hydraulics

[CheapTractor]

Have recently acquired an old MF65 diesel. When the tactor is shut off 3 point hitch bleeds off and arms drop to lowest position. Changed the hydraulic fluid with 90W Mineral Oil. Now when the hydraulics is raised get a jerking motion as it raises. Notice also when hydraulics is activited system cycles of lifts and lowers in a second. Lever is not being moved as the system is raises or lowers. I guess for a better definition or explanation the hydraulic system lopes with a load and hydraulic lift arms still drop to the lowest position for the a better word.

Can the internal hydraulic system be rebuilt or will a new internal hydraulic pump have to be purchase?

Thanks,
Cheap Tractor

 

[Muhammad]

Welcome to TBN.

 

[SPYDERLK]

I think 90 wt is far too heavy until the fluid gets hot. The pump is having a hard time pulling the fluid in when cold and so you get voids in the pumped fluid and it jerks. Will probably smooth out when hot. The leaking down is another issue. What you are seeing is the leak interacting with position control when its running. It leaks down a little then corrects over and over. It may be debris in the internal valve or just wear. Id give it a little time and exercise and see if it improves before finally going into it if needed.
larry

 

[CompactTractorFan]

Welcome to TBN!!! Try the Hydraulics section.

 

[g0rd0]

you could try this I have done this and it cleared up the sluggishness in my system
drain your fluid, replace it with diesel fuel run tractor cycleing your hitch (and steering if the steering uses the same system) for about 5 minites.
drain this diesel, replace the filter and replace the system with clean 32 weight hydrolic oil
your preasure should be good, as for the dropping of the lift at the connection of the leaver or maybe infront of the centre of your fluid resivoir there maybe a small knob that you can turn to adjust the lift preasure with