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Loader Arms

K

KAC=CATeater

Member
Joined
May 22, 2009
Messages
13
Location
Northeast
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?
 
Chris5500

Chris5500

Well-Known Member
Joined
Oct 23, 2009
Messages
217
Location
Australia
Occupation
Plant Mechanic
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?
 
Chris5500

Chris5500

Well-Known Member
Joined
Oct 23, 2009
Messages
217
Location
Australia
Occupation
Plant Mechanic
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.
 
C

CTXINCCONST

New Member
Joined
Dec 15, 2011
Messages
1
Location
Connecticut
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\
 
D

Davvinciman

Well-Known Member
Joined
Nov 29, 2011
Messages
82
Location
So. California
Occupation
Operating engineer and business owner
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.
 
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