Foton 254 priority valve

[valley]

Greetings, FEL not operation not satisfactory so I opened the Priority Valve.
I found no crud to speak of, I want to show all the pieces If you see any thing out of order please let me know. Richard

 

[valley]

This is the order of the valve parts:

 

[valley]

I'm wondering if the valve could have been taken apart and assembled wrong.
Have a look at this slid or spool.

 

[valley]

this was placed in as shown laying as shown next to the valve body. Could it have been turned around?

 

[valley]

I'm going to assemble the valve and reinstall. I was hoping to find enough mess in the valve to see that the valve was at fault. Richard

 

[3RRL]

Hi Richard,
I know nothing about priority valves, not having one on my tractors.
But as far as checking it out, one way to determine the best function of that spool piston is to measure where the openings end up when it's position is moved. The holes appear to be at different dimensions from the ends. Perhaps one position lines the holes up better during use? Do the ends have the same depression, are they the same?
What function do those grooves on the piston have? I saw you used snap ring pliers to remove the retainer ring in the valve itself, but they appear to fit on the ID of the bore of course, or you couldn't get the piston out. So I'm wondering if those grooves are for "O" rings, quad ring or a similar seal?

 

[valley]

Rob, The ends of the slid or spool are different. There is a snap ring on one side. the grooves can't handle an 0ring. I wondered why there are two groves on one side and one on the other.The holes seem to be the same demention. I was somewhat tempted to make the hole in the end slightly larger but resisted.

 

[Diamondpilot]

Don't make any mods to the valve. I still think your problem has a lot to do with needing a flush of the system and a good AW32 hydro fluid that is non foaming.

Chris