Bucket truck hydralic problem

Discussion in 'Shop Talk' started by poppy, Oct 30, 2005.

  1. poppy

    poppy Guest

    My brother bought a used Ford bucket truck to do some tree work. About a week ago the lift started freezing up occasionally. It seems to be always at the same angle when it stops. After it sets a day or 2 it will work again, but just until it reaches that same angle, then it stops again. It works fine either up or down once it gets past that angle. We looked for a hydralic line that might be binding at that angle but didn't find any. Any ideas?
  2. Beeman

    Beeman Well-Known Member

    Dec 28, 2002
    East TN
    Possibly the pins where the joints of the arm pivot?

  3. agmantoo

    agmantoo agmantoo Supporter

    May 22, 2003
    Zone 7
    Look for a nearly clogged hydraulic filter. You are using the fluid that is available initially and then something is occurring to get fluid from another source/area. The return hydraulic fluid from the off side of the cylinders is probably returning to the reservoir to give the second lift. You may just have a low level of hydraulic fluid in the reservoir. Reply with what you find.
  4. rambler

    rambler Well-Known Member Supporter

    Jan 20, 2004
    Good advise so far. New filter would be my first guess if you don't see any binding or hose issues. Look at the oil, if replacing the filter, might want to get good new oil too.

  5. moopups

    moopups In Remembrance

    May 12, 2002
    In beautiful downtown Sticks, near Belleview, Fl.
    There is a strong possibability that the plunger/piston meets some type of rust or pitting within the cylinder at the point of resistance, exstend the cylinders and check with a straight edge for a bent shaft.
  6. farminghandyman

    farminghandyman Well-Known Member Supporter

    Mar 4, 2005
    lubricate,(grease) all the moving parts the pins and fittings,

    a pin or joint may be binding up,

    check for dings in the hydraulic cylinders, or a ding in the rod of a cylinder, even a very small ding can cause interference on the system,

    since you can go past at times my guess is you hydraulic fluid level is ok but I would check, and replacing or cleaning the filter is a good thing, but would doubt that that is the cause,

    depending on the size of hose and some other factors you may be plugging some orifice with some dirt that is floating back and for forth in a line,

    most man lift devices have restricting orifices in the cylinders to slow the decent if the system fails so you don't crash, to the ground.

    the other possibles they may be a holding valve in the lines, that take pressure to open and that is so the cylinder needs to be under power to move, (safety), and if it, is malfunctioning, but to stop in one location I would not think so, unless there is some dirt in the system that is floating back and forth with in a hose that is "trapped" in that hose, and moves with the fluid,
  7. michiganfarmer

    michiganfarmer Max Supporter

    Oct 15, 2005
    Near Traverse City Michigan
    I would disconnect the cylinder, and move the arm manually. see if it binds up with no cylinder attached. That will tell you if its the hinge pins, something int he arm, or the cylinder. what confuses me is that it will work fine after it sits unused for a while. that would lead me to think it might be a bent cylinder rod