Bobcat 610 speed change valve ball

[rnbuck01]

I got a variable speed valve taken apart because it is leaking down and there is 3 balls that were in there, 2 balls had a spring with them and cannot figure out where the other ball goes.

 

[6brnorma]

So….if the valve were mounted and in operation (at operators left side)……there are two ports at the bottom of the valve. The forward most port has a plug in it…….ball goes inside that port above the plug.

 

[6brnorma]

So….if the valve were mounted and in operation (at operators left side)……there are two ports at the bottom of the valve. The forward most port has a plug in it…….ball goes inside that port above the plug.

rnbuck….This does not appear to be a valve that came original on a M-610……could you give me a serial number of the machine.

 

[alchemysa]

rnbuck….This does not appear to be a valve that came original on a M-610……could you give me a serial number of the machine.

Theres only two shown in this pic. (17) and (22).

 

[6brnorma]

Theres only two shown in this pic. (17) and (22).

I find 4 different valves used …….. One had only one ball, two had two and one had three. As far as I can tell …. all are Gressen valves, unfortunately I am unable to find any "Gressen" valve body part numbers in Bobcat parts books…….only Bobcat numbers which are not stamped on the valve. I do have 'some' serial numbers that the different valves were mounted on……..that's why I asked him the serial number of his machine……it does not appear to have ever been used on a M-610. I must assume therefore that either he does not in fact have a 610 or a valve was pulled from another machine and installed on his. Without a response from him…….guess we won't know.

 

[rnbuck01]

I find 4 different valves used …….. One had only one ball, two had two and one had three. As far as I can tell …. all are Gressen valves, unfortunately I am unable to find any "Gressen" valve body part numbers in Bobcat parts books…….only Bobcat numbers which are not stamped on the valve. I do have 'some' serial numbers that the different valves were mounted on……..that's why I asked him the serial number of his machine……it does not appear to have ever been used on a M-610. I must assume therefore that either he does not in fact have a 610 or a valve was pulled from another machine and installed on his. Without a response from him…….guess we won't know.

Does the bigger balll go on the inside then the spring then that little ball goes against number 25 in the picture for the pressure release? I'm having a problem where it won't hold the pressure and leaks down.

 

[rnbuck01]

Does the bigger balll go on the inside then the spring then that little ball goes against number 25 in the picture for the pressure release? I'm having a problem where it won't hold the pressure and leaks down.

I think I might try and check opting on seat but it won't come out.

 

[6brnorma]

I think I might try and check opting on seat but it won't come out.

I have 20 or so old manuals…..it is interesting when something like this comes up and forces me to dig through all of them. So, in researching this morning I have found two more valves……one so old that none of us probably have one and one fairly new and may be what you have. I don't know that I have one of the newest versions as that valve fails so seldom that I don't dig into them all that often.
Alchemysa's exploded view will be very helpful. First….I think I said the two ports face down when they actually run horizontal to the seat when mounted. If there is no fluid leaking from the valve……I generally find the problem in the 'holding pressure' adjustment….Parts #15 ~ #19. Removing the seat (#18) to get to the O-ring (#19) can be very tough without special tools. You can deform the seat face if you are not careful so I generally leave it if it does not come out fairly easily. Obviously…..if the o-ring is the problem…..you will need to go to a hydraulic shop for help. The ball in that one mics at .375. The spring in that one is the heavy spring and mics at roughly 1.030. These will vary slightly as Bobcat instructs you to grind some off the spring if pressure is too high (which would not be your problem). They instruct you to close the plug (pt #15) by a quarter turn until you have 600psi (in some cases 700psi). If the plug bottoms out before achieving the required psi you are instructed to add shims between the plug (#15) and the spring (#16).
The exploded view that I have of a valve using the third ball is a newer valve and the ball is larger in the drawing and is placed in the forward most port under plug number 20. Again……I'm not even sure that I own one of this style valves as they fail so seldom and if I did work on one, I wouldn't have even pulled that plug thinking there was nothing under it anyway. I learned something here.
Rebuild the entire valve while you have it off and apart. All of the seals in these valves can be easily obtained at any hydraulic shop for a few dollars.

 

[6brnorma]

I have 20 or so old manuals…..it is interesting when something like this comes up and forces me to dig through all of them. So, in researching this morning I have found two more valves……one so old that none of us probably have one and one fairly new and may be what you have. I don't know that I have one of the newest versions as that valve fails so seldom that I don't dig into them all that often.
Alchemysa's exploded view will be very helpful. First….I think I said the two ports face down when they actually run horizontal to the seat when mounted. If there is no fluid leaking from the valve……I generally find the problem in the 'holding pressure' adjustment….Parts #15 ~ #19. Removing the seat (#18) to get to the O-ring (#19) can be very tough without special tools. You can deform the seat face if you are not careful so I generally leave it if it does not come out fairly easily. Obviously…..if the o-ring is the problem…..you will need to go to a hydraulic shop for help. The ball in that one mics at .375. The spring in that one is the heavy spring and mics at roughly 1.030. These will vary slightly as Bobcat instructs you to grind some off the spring if pressure is too high (which would not be your problem). They instruct you to close the plug (pt #15) by a quarter turn until you have 600psi (in some cases 700psi). If the plug bottoms out before achieving the required psi you are instructed to add shims between the plug (#15) and the spring (#16).
The exploded view that I have of a valve using the third ball is a newer valve and the ball is larger in the drawing and is placed in the forward most port under plug number 20. Again……I'm not even sure that I own one of this style valves as they fail so seldom and if I did work on one, I wouldn't have even pulled that plug thinking there was nothing under it anyway. I learned something here.
Rebuild the entire valve while you have it off and apart. All of the seals in these valves can be easily obtained at any hydraulic shop for a few dollars.

Thanks for the drawing Alchemsya.

 

[6brnorma]

Thanks for the drawing Alchemsya.

rn…the answer is no……you do not put two check balls in any one port. One per port only. Again…..it might help if you could supply a serial number from your machine.

 

[Unicam]

rn…the answer is no……you do not put two check balls in any one port. One per port only. Again…..it might help if you could supply a serial number from your machine.

This was the problem when mine wouldn't hold pressure. The previous owner had someone "rebuild" the valve asm, after the rebuild they had to hold the lever forward with a bungee cord, not knowing why. They installed the ball #22 first, then spring #21. The spring goes in first as shown in the diagram. So presumably if there is an improper seating at that location for whatever the reason, It could lead to not holding sheave position.