334 diagnostic challenge, first time poster

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bobcat334murrieta

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Aug 15, 2020
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Hello All i have a 2004 334 mini x, im a seasoned mechanic and not afraid to buy testing equipment for this job as recommended. She has 3500 hours. working flawlessly, well maintained, quiet motor, new tracks and oil leaks always fixed asap. Used it hard all day then parked it and the next day went to use her and the travel was almost nothing, but the swing and arm functions would work seemingly full strength. interesting that if i was to raise or lower the backfill blade while trying to travel, i could travel at about 50% of normal speed (but only while i moved the back fill blade up and down, even a small amount) my guess is a pressure valve/relief is stuck open. cant imagine a pump would work perfect one day and the next day is bad. if so i dont know which one and where it would be. just some more back story to my machine. i rebuilt the rotary valve (the part at the very center of the unit with all the hoses)--it had a leak (about a year ago) then replaced a few travel hoses on one side (had a hose leak) it was very dirty in the area and pulling the new hoses through the lower frame but I was anal about how clean i was but you never know if i got a little debris in there. i even flushed the hoses right before connecting them and had the AN ports capped during the pressure washing process. that was about 6 months ago. lastly i had a weird issue about a month or so ago where one of the travel levers was stuck like i could not move it (if i recall it was one direction on one handle only). i dont think it was a cable, after mildly moving it back and forth it finally got free and exhibited no other issues or side effects until now. i tell you this because maybe it might add to the diagnosis. I have a manual but would like some seasoned answers as to what area or where i can jump in with two feet. perhaps there is some valve that can get stuck causing these exact conditions. John from Murrieta Ca
 
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bobcat334murrieta

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Aug 15, 2020
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more info got a pressure gauge, pressure build up is on the money at 600psi bucket and dipper pressures are great at 2900 back fill blade hits 3400 in both directions slew pressure is 2600psi in both directions boom offset is low at 1000 should be 2650 psi. boom moves slowly in both directions. if i move the back fill blade at same time pressure goes to 2000 and boom moves normal right and left travel motors only produce 1000psi too but also go up to 2000 when the back fill blade is being moved at any amount any ideas?
 

Tazza

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more info got a pressure gauge, pressure build up is on the money at 600psi bucket and dipper pressures are great at 2900 back fill blade hits 3400 in both directions slew pressure is 2600psi in both directions boom offset is low at 1000 should be 2650 psi. boom moves slowly in both directions. if i move the back fill blade at same time pressure goes to 2000 and boom moves normal right and left travel motors only produce 1000psi too but also go up to 2000 when the back fill blade is being moved at any amount any ideas?
I like your thinking about the relief valves, i'd start there too.
No idea if your machine is the same sort of setup as mine, it has 3 hydraulic pumps, all with different relief valves, the manual gives the figures of what the pressu re should be,
You mentioned that the travel motor control lever was sticking, i guess it's possible there is an issue with the control valve.
 
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