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Hitachi zaxis200LC-3 auxiliary pilot pressure loss

John Wellnitz

Member
Joined
Aug 14, 2019
Messages
5
Location
East Central South Dakota
Hi all! Long time reader, I’ve learned a lot of good info in here. I have an issue that I thought some of the gurus on here might have ideas on with a new to me Hitachi zaxis 200lc -3. Serial# ARH310868. I installed a hydraulic thumb and pilot pedal valve with the appropriate pilot hoses and pressure relief cartridges in the auxiliary outlets, (set to 3,000 psi for my cylinder) as per John Deere manual from our dealer for a 200lc Deere. My machine has the pilot manifold that the pilot hoses run to from the cab and then from there to the main valves. Pilot pressure from the pedal valve to the manifold is about 700psi, pilot pressure leaving the manifold and going to the auxiliary valve is considerably lower, especially on one of the circuits (300-400 psi.) It is enough to open the auxiliary valve each way and build to full pressure but it’s very slow. Also it doesn’t seem to be stroking the pump at all. When I hooked the pedal pilot lines to a boom circuit and ran the auxiliary valve from there it worked great. Fast and the pump ramped up immediately. It almost seems like there’s an issue inside the manifold on the auxiliary pilot circuit, which was unused since new. The ports were always sealed until I installed hoses, but is there any chance of gunk plugging up the internal plumbing of the pilot manifold? Is seemed pretty clean directly behind the original port plugs but I didn’t reach anything in there. I haven’t been able to find any electrical solenoids that would interfere, it’s all oil on the auxiliary circuit. Any switches I need to flip to allow the pump to stroke for the auxiliary? Thanks a lot for any insights! JohnW
 

John Wellnitz

Member
Joined
Aug 14, 2019
Messages
5
Location
East Central South Dakota
Thank you Deere35czts ! At the shop now, I just capped it and problem solved- the auxiliary hydraulics work great now. I had noticed that the SM port was circled in the instruction manual but somehow I missed the part about capping it off. Not surprisingly it comes back to my stupidity! I really appreciate you giving direction. This is why HEF is great. Thanks! JohnW
 
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