Cat 304.5 Broken bucket Piston Arm (pictures)

Discussion in 'Heavy Equipment & Pavement' started by HayBay, Mar 23, 2007.

  1. HayBay

    HayBay LawnSite Senior Member
    from Ontario
    Posts: 846

    Just broke er.

    Ground is still partial frozen in some areas here. Top 6 inches.

    Is this defective or am i a putz.

    Its the Bucket cylinder.

    3000 hours on the machine.




  2. Scag48

    Scag48 LawnSite Fanatic
    Posts: 6,067

    Wow, 3,000 hours, I'm surprised the rest of the machine hasn't fallen apart! Seriously though, mini's just aren't built to last as long as fullsize excavators. I'd say you got pretty lucky getting 3,000 hours out of a bucket cylinder, 3,000 hours on a mini equates to about 9,000-10,000 hours on a full size machine in my book. Replace it and keep going.
  3. dozerman21

    dozerman21 LawnSite Bronze Member
    Posts: 1,170

    We're you prying or pounding?
  4. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799

    I'm going to go with prying.
  5. Gravel Rat

    Gravel Rat LawnSