Hi all, Experiencing creep on boom when leaver is in neutral, get worse as it gets warm. I've isolated the boom and it is not there piston seals, i have also swapped ARVs problem still occurring. Can anybody give me some advice on how to rectify this problem. Thank you in advance Jack
Hello red..... can you explain how you isolated the boom cylinders? No offense, just double-checking. I'm not familiar with the EK60, it's possible there are check valves in the spool section that might be worn, sometimes they're in the port relief valves, sometimes not. Could be a worn valve spool, or possibly a centering spring is not returning the spool to exact neutral but that's a long shot. Not a lot else to go wrong unless it's fitted with some extra valving, cushion valves maybe?
I was thinking the same thing... just how did you isolate cylinders .....Normally a cylinder that leaks down ,same as creeps produces heat and after operating for a few hours the cylinder that's bad is way hotter then any of the others ..easy way to check this is a laser tempture gun
Good day I suggest you rest the bucket on the ground - dispel residual pressure plug one cylinder positive dive start the machine and cast the arm out - reverse the procedure then test for the remaining cylinder. You can also try raising the undercarriage to test if the seals bypass. You may find this animation helpful. http://youtu.be/0PSHGL_ObG0 Kind reagrds Uffex
Hitachi EX60-5 Boom seal check Oil warm Fully loaded bucket on ground, dipper vertical engine off, release tank pressure undo boom up pipe near cylinder. Place ball bearing in pipe connect pipes. Line is now blocked push dipper out, bucket is now in the air. Boom did not creep so piston seals are ok. So problem must be in value block. .....thoughts. .... Regards, Jack.
Niceeeeeeeeeeeeeeee
wrong. since the volume of the barrel end of the cylinder is greater than the volume of the rod end, you cannot displace the barrel end oil into the rod end. there is simply no room for it. To test the piston seals, place the bucket on the ground,remove the hose from the rod end (and cap it) and lightly raise the boom. Let go of the lever....and as you watch the bucket creep back down to the ground(and the displaced oil from the barrel end of the cylinder pours out of the open fitting into the bucket you placed under it),call the local seal supplier and get yourself a new seal kit for the cylinder.
He meant cap the hose, just for clarification. And he's right to a point. If the piston seals ARE leaking then pressure will equalize on both ports and whichever port relief is weak or leaky will allow the oil to pass on to tank, even if you switch them. The fact that the boom didn't creep down with the butt end hose blocked doesn't actually prove the piston seals are good, but it does prove that when the boom leaks down the oil has to be going out through the butt end hose. So do the test as cutting edge suggests, if only just to completely rule out any possibility that it's piston seals. And if you don't have boom drop with the rod end hose disconnected and no oil comes out the open connection, then with the bucket on the ground and engine off again, swap the two hoses since you're already half way there. Could be a check poppet in the control valve, or as someone else suggested a pilot control issue. Pain in the butt but it's all part of diagnosing the problem.
Thank you for your replies, I shall try that procedure, Regards Jack.
Hi there Jack, id say its most likely your boom ram seals but do the checks as above to see what happens! one other check to do is check the servo valves under the lever to ensure they are returning properly, had this on a hitachi once! also the little servo valves can leak and may cause problems like this! What part of wales are you in? I have all the seal kits for Hitachis in stock if you need any! Aiden