So I was wondering if anyone could help me with a problem Im having on a Bobcat 341 excavator 2004 model. When oil warms up the boom gets a little jumpy when you reach all the way out and try to just scrape the ground. I am a union operator and run other hoes during the day. Also other operators ran it and said same thing. I tested pilot pressure and it was around 225 idling and 400 wide open. Another thing I noticed is that when idling the machine will not raise the boom, swing left or right, and barely tracks. But if you raise above an idle as soon as pilot pressure hits high side they start moving like they should.. Funny thing is that it wont lift the empty bucket but will pick the machine off the ground idling pushing down on boom. Just curious on anyones thoughts on what this could be. When oil is cold maching will do everything normal. Its not just one cicuit its several.. All the manual control functions work fine. Could someone explain to me what these parts do so I can understand a little better for now and future troubleshooting? Thanks Crossport block Dual sequence valve Port relief valve Load check Build up valve Compensator Anti cavitation valve Thanks for any help, I really do appreciate it
Good day Robert That seems a big pressure loss if we are talking PSI, please see attached. Kind regards Uffex
thanks for the info. My service manual says idling pilot pressure is supposed to be 235 psi and full throttle is 435 psi. It seems pretty close to that. Everything operates fine until machine is warmed up. Then certain functions dont move at all or very fast at idle and boom is a little jumpy runny at full throttle. It will not raise the bucket off the ground idiling but will pick the machine up pushing down on the boom. I don't think the pilot is moving the spool. Wondering if it has excessive oil bypassing in joystick. But it also does it on slew left and right and travel left and right when idiling. Im just guessing but I think the manifold where I'm testing from is fine and pressure doesn't drop. But the joystick gets a supply line and a tank return with 4 ports going to controll valve and each of the 4 ports has a pressure reducing valve and if it was bypassing in joystick that might explain why pressure isn't dropping at manifold. So how would I verify this so Im not just throwing parts at it. Also if that is the case then that would mean the slew control joystick has same problem. Unless I m missing something.
Good day Robert I suggest you check out the main spool movement and then move on from that point. Kind regards Uffex