Lift Arm Hydraulic Problem On A 135


New User
I have a 1965 gas 135 with a loader installed on the front and I'm trying to work out problems with the hydraulic system. I bought the tractor a few years ago and the rear lift arm and bucket hydraulics have never really worked properly since I bought the tractor. The tractor itself seems to be in pretty good shape though, and it suits my needs well for what I need.

So here's the main problem. Like many of the posts I've researched here, my lift arm leaks down (within a half hour or so I would say) when the tractor is turned off, that doesn't really bother me too much since it comes back up when you start the tractor back up. The main problem I have is that when you try to set the height of the lift arm for either mowing or tilling, and you get it where you want it to start working, as you start moving along, the arm changes position on its' own and either goes up or down to an extreme. When it goes up too far, it's hard on the connected drive shaft and drive train obviously, and I constantly have to fight with the lift control to try to maintain a constant height, unless the lift control is in the full downward position. Basically the lift arm wants to be either all the way up or all the way down unless I'm fighting with it, which doesn't make for a pleasurable old tractor experience. lol

The other problem I've found is that when I want to operate the front loader, I have to drop the 3-point lift arm all the way down, prior to switching the diverter control over to operate the front loader, because if I don't the front hydraulics won't work at all. Even when I do this the loader hydraulics are slow and pretty weak. I don't know how fast or strong they actually should be on this old of a tractor since I'm more accustom to modern hydros on my skid loader and other heavy equipment, but I think that they should work better than they do. I'm not sure if the loader problem is related to the lift arm problem, or could be related to the poor leaky job they did piping them in to the diverter valve on top of the top cover.

I should tell you that I am using the Traveller Premium Universal Tractor Trans/Hydraulic fluid from Tractor Supply in the tractor. Don't know if that matters, but I saw that some on here recommend it.

From researching other posts about this subject, my plan of attack is to check the following in the following order, and ask if this sounds like a good plan of attack?

1- Mesh filter inspection and cleaning
2-Oil leakage from lift cylinder inside
3- Turbulence around the relief valve inside
4- Check adjustment and condition of lift valve linkage inside
5- O-rings on the lift tube under the diverter valve
6- Replace the diverter valve (I don't like the one on there anyway and it weeps oil)
7- Piston and ring replacement
8- Pump replacement

Thanks in advance for your help everyone. Tim
Hello Tim, plenty of info in your posting describing the problem. If the 3-point linkage goes down in anything over 10 minutes, that is completely normal. On safety grounds there is no reason to leave an implement in the raised position. Selecting 'external' on the isolating valve will normally increase this time. From your description it would appear that the 3-point linkage moves of its own accord without any change of position of the Position Control lever on the quadrant.
Your plan of action would be fine for faults where the efficiency of the system is in question. Your problem would appear to be more operational.
If the 3-point does not respond to commands from the quadrant lever, this needs to be investigated first.
Drain the transmission oil to the level of the bottom bolt on the RH side cover. Inside you will see the pump lever coming up out of the oil. You will see the vertical lever coming down from above and should be located behind the pump lever. Pressure from the control valve spring will push the pump lever rearwards. Familiarize yourself with the way the system operates as follows:
Engine off, 3-point linkage down, Position Lever down, Draft lever Up.
The pump lever should now be leaning forward. Move the Position lever to fully raised. The pump lever should now move to leaning fully rearwards. Have an assistant lift the 3-point linkage by hand. As the linkage approaches full lift the pump lever should take up a near vertical position as the control valve moves into the neutral position.
Have your assistant hold the linkage at approximately half way. Lower the Position lever. The control valve lever should now move forwards into the discharge position.
If the above does not occur smoothly and instantly it would appear that there is a fault within the linkage in the hydraulic cover. The likelihood is that the Position Control frame will be bent or broken in some way. There is also a fine spring which holds the frame in place. You may not be getting full oil flow to the linkage, this would tie in with your loader problem.
If you can pinpoint whether the internal linkage is working correctly then you can move onto the next step.
DavidP, South Wales
David- Thank you very much for your reply. I will do as you have instructed, however I probably won't be able to work on the tractor until early next week at the earliest. I'll post the test results as soon as I can get to the tractor. Thanks again for your help. Tim

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