I recently bought a Komatsu 150LC-3. The machine will move fine when first started, but as it warms up, will lose drive power. I was told the swivel joint is the problem. All I have done so far is to change all the oil and filters. This includes final drive oil. It appears to have plenty of hydraulic power although I feel it needs a lot of throttle to accomplish this. I have only run a JD70 in the past. The hydraulic pumps whine a lot compared to my deere. I feel there is a different problem, cause it will get so that there is no track movement at all after a half hour operation.
More than likely the biggest problem with your machine is that the hydraulic system needs to be tuned back up to factory specifications. If the swivel has a problem the machine will not track straight but that might be difficult to diagnose if the pumps are out of adjustment. Check your return filters and if there was any white or blue colored packing in there your swivel is likely a problem. The swivel is pretty easy to repack if you need it. You will likely need a dealer wrench to come out and adjust the system first and then check the travel. The key is having them adjust the proper functions. There are three items that need to be adjusted. The first is the negative control which is adjusted at the outlets of the main control valves. The second item is the main reliefs for each valve and finally the cut out functions need to be adjusted. After that you should be able to walk the machine straight ahead for 50 or more feet and it should not track off to one side or the other. Good Luck!
Thanks John C. Are you referring to the term negative control as the pilot pressure system? Why would I be able to use the other functions when the travel fails? I did not see any blue or white packing in the filters or sump when mucking it out. Will probably still repack the swivel to eliminate any leakage to the return circuit. Mike S.
Pilot pressure runs everything and is supposed to be around 426 PSI. Usually if you have a problem with pilot pressure the implements don't want to work right either. The travel circuit runs at a higher pressure by way of a two stage relief valve. The higher setting is done with a solenoid valve when you actuate the travel pedals. It also works on the power up button for a few seconds and when you set the swing brake. The cutouts have to be set high enough to give flow at the higher relief settings. If they are set low the pumps will destroke and give you less flow which will change your speed and power. You will notice the affect when walking up a hill. Negative control is what actually gives the machine load sensing. When you are sitting still not doing anything the NC backs off the stroke on the pumps. When you move the control handle slightly the NC pressure changes and is sensed at the pump which changes the output. The more you more the handle the more stroke is applied to the pumps.