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Caterpillar "guts"

Discussion in 'Heavy Equipment & Pavement' started by bobcat_ron, Feb 13, 2008.

  1. bobcat_ron

    bobcat_ron LawnSite Fanatic
    Messages: 10,131

    I must have been really bored today, so I popped the cab up to see what and how Cat's "guts" are made of. Getting that cab up was easy, I only used one had, and it just kinda floats up like a cloud, Bobcat was a PITA, and you had to use both arms.

    Behold, the "guts":

    Fricken' huge hydraulic tank, Bobcat's is only 1/3 the size!!

    Neoprene spacers, 1 on top and 1 below, completely isolated from the chassis, a little more complex to remove the bolts, but better vibration control:


    Front view:

    Valve bank, it is indeed H/H controls:

    Main pumps:
    The big line coming off is the return, it uses a gravity flow for incoming oil, hence the odd shape of the tank:
    The drive hoses are on the right side, I followed them all the way to each opening in the sides of the chassis:

    The cab really tilts back far!

    All the hoses are clearly visible, no bolt heads sticking out that will cause damage to the hoses, there are some wires and plugs, but very few, and only running off the valve bank. I also took the liberty of using 3/16" nylon tie wraps around the hoses that I thought might be a problem, but there was only 1 hose that needed it, the rest are quite isolated from the other hoses.

    Now compare it with the Bobcat "jungle"


    Which one would be easier to inspect, clean and do preventative maintenance?
  2. ksss

    ksss LawnSite Fanatic
    Messages: 7,151

    A plastic hyd. tank? WTF? Plastic is prone to crack in cold conditions, and does not dissipate heat, but it is cheap. Nice touch looks like they stole a page from BC excavators on that one.
  3. Scag48

    Scag48 LawnSite Fanatic
    Messages: 6,067

    My guess for the choice on plastic was for less weight and corrosion resistance.
  4. ksss

    ksss LawnSite Fanatic
    Messages: 7,151

    Hyd tanks typically are not a source of corrosion, but the weight could be a factor. I think more likely they needed to create a container to match the space available. Plastic is easier to do that with than steel. It just does not have favorable heat transfer characteristics and they get brittle and are more prone to leak. They also are known to collapse.
  5. iron peddler

    iron peddler LawnSite Member
    from midwest
    Messages: 184

    the swirl in the hyd tank is the key component, it prevents cavitation and cools the oil before it goes back through the system...material is not an issue on a hyd tank....location is more key when comes to cooling and vibration.
  6. bobcat_ron

    bobcat_ron LawnSite Fanatic
    Messages: 10,131

    Now what really stumps me is, I spent 2 hours with my head in this 247, and the burning question is; Is this hydraulic system closed loop or open loop?
    I know Bobcat's was closed circut, there was only 1 big line coming of the little hydraulic tank and only a 1/4" line going back in, this tank has 2 massive 1 3/4" lines going in and out.
  7. qps

    qps LawnSite Bronze Member
    from Indy
    Messages: 1,484

    Now your reaching KS;)
  8. cat2

    cat2 LawnSite Senior Member
    from Mi
    Messages: 891

    yea its a little better than the bobcat, but there are some hoses on there that will be a PITA. but you will have that with any machine. I need to get a pic of the Deere. we need a pic of a case and gehl. and compare all of them
  9. bobcat_ron

    bobcat_ron LawnSite Fanatic
    Messages: 10,131

    I took an open ended wrench and tried to get on all of the fittings, there ain't much room, but as long as you can crack them loose, they'll move, I've seen plenty of odd sizes of wrenches needed to get hoses off Bobcats, not to mention removing other parts to get to the hoses.
  10. CarterKraft

    CarterKraft LawnSite Senior Member
    Messages: 290

    The implement is Open loop, all oil flows from the center pump to the control valve and then out of the big rubber line straight into the tank.

    The drive circuit has a charge pump, the first pump, which pumps thorugh the fan motor (AC compressor on the B-series if equipped ) and then to the filter cooler and then finally the drive pump were it is regulated to charge pressure and the excess goes back to tank.

    As was said the tank is designed to aid in heat transfer and air extraction.

    the tank material is not a problem.

    The underhood shots of a C-series is eve cleaner.

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