port block on bobcat

Discussion in 'Heavy Equipment & Pavement' started by R & R Yard Designs, Apr 3, 2010.

  1. R & R Yard Designs

    R & R Yard Designs LawnSite Senior Member
    Posts: 646

    Can you guys help me. My bobcat 643 keeps drifting down in the arms. I have gone through the rams and the valve and they are all good. Now before I go and take the pump out my friend has told me to check the port block filter the thing is where is and how to get to it
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  2. Nelson M Martin

    Nelson M Martin LawnSite Member
    from Ontario
    Posts: 192

    first take the lift cylinders off and make sure the nut (located inside cylinder)holding the piston onto the cylinder rod is tight
     
  3. R & R Yard Designs

    R & R Yard Designs LawnSite Senior Member
    Posts: 646

    I have had the tilt redone. Now the two lift had no blow by when I tested them with air in to the ports. It will lift somewhat ok with no load in the bucket but will not lift the tounge of an empty trailer up at all. I had the spools looked at and were oked. I hope its not the pump
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  4. 93turbo

    93turbo LawnSite Senior Member
    Posts: 482

    How much preasure did you check with 100lbs? thats not enough to tell anything compared to 3000lbs of hydraulic preasure
     
  5. R & R Yard Designs

    R & R Yard Designs LawnSite Senior Member
    Posts: 646

    Good point. We also took off the lift lines from the cylinders and hit the pedal to retract the rams some more and there was no blow by that we saw. So I don't know what else to do
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  6. 93turbo

    93turbo LawnSite Senior Member
    Posts: 482

    buy a 5000PSI guage and hook your lift lines together and T into the gauge and then try and lift. your gauge should go up to your releif preasure and if it does and you let off it should stay that high till you let the preasure off. If you do not have any preasure or very low preasure then you will have to troubleshoot farther and see if a hydraulic shop will hook up a flow meter to your pump
     
  7. freddyc

    freddyc LawnSite Senior Member
    Posts: 578

    did you pull out the pressure relief valve and make sure theres no debris in there?? Do you seem to have adequate pressure to the lift arms? If you time it from full down to full up, how long does it take ? You could have a small piece of junk in the relief valve, but if so, you should see some weaker hydro action, especially lifting heavy objects.
     

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