Hey, got a Komatsu WA380-6 that all of a sudden had low work equip pressure. I tried to adjust the main up but it did nothing. The unload p is also lower than spec, ppc pressure is 20 psi from spec (pretty close). If you put the throttle all the way down, the arms can be lifted up. If you dont, they dont move. Bucket curls with out throttling up but is very slow. Think a main relief would be doing this?
I assume you were using a gauge when you tried to adjust the MRV pressure?What's your actual MRV pressure set to at the moment?
Yes, a digital tifco gauge. It is at 3400psi right now. should be at 4350+-220.
Pull the MRV cartridge out and make sure there's nothing blocking the jet bore, if it is blocked then adjusting the pilot spring will have nil effect and the relief cracking pressure will be considerably lower. Have you tried adjusting your PPC pressure? If not then check it too for blockage. Could well be something on its way out and contaminating the system.
I did some more troubleshooting on it and decided it must be the the MRV. Put a new one in it and prob went away. FYI.
Hello, I have some questions about this same loader if its still up for discussion. I have a WA380 with about 4500 hours on it. it has the Cummins engine Cid/L 505/8.3. We have owned it about 6 or 7 months, bought it from a Komatsu Dealer locally. Anyways the crank shaft broke couple days ago. Any experience, has anyone had this problem??? Thanks\
Another cause of problems of this type is if you have an O-ring disintegrate into the hydraulic system and pieces can get lodged in the relief or control valves. And to flush a hydraulic system is a real pain. It's the one 25 cent o-ring that can take down the million dollar machine. Glad you found your problem.
A thank you to Chris 5500 would have been nice... -.-