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Another Central Hydraulics Thread...

Discussion in 'Truck & Equipment Repair' started by Crestview, Oct 22, 2010.

  1. Crestview

    Crestview Junior Member
    Messages: 29

    Hey,
    I just bought a 95 F-350 7.3 dump with 8.5 western, stainless spreader and central hydraulics. I haven't run the spreader yet because the previous owner did some work in the rear and I can't get onto the fittings till I do some plumbing. The dump also runs off the central. When I throw the switch, I get a lot of noise out of the spreader controls, even though I'm pretty sure they're turned off. I never used one so I don't know much. Should I be getting noise out of those?
    Also, what is max RPM for central hydraulics when it's engaged? Just curious, and any other tips you might want to throw my way, please feel free!!

    Thanks a lot!!!
    :mechanic:
     
  2. john mc

    john mc Member
    Messages: 70

    my old hydraulic spreader control made noise i think they all do. you could be hearing the returns. wait till the chain jams up and the noises you hear then.as for the central hydraulics rpms. mine is on all the time and i run down the hi way at 55 mph .no problem. but mine is not a f350.
     
  3. LON

    LON Senior Member
    Messages: 749

    does it sound like a mouse squealing? If so your valve is on and it's blowing over relief. It is normal to hear the sound of oil flowing.
    Have 30yrs experience w/ central hydraulic systems so if you have any questions give me a shout.
     
  4. LON

    LON Senior Member
    Messages: 749

    I'm in the shop today if you'd like to call. Find me through my signature below.
     
  5. Crestview

    Crestview Junior Member
    Messages: 29

    Hmmm... I tried flipping the on/off valve and the noise went away! Apparently it was always on. Who'da thunk?
    One of the spinner controls won't turn so I may have to rip it apart, I'll definitely be looking to bring it somewhere to get checked out soon!!
     
  6. LON

    LON Senior Member
    Messages: 749

    sticking knobs come from someone turning the knob down to zero while the spreader control valve is still warm. The aluminum block will shrink back down and seat tight on the end of the spool. After taking the screw out you can pop the knob up off using 2 good sized screwdrivers on either side of the knob. Gently work the knob up off. Use a pair of pliers to turn the spool open a turn or two. Now turn the spool back down to "zero" with your fingers (this is so you don't seat the spool to hard). When you set the knob back on make sure the internal stop in the knob is to the right of the spring loaded pin. You should now be able to turn it & count all 10 or 11 clicks.
     
  7. Crestview

    Crestview Junior Member
    Messages: 29

    Ok, before I do that I want to find out some other stuff here. I mentioned that I flipped the on/off valve and found out it had been on. The previous owner mentioned that he never used the salt spreader. I'm willing to bet the valve was "on" for the entire time he had the truck. The fittings were capped. Worst case scenario is he drove the truck to plow, dump and everything else while flowing fluid to the capped fittings, thereby blowing through the relief valving in the control module for the spreader. If this worst case scenario did occur, what is the chance there is damage to the control module?
     
  8. LON

    LON Senior Member
    Messages: 749

    probably none. I've seen them hot enough to melt the plastic caps & down through vinyl flooring and still work. That much back pressure is harder on the clutch pump than it is on the valve. I would change the hydraulic oil as it is probably broke down. We use only Agip ISO/AW 15 hydraulic oil.