Jd 301 a 3PH not lifting

[liamtrac01]

I bought a Jd 301a from my neighbor. The 3PH lift is very slow…. Like multiple minutes to lift up. Looking for advice on how to fix it. What I have tried so far: I have loosened the small screw in front of the seat that is supposed to control the speed of lowering the lift. I have also changed the rock shaft control lever to all 5 different positions. When I put the lever in the position intended for the lift to stay at a specific height the lift shot straight up really fast. That being said I don’t believe it is a hydrologic pressure issue because it it can work. Non of the other positions seem to do anything nor will it move with the height adjustment lever when in any of the modes. My neighbor told me he hored a mechanic once that fixed it temporarily and it didn’t take the guy long and he refused to tell him what the problem is. Seems like a bit of a tall tale to me but that’s my situation. All that being said what should my next course of action be?

 

[Tx Jim]

First thing that I suggest to do is change hyd filter & check/clean hyd oil suction screen if these tasks haven't been recently performed. Next check hydraulic pressure which should be 2250-2350 psi. L/D lever under seat should be set in 'D" or "minimum" for all 3pt operations except when using ground engaging implements such as moldboard or chisel plows

 

[liamtrac01]

Thanks for the suggestion. My only thought though on it not being pressure related was when I moved it to the other position it shot up to the top. So my limited understanding would make me think that it has pressure. Can it have presser in one position and not another?

 

[Tx Jim]

You're welcome
Yes it can have ability for front pump to create pressure but have a large enough internal hyd leak that requires most of or all of the hyd pump output. Another possibility is pressure control valve mounted behind hyd filter could be blocking pressure &/or flow. Testing pressures with a gauge would determine if that is correct.

 

[liamtrac01]

You're welcome
Yes it can have ability for front pump to create pressure but have a large enough internal hyd leak that requires most of or all of the hyd pump output. Another possibility is pressure control valve mounted behind hyd filter could be blocking pressure &/or flow. Testing pressures with a gauge would determine if that is correct

You're welcome
Yes it can have ability for front pump to create pressure but have a large enough internal hyd leak that requires most of or all of the hyd pump output. Another possibility is pressure control valve mounted behind hyd filter could be blocking pressure &/or flow. Testing pressures with a gauge would determine if that is correct.

Ok that makes sense. A few questions. When looking at my service Manual. I cant find anything about a hyd filter. Is the hyd and transmission filter the same thing? To change the filter and clean the screen do I have to drain all the hyd fluid out? I was also going to adjust the flow control valve and check the spring my Manual said that could be the problem. Thoughts on that? Sorry for all the questions. Your answers are very appreciated.

 

[Jim.ME]

Yes, the transmission and hydraulic filter are the same filter.

Drain the fluid from the transmission/differential before removing the screen.

Do you have the technical (service) manual (JD # TM1088)? It will have the pressure testing info in it.

 

[liamtrac01]

Yes, the transmission and hydraulic filter are the same filter.

Drain the fluid from the transmission/differential before removing the screen.

Do you have the technical (service) manual (JD # TM1088)? It will have the pressure testing info in it.

Ok that’s what I thought. Yes I do have that manual. I will look for the pressure test. What do you think about the possibility of the broken flow control valve spring?

 

[Jim.ME]

Ok that’s what I thought. Yes I do have that manual. I will look for the pressure test. What do you think about the possibility of the broken flow control valve spring?

It might be a broken spring, or it might be something else. Does it steer ok? Does it have a loader on it? Reverser? Independent PTO? Those are some things that if they leak internally will cause problems. As Tx Jim posted testing is in order.