670 raise/tilt won’t activate compensator pressure to raise pressure for operation. The long arms works good and raise/tilt will work with button pushed for long arms. Has to be something stopped up in control valve I believe. Any suggestions on how to repair with out removing control valve
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670 Hydra-ax hydraulics
- Thread starter RickyHol
- Start date
daveyclimber
Well-Known Member
Check pilot pressure
akkamaan
Active Member
What kind of equipment is the "670" and what brand/model are the directional valve and the pump?
Do you get pump pressure activating any other functions?
I assume you have a CPU or LS hydraulic system with a variable displacement pump. If so there is a hydraulic line, probably 1/4" in size, that transfers a pressure signal from the directional back to the pressure compensator on the pump. How this pressure signal is generated depends on who made the directional valve. So just now with limited information, the only hint I can give you is that there can be a small orifice, 0,7-1.0 mm diameter that is clogged up with debris.
This is Parker's way to design a CPU, Constant Pressure Unloaded system.
The orifice is located between the main pressure line from the pump and the signal line that goes back to the pressure compensator on the pump
Do you get pump pressure activating any other functions?
I assume you have a CPU or LS hydraulic system with a variable displacement pump. If so there is a hydraulic line, probably 1/4" in size, that transfers a pressure signal from the directional back to the pressure compensator on the pump. How this pressure signal is generated depends on who made the directional valve. So just now with limited information, the only hint I can give you is that there can be a small orifice, 0,7-1.0 mm diameter that is clogged up with debris.
This is Parker's way to design a CPU, Constant Pressure Unloaded system.
The orifice is located between the main pressure line from the pump and the signal line that goes back to the pressure compensator on the pump
daveyclimber
Well-Known Member
A 670 is a rubber tired feller buncher. Personally I own a 2670 which is a ewer variation once Prentice took over Hydro-ax. As far as I know the hydraulics are load sense at least on my unit. On a 2670 there is a load sense filter located on the pump below the air filter housing and charge filter along the frame rail. Fairly easy to miss since it is about the size of a 1/2" drive socket. I have cleaned them in a pinch with no ill effects. Additionally there is an orfice located on the main valve block which is in the front compartment in between the loader arms. My machine is newer and uses a different valve block than the older 670 so I can't really help you find the location.