175 3 point lift response

21hunter

Member
Hello, the 3 point lift on my 175 is slow to respond with the position lever. It is most noticeable when lowering the lift with an approximate 2-3
second delay from the down movement of the position lever until the arms start moving down. I was using a grader box this weekend and the
slow response makes it more difficult to do a good job. Does anyone know if there is a way to speed up the response? Could the dashpot
cause a delay? Is the dashpot necessary if I don't use the tractor for a mounted plow or other implement where I use the draft Control? I've
tried different draft and response lever settings to no avail. A new lift pump was installed and the hydraulic system was adjusted according to
the repair manual........so I thought.
Thanks
 
Hello, 2-3 seconds is a miniscule amount of time but where you have an operation that requires constant adjustment it must be infuriating. When the adjustments were carried out etc were the appropriate MF special tools used? The dashpot is very important when using a soil engaging implement or something heavy that you wish to control the 'drop' speed on. For normal use it should be set to the 'FAST' end of the sector. Was the control spring in the rear of the hydraulic cover removed and adjusted and then further adjusted for end float when refitted? Any excess looseness in the spring, tightness in the control beam etc can affect the operation.. A check that you can carry out is to drain the oil to the level of the bottom bolt on the RH side cover and remove the cover. Operate the quadrant lever in its normal range and observe the operation of the pump lever as actuated by the vertical lever. The roller on the pump lever should be in contact with the knurled screw on the vertical lever at all times. If a gap occurs between the roller and screw which then closes after the 2-3 second delay it would suggest that the control valve in the pump is not sliding freely. This could be down to damage on the valve where it slides in the precision ground washers, misalignment of the washers or incorrect assembly. There is an oscillating link under the pump which maintains a constant back and forth movement to prevent the valve sticking. Has this been replaced correctly? With the engine stopped operate the pump lever by hand. It should be perfectly free. Any sign of fouling will indicate that that is where the problem may well be. Let us know what you find.
DavidP, South Wales.
 
Problem solved! The adjusting screw that contacts the control lever was not screwed out far enough and was not actuating the control lever enough to dump the pressure and lower the lift. Played around with it some to get good response in up and down position. Another question; is it characteristic for the lift to be a little wobbly on these tractors? I'm used to operating others that are not like this. Even my old Jubilee ford is much smoother but it has a vane pump with the Ferguson style lift system. The old pump was wobbly and I installed a new pump which is similar although not as bad. I figure that it's because of the 4 piston scotch yoke pump which isn't nearly as smooth as a gear, vane or variable displacement piston pump. Of course when you speed the engine up, it gets smoother.
Thanks
 
Hi, glad we are on the right track. As to the Ferguson linkage pump being a 'bit wobbly' this should not be the case if all 4 piston rings are good and the poppet valves are sealing correctly. Does your tractor have Pressure Control (front side of the inner quadrant)? If so this erratic lift may be down to adjustment of part of the PC system which in adjusting the lower knurled screw have changed from its original setting. In order to set this correctly you will need the MF 270B piston wedge tool and a pressure gauge. You may be able to carry out a less accurate adjustment by raising the lower links until the relief valve blows. If this adjustment is incorrect the the pump lever should begin to oscillate back and forth and a strong jet of oil will be emitted from the diaphragm housing just above. Adjust the screw until the oscillation reduces and a smaller volume of oil is emitted from the diaphragm. I cannot be sure that you can carry out this adjustment without the MF 270B tool as it has always been used. I believe that in the US this and most other special tools have different numbers. PT, Dieseltech?
DavidP
 
I don't mean to overblow my statement of being wobbly. The lift does operate pretty smooth. It?s just has a very slight jiggle that is barely noticible. Just not quite as smooth as my 2-105 white, my 656 International or my Ford Jubilee, all which have a vane, gear and closed center multiple piston pump. The old pump definitely had a bad cylinder or check valve. The new pump seemed very even on all four cylinders in sound an feel when rotated on the bench. I did the pressure setting and ended up with 2500 psi. I had the draft Control all the way up and the position Control to constant pump to bottom out the lift assembly to push the pressure against the relief. I could go back and re-check the pressure adjustment. There is a small oil jet coming out of a pin hole in the diaphragm housing but it isn't real strong. One thing that I didn't mess with is the pressure control valve with The adjusting tube on it. Does this valve require any adlustment? I only. Adjusted the small screw that contacts the pressure. Control diaphragn stem.
 
Hello,if you have 2500psi on a test gauge that is fine. The MF manual says that early 175s should be set to 2350 +or- 50psi. Later 175s can be set to 2550psi + or - 50 so you are bong on the mark there.

DavidP
 

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