Hello all, I recently resurrected a late 80's pc220-5 serial number 35321. Machine has a magnet on it for most of its life, so i had to find a bucket cyl to make it a digger again. I found a used cylinder off of a pc200 and put that on it. I'm having some issues that i can not figure out, maybe someone has some input! Here is a list of things I have done already: cleaned out fuel tank, new fuel lines, new filter, new hyd filters, new air filters, new chains, new rollers, new(used) bucket cylinder with new packings, new(used bucket), h bracket. Issue 1: Machine starts and idles great. When i turn throttle up, it will rev right up and run great. When I attempt to move either direction, or use the boom/stick (up and out) machine will start to putter out and stall if i stay holding the joysticks(tends to stall more when the cylinders are almost all the way retracted) . The machine does NOT stall when i use the boom to lift the tracks off the ground (it will lift either side as high as it can go), and when either side is lifted, i am able to track the machine without it stalling at all (spins either direction great). Lots of white smoke, which led me to believe it was a fuel issue, so I drained tank, cleaned it spotless, put new rubber line on, removed injector lines, made sure they were clean, turned it over with lines off to make sure fuel was pumping out of injecter pump, new filter, this did not make a difference. I'm starting to pull my hair out! Issue 2: I cannot get the new bucket cylinder to extend or retract all the way. If i rev the machine all the way up, and hold the joystick out (as to curl the bucket all the way open), it will start to go and then basically "hit a wall" and veryyyy slowly open almost all the way then stop. Basically like its struggling. Bucket will curl closed at almost normal speed, but if i attempt to dig it has ZERO power, will not even attempt to dig. Just kinda hit the ground and machine does nothing. If anyone can help i would really appreciate it! thanks in advance!
Is there an "A" to start with on that serial number? If not, then you have a gray market machine. Do you know about the wire strainer in the suction side of the hand priming pump for the fuel? Do you know how to get to the diagnostics of the machine. Here is a video that shows how the diagnostics work. The machine in the video is a PC400 but the electronics are the same.
Machines with magnets don’t use the bucket circuit at all. It has probably been blocked out, turned down, or restricted in some way.
I'm no help w/ the hydros but as John said> theres a strainer in the banjo bolt directly under/below the hand primer.. THAT gets clogged w/ "stuff" & will starve the system of fuel.. THATS the easiest thing to check.. Good luck.
Thanks for the reply’s. I did not know about the digital read outs, thank you! When I start it and idle it it read blinks with 24 then s2 then 09. And the other screen shows a solid green dot. What and where should I check from problems? Thanks !!
The 24 code is the rear pump pressure sensor. As I recall it is on top of the main control valve next to the front pump pressure sensor. Have you checked for the strainer?
Success! Ok found the strainer. It’s was full of crap. Cleaned and put back together. That solved the majority of the issues. Now it moves without stalling. Bucket cylinder still won’t work correctly. Anyone know how to adjust it. Maybe it was backed off due to the magnet being in it since it was new?
There is no adjustment for it. If it moves at all it means the hydraulics are sending oil to it. The fact that it only moves a little would tell me there is something wrong with the cylinder. That might be scary in that a bad cylinder might be contaminating your hydraulic system. At least pull the rod and piston assembly and look down the barrel for damage or other issues.
I have already had the cylinder apart. It was leaking so I took the rod out and replaced all the seals and packings. There was some minor pitting at the end of the cylinder but I honed it out and put it all back together with no leaks now. After I cleaned the small strainer out and ran the machine the "24" code went away. I then parked it for a few minutes and shut it down. Went to start again and the code is back. Could that have something to do with the bucket cyl. not working right?
That means you likely have a wire loose at the sensor or the sensor is intermittent. What the sensor does is let the computer know the pressure when you are in high speed travel. When the pressure reaches a certain point the computer shifts the travel mode back to low until the pressure comes down again. Can you trace the piping back from the bucket cylinder and look for other components that might have been installed between the cylinder the main control valve. If nothing is there, I would probably start tracing the pilot hoses that shift the spool back to the shuttle valves and then to the joy sticks. Which joy stick is running the bucket now?
I can trace them back and everything looks like it stock and never been messed with. The right hand joystick is controlling the bucket. Which spools or valves can I take apart and check first ?
I would probably check the spool first and then check the pressures on all the functions. Pilot pressure should be about 426 PSI at the pump. Do you know how they powered the magnet? Sometimes a function like the bucket can be used to run something else. I suppose they could have put different relief valve cartridges in to run a motor but that usually would only be in one direction. They also could have put a spacer at the end of the spool on one side so it doesn't make a motor run backward.
