11-06-2011 10:20 AM
Hello, we have and 330C DKY excavator with a a little noise sound in the hydraulic pump, and this sound increment in a very high noise when the machine works with boom, stick and in less manner with bucket, swing and one side travel. Only do not increment sound with the other side travel. The pressures, in the display monitor, before this situation occurs was Pump #2= 4900 kPa, Pump #3= 3800 kPa. Now the pressures are Pump #2=11000 kPa and Pump #3=3800 kPa. The technician tell us that the problems are in the valve pump control, but we d'ont believe that and we thing that the problems are int the main control valve. Any suggestions we will apprecciate. Thanks ...
11-28-2011 09:06 PM
if you check in the operators manual there is a procedure to evacuate the air in the hydraulic pumps. if there is air and the problem persists, there have been instances where the hydraulic fan pump, on the front of the engine , is leaking and the pump is sucking in air from the engine. can also look at the sight glass and check for bubbles in the oil. if you check the pressure with a pressure gauge the gauge will be erratic. you may need to contact your cat dealer for further repair.
11-11-2012 09:26 PM
seen this problem before have found that the fan pump, mounted on the backside of the engine front cover, is sucking air. check for air bubbles in the hydraulic tank. also if you look in your manual there is a procedure to remove air from the pumps. if you haven't had to add oil than there should be no reason for air unless it is being sucked in from somewhere. the conditon would be noticed on one side more than the other because the pumps are mounted none on top of the other, air goes to the top pump.