I just recently bought an 05 PC120 from a private party. Everything on the machine seems good except the arm speed, and sometimes the bucket. I've tried all the digging modes, including active mode. I changed the hydraulic filter also, nothing seems to improve the speed. I called the Komatsu dealer they told me to change the filter which I did. I'm hoping someone had a similar problem and knows a solution. Thanks.
Has there been hoses changed over to change control pattern ? One could be put on wrong. Is there a third valve for thumb ? sticking , plumbed wrong? Is there any recent hydrualic work done , that could be a culprit?
Yes there was hoses changed for the control pattern. A komatsu mechanic changed the small hoses from the controls at the valve body in the compartment right behind the door. I had the controls changed from ISO to John Deere. I don't know which hoses are supposed to be where, the are all color coded. I don't know which ones he switched, but if they are wrong, wouldn't the controls be screwed up? When I bought the machine I couldn't really tell the speed because of the switched controls, but it is definately slower than machines I operated before, and it is newer.
I had the same thing on a KObelco. The hoses were switched and slowed the stick. I guess they were hooked up where they should go so the stick worked , but they had to be reversed from top to bottom of valve block. I dont know if this is your problem, but problems like that usually result from recent work. GOod luck, doug
butchyd... It's not clear from your thread whether the arm speed was acceptable to you or the previous owner before the controls were switched over to JD type. If they were then the controls must have been switched on the wrong side of the junction block so the controls will function but not as designed.
wulf, I couldn't really tell if the speed was good, I didn't use it much with the opposite controls. The hoses were changed on the cab side of the valve box. (the hoses directly from the joysticks).
please try to emphasis I think I can help you - the standrad speed for arm is 3.2 +/- 0.4 sec for IN movment - the standrad speed for arm in 3.1 +/- 0.3 sec for Out Movement (this figures with active mode / engine full rpm, oil tepreture with in operqating range) if your figures doesn,t meet the standard tell me - What is the service meter reading for the machine now - Only the arm has this or other work equipment - The problem exists during all operations or compound operations - what about the repair history for the machine espicially hydraulic system - do you have any tools for further investigation or for any measurment you have to call the dealer Thank you
...How about just taking it in to the komatsu mechanic? :cool2 Blake WA
One of my machines had a slow stick cylinder and a slow bucket cylinder. It ended up being a valve sticking in the valvebody.
Here's an east way to remember... Pressure is power and Flow is speed. So if you have good speed in all other functions, verified by a cycle time test, then all you have to do is look into that one function and you'll find your problem.