction. Can't pump without something to pump. On a side note....I have an airplane that is a 1972 and as I work on it, I witness the result of many hands at work over the years. Fortunately, there are strict rules and yearly inspections to insure the plane is pert nearly as designed even after 44 years.
MCV & Pump Repair OK... got tired of fooling around. Drained the fluid and pulled the MCV and Disassembled the Hydraulic Pump. Check out the pictures and advice would be appreciated. Lots of sludge and gook around the System RV. I ignored this on my checks because it seemed this was only used for the 3 point lift which I don't have. I don't know how much wear is tolerable on these pumps. The gear teeth have some slop and you can see the scouring. Perhaps this is enough to cause problems. I'm not sure. The pump is a Cessna. There is some wear on the gear teeth which I have not measured. It is a decent amount of slack and may be enough to affect pressure output. Input would be appreciated. On the next Post I have another question... LOL
Here is another picture of the internal view of the MCV. The Gasket is attached. You can see the amount of sludge around the system RV. Can someone help me figure out what this IPTO thing does. LOL It moves easily up and down but I can't figure out what it is supposed to do. LOL Help is always appreciated.
That housing is well hooped.
lantraxco - In your opinion, do you think the pump could be the issue? I plan on replacing it but I want to get this part of the system up to snuff. I am going to remove the system RV and check things a bit more closely before I reinstall the pump.