The lines for bucket were blocked off right where the rubber hoses would be from the machine to the boom. Magnet was all electronic
The electricity to run the magnet had to be generated from somewhere. All that I have seen and worked on had a genset on the machine driven by the hydraulic system.
There was a big electric motor mounted on top of machine with a SERP belt that ran off the motor of the machine
I’m not saying your wrong because I’m not positive about most of this stuff but I think the genset was all run off that electric motor that was powered by the crank of the motor
I just tried swapping hoses under the cab for the joysticks. When I swap the hoses, the bucket still didn’t work right, and it was just a different motion of the joystick. I then took the hose off the end of the bucket cylinder and ran the machine. I had heavy flow from that hose. I was under the impression I should not be getting flow from that side ???
Lots of flow from the circled line when machine is just idling and joysticks are not being moved. I then blocked off where it is circled and “opened” the bucket and this is the only time I’ve ever been able to fully open the bucket. Still didn’t seem like it opened fast enough though.
You will always get some flow on an open line. I'm not there to look over the machine so I suggest you get someone local to help you from here. Good Luck!
I believe that pipe you circled is for the aux circuit? If you un capped that and you had flow that means your aux circuit is being actuated when you haven’t told it to. And as far as pulling the hose off the bucket cyl you’ll have a lot of oil in the lines but you shouldn’t have a pressured flow of oil continuously. I would check your pilot pressures going into your valve spools and see if they’re actuated when you move your joy sticks. Should have around 500 psi
So I’ve come a long way. Talked to Komatsu and realized that the Bucket cylinder ports were just plugged, I had to buy 2 new “cartridges” as the dealer called them and install them where the plugs were. Now everything works. Finally got to go out and use machine tonight. Now I have a new issue....all the functions work, but nothing seems to be working at full power (even in the highest output setting on the monitor). Doesn’t seem to have the right amount of power for digging and it won’t even spin the tracks any direction besides perfectly forward or reverse. (Ie I cannot spin machine 360 while sitting in very loose topsoil). Engine doesn’t seem to be struggling for power. Just seems like hydraulics are lacking power. Any ideas ??
Your cut outs are set too low. You need a hydraulic tuneup.
If you had the komatsu test port adapter and pressure gauge you could stall some functions and see what your reliefs are set at.
Okay I will do that today. Does anyone know what the purpose of the hydraulic hose is that comes off the top of the pump and is routed down and dead ends? Basically a hose that goes to no where? I blew that hose. Don’t understand why there is a hose to no place. Thanks
The hoses with dead ends are snubbers to dissipate the hydraulic spikes that happen. If they are leaking you should replace them with Komatsu hoses as will fits for a supplier will not stand up to the hammering that those hoses take. The cutout functions are not controlled in the relief valves. They are adjusted on the pumps and you will need someone who knows what they are doing to adjust those.
So i got gauges and checked the pressures on the main pump of all the functions. I have 4000+ PSI on everything except bucket curl function. So i swapped relief valves and the problem moved with the valve. Does anyone know where I could find one of these valves other than having to go to the dealer and pay $500. I believe the part number from the dealer is kac-709-70-71102 Also I've been able to use the machine but It still does not seem to have nearly the "balls" it should I replaced the rotary manifold seals (they were completely broken down and missing except a few pieces of the seals ) and I thought that would fix my issues, but the machine still struggles. Tracks have little to no power, I have almost zero power trying to use the bucket to push side to side, and it will not do more than 1 function at a time without struggling. Engine RPMS never change, just hydraulics dont work right.
The bucket curl function is usually at a lower pressure than boom and stick. Boom and stick are usually set at 4,600 PSI. I don't remember the bucket setting. The swing functions is usually set at around 3,800 PSI. Travel settings usually have a function called cut out cancel and that bumps the travel settings to 4,900 PSI. If you are getting those kinds of pressures on the main and circuit reliefs, then your problem is on the pumps. Again, that is the cut out function which needs to be turned up. If it can't be changed, then you have a pump problem. I have a calibration video in the works for Komatsu Dash 5 excavators but it will be some time before I have it finished. Calibrating the pump though is not something I would recommend a novice mechanic or an operator perform. You need someone who knows how the system works and can interpret what the pressure readings mean and adjust accordingly. You have a very old machine. There will be lots wrong with it and it will cost you to fix them. It will cost you lots more for hit and miss on suggestions from people here who can't be there on site, see the machine and hear how it runs.