Anyone have any experience with Tiger boom axes mounted on late model Fords with gear pumps? I am getting whipped by a county rig that the main boom valve was leaking through and the pump was only putting out 1400 psi. I replaced the valve section (first in stack next to inlet/outlet block) and tonight replaced the pump. The valves as I can tell are power beyond which has a activation line going back to the factory auxiliary valve to block and divert flow through the boom valve stack, as does the three point lift valve also, which is working fine. Now, it is either deadheading the pump unless I dump the one way boom valve, which nothing past that section is working, dumped or neutral, or it won't send the divert signal for pressure to do anything. I can activate the auxiliary valve and get some of the functions to work as it seems to pressurize the stack. Sometimes with it deadheading, I could barely dump the one way boom valve and get other functions to work, but usually not. When I finally gave up, nothing past it worked at all. I've never seen a valve section like these that only has a single large outer o ring between them and the machined surfaces seal between pressure and return. The top cap has the line out for divert function and each section has a check ball and spring with flow going toward the end cap. My experience is limited to closed or open center valves so I am lost as what could be wrong.
I don't see anything unusual about that stack valve, but would need a schematic to begin to understand what you're talking about. That's most likely an open center stack, but could be closed, it's hard to tell from a parts breakdown.
lantraxco, all of the sectional valves I've dealt with have o rings around each port between them(usually 4) so this is a new one on me. I don't have any more info to go on than a parts manual. The top end cap has no large galleries so the oil flow must turn around somewhere inside the valve sections. As the existing cap doesn't match the illustration, I think it is the reference #3 which is for power beyond as the others are closed or open center.
Power beyond just sends the oil under pressure to another valve for more functions, sounds to me like it's going around in a dead end loop....