I have a Komatsu PC50MR-2 that works fine until the hydraulic oil heats up and loses viscosity (after about 30 minutes of work). It has an aftermarket thumb that is not operating properly, which I believe must be contributing to the problem. Unfortunately my machine is in a remote area and I can't find anyone to help troubleshoot the issue. Not sure how to isolate the problem...any ideas, anyone? I've changed hydraulic oil and filters, didn't help.
Can you remove/unhook the thumb hydraulics completely and see if it cures it? Sounds like there's a relief valve or something letting oil by and heating it up. Is it actually setup for a thumb or are the aux hydraulics plumbed for a small hammer?
In what manner does the thumb not work properly? Are you losing hydraulic power throughout the machine? Do you know what temperature the hydraulic oil is getting too? Does your hydraulics make whining noises when it loses power? Does the hydraulic oil in the tank look foamy when this happens?........need a lot more info.
Thanks for your reply. The set-up is for thumb and hammer (switch on boom to convert from one to the other) It makes sense that it's a relief valve. How would determine/ identify the problem valve?
Thanks for your reply. The hydraulic whining noise is almost constant from start-up. That squishy sound that you get when air is in the system. The tank oil doesn't look foamy. Not sure what temp the oil is getting to, but you can smell and feel it is hotter than normal. The thumb opens but doesn't close. When I try to close it, there is definitely more hydraulic whine
Does The switch control feed to the implement only or does it also control flow direction?
This I'm not sure of. There is an aftermarket controller that was installed when the thumb/ hammer attachment was added. There are 2 lines coming off the main hydraulic system to supply this controller, and then lines running to other components/valves. I will probably have to take a pic of the configuration because of my lack of understanding of what controls what.
For the most part all thumbs are aftermarket. That make and model of machine can have a lot of issues with the hydraulic system that are very hard to troubleshoot. The thumb may or may not have something to do with the problem. Usually if it works at all it isn't the issue. As I recall the cab has to tip forward for access to the main control valve. Perhaps some photos of the valve and the plumbing for the thumb would help. Basically you need an experience technician to have a look at the machine and clearly describe how it is set up and what exactly the problem is?
Did it ever run right?
Yes. It worked great when I bought it. Trouble started about 100 hrs afterwards
I'll have to take some photos. The machine is in a remote area and I'm having trouble finding a tech that can look at it.