I’ve got a 2002 komatsu pc150-6k 5200 hours, the machine runs perfect for the first 10 minutes plenty of power will spin circles with the tracks in high mode, then once it’s warmed up it will barley pick it self off the ground with using just the boom, every function seems to slow it’s almost like you can hear the fluid bypassing too soon like the reliefs were all backed down suddenly. Komatsu came out and the guy worked on the machine for 3 days replaced the governor linkage changed all hydraulic fluids/filters, tested pump pressures after machine was hot and said all pressures were normal, the actuator on the turbo was broken and he insisted that was my problem, I put a new turbo on the machine and that didn’t change anything. So after komatsu left me with a fat bill and a machine that’s still not working right I decided to crawl around and found the wiring to the epc solenoid was torn out so I replaced that hoping that was the problem but no change. I cleared the codes on the machine and ran it after the epc solenoid was replaced and I haven’t got any new codes and the hydraulic oil seems to be getting way hotter than it should be. This thing is driving me crazy any suggestions would be much appreciated, I really don’t want to call the dealer back out to walk around the machine for 3 more days scratching their head at my expense
Do you think those hours are even close to original? Do you have a serial number. Back then all the machines made for the states had a serial number that started with an A. Sometimes in the pump you get scratches on the seal plates and barrel assemblies that cause them to leak by and cause heat. There were a lot of issues with compensators back then as well and I remember a little spool that had something to do with the swing that would actually turn black from the heat when it would actually spin in its bore. Have you done any cycle times on the boom up function? It should be around four to four and a half seconds from the ground to top out with the pump and engine in the high modes.
Hey thanks for the reply! Hard to tell if hours are actual or not the machine is in decent shape but who knows, the serial number the dealer gave me on the paperwork is k34088 so who knows what I’ve got here, cycle times are all good machine is perfect at start up, the monitor panel in monitor mode is showing 350 bar at relief on all functions then after the machine is up to operating temp I can only get 220 bar once the relief kicks in, all of this is in HO mode with the active button engaged.
As far as I know the "K" serial numbers came from the UK or Europe. My thoughts are that the pump is probably getting weak. In normal operation the pump will destroke at somewhat less pressure than the main relief. When you operate the active mode button you get the higher output on the pump and go over the main relief at the same time for seven seconds. After that the computer drops you back into regular operation. Try checking pressure two different ways. Setting the swing parking brake to on gives you the higher output for as long as the brake is on. The travel functions always give you the higher flow and pressure as well. Blocking a track with a pin between the sprocket and the track frame is the best way to check the individual pumps.
Tested again and as before everything is normal in every setting until warm and then every function slows, in every mode and setting, could it be the pilot pump on the machine going bad? I will attach a photo of my pump
That isn't a pump that I am familiar with. It appears like it has only one piston and barrel assembly. You can check the pilot pressure right at the pump. The red cover is over the top of the Komatsu quick connect fitting. It should be at least 300 PSI at all times. My thoughts are still that the main pump is getting weak and will need to be torn down, inspected and likely needs a new piston and barrel assembly.
Hey just an update on the machine for anyone else who may be having the same problems I did. I ordered a new main relief valve and put that in and the machine seems to be working good as new, I will give it a few weeks too see how it seems to hold up!