860 hydraulic pump rebuild

[wtcoyote]

With the help of this forum I narrowed down my hydraulic problem to the pump. Arms would not operate until engine ran at a fast idol for 15 to 20 minutes then would work intermittent and slow. Problem was air in the system. After bleeding the pump it would work just fine but if left overnight the problem would return. I ordered the kit and rebuilt the pump. The kit had an extra set of springs and also six new seats. I rebuilt the pump with out replacing the seats as my pumps seat didn't look like they were removable. Does anyone know if some pumps didn't have replaceable seats. My pump is working just great without the new seats but I would like to know if I am missing something. Were all the pumps made with replaceable seats and if yes how are they removed. thanks for any and all your help. This is a valuable forum. Terry
 

[Kurt-NEPA]

I did the same thing. I rebuilt my 660's pump without replacing the check valve seats. In my opinion, that is the right thing to do unless the seats are shot. Both my balls and seats looked like new, but the check valve springs were badly worn.

Did you replace the wobble shaft and seal. That is most likely cause of "loss of prime"?
 

[Keith Williams]

WTCoyote,
I had the same experience. My problem was the small cone shaped springs. I also replaced the bearings and the seal. Now works GREAT!
If I understand this correctly, the seats require a special tool in order to remove them because of the angle involved. I tried to remove one and could not get at it. Gave up since they looked fine.
After 3 years I am happy!
Good luck!
Keith
 

[wtcoyote]

Thanks to all for your input. I did replace the seal, all the springs, gaskets and ball valves. I did have trouble installing the small springs on the new valve plate and the roll pins were distorted from installation. I used an ice pick to hold the spring in place and another pick to work the small end of the spring over the pins. My pump is working just fine but was concerned that I wasn't able to remove the old seats.

Thanks again Terry