Vtgreg
Member
The machine is a Hitachi EX 100M–3 excavator. I believe it came from the factory with controls for an auxiliary claw or hammer. The four spool control valve is fully populated. Meaning a spool for the auxiliary, bucket, arm, and boom. There is a pilot function from position SK on the control valve, to the solenoid valve assembly. The cab has a pilot controlled foot pedal, and a electric switch on the left arm rest. The writing on the switch is in Japanese, but I believe left position is Bucket right position is hammer. I bought this machine used about five years ago. Problem: The machine would occasionally bog down for no reason. Dr. X software showed a possible directional valve issue. Replace the valve no difference. This bog down issue might go months at a time before reoccurring again. I’m sure everybody is thinking it’s a fuel issue. Don’t believe so, already replaced all fuel and filters. If it was a fuel issue it would be more consistent. during one such bogging down event, I put my arm out the cab window onto the hydraulic line for the auxiliary hammer or claw. It was hot! The two hydraulic lines for the auxiliary, supply and return we’re both hot. Mind you there is no auxiliary hammer or claw attached! There is however a crossover from supply to return on the boom. I’m not quite sure why that crossover is there. Using a hammer or claw would defeat its purpose. Meaning hydraulic fluid would go from supply to return bypassing the auxiliary. I have Numerous repair manuals for this machine, but not one identifies the actual components that are used for the auxiliary circuit. Nor have I been able to find An accurate electrical diagram schematic. On the solenoid valve body, there are proportional valves and a brake valve. However I do not know how they are controlled hopefully somebody can suggest a schematic to me. See the attached drawings. When the thermal images were taken the machine was in Vermont, ambient temperature about 25° F. Machine was only run about 20 minutes. 16 for hydraulic preheat, and four minutes operating the boom and arm. The Second and third show the crossover on the boom. Fourth pic shows the outer hydraulic lines. These are for the auxiliary. sketch is a diagram of the control for the auxiliary. Notice ambient temp is about 22° F, while the crossover and outer lines are in the 90s!. This should actually be close to 22 F, as this function should be off. On my sketch you’ll see that the lower port of the control valve is closed while the top port goes down the boom, through the crossover, through the manual direction valve, and returns to the tank. Also,note the two position foot Pedal, controls position forward and backwards, is in the middle neutral position. Moving it slightly forward machine bogs slightly, moving it slightly rearward machine bogs heavily. I don’t understand this as the top port essentially goes directly to the hydraulic tank, pressing the footpedal should have no effect. The electric switch on the left hand rest also has no effect. please anybody have a schematic for the switch? (Ed at toolking, this is the same machine we were talking about.) Anybody have a clue why it appears the auxiliaries are being used? What would the effect be if I removed the electric signal control to the pilot port on the solenoid valve assembly? Also what about switching the directional control valve from position CD to AB? (These are the only two options for this directional control valve.) I’m also wondering if there is a problem with the spool for this auxiliary. Wondering if it’s partially opened, hence, allowing fluid flow through the auxiliary lines. Please note I travel to a job site that has zero cell and Internet service. So it may take me two or three days to comment back. Thank you Greg. .
Third pic
Third pic