this tractor runs very well and the direction control is very responsive. how ever the boom up works in the cold until it warms up good and in the hot months not well at all. If I roll the bucket down and lift the boom at the same time the boom will go to about 3 feet off the ground, then it will lift a 1000 lb bale of hay with ease. as it warms up we can slap the control back and forth and it will lift about an inch or less at a time until it reaches that 3 foot area then up it goes. thanx in advance for any help.
That sounds to be cylinder issue. Hot hydraulic fluid bypassing until a relative free of damage region is reached internally. Does the condition repeat at the same height every time when warm? If it does could be a ballooned section albeit minor in the cylinder tube or a score allowing fluid bypass creating a counter productive pressure rise on the evacuating side of the cylinder.
it stays where ever you put it with no leak off. will that make a difference?
Seals may be holding with no driving force but a score could bypass during a lift. Uncertain as to the design on the hydraulics you have may use a cross pressure relief block to allow lift/drop and to lock the cylinders when no demand rather than rely on the control valve system. Those take a feed from which ever side is in demand to release the other side hydraulics on the cylinder and could very well be within your valve body but not usually. Could be sticking, could have broken spring internally that depends on cylinder angle to allow to move, lots of alternate paths. Is Down direction ALWAYS OK? This is a simplistic schematic:
You will most likely need the hydraulics scheme for your particular machine and a decent shop manual to really get into it.
I bought the service manual but don't read hydraulic schematics very well at all as I don't know the symbols yet, studying them now View attachment upload_2017-8-16_16-59-6.png
is this what your talking about
That would be it. Takes lift oil pressure to open the spool and allow the draining side to do so or unlocks the cylinder. That would be a starting point to look into.
thank you very much if it gets to crazy looking I'll take it to a hydraulic shop. I gotta try first tho
Get anywhere with this machine??
kinda, I found a electric solenoid valve in the pilot control circuit for the boom. the dealer says it is a brake light switch. removed it and it worked very well for approx. 3 hrs, most work it has done at a time since I got it. then the same thing started to happen again, now it won't lift at all. I took the pump apart and one seal is torn up very bad the same seal on the other end of the pump is missing approx. 1.25" of it (completely gone). with no rebuild kit available I ordered a new pump.
thank you very much for your input. I found the valve that was shutting it off while studying where your pic showed and trying to follow the circuit. if new pump does not fix it I will be studying and asking some more. pump was putting out 475 lbs and should be 32-33 hundred
Sounds like it had a multitude of issues. Hope the pump fixes the final issue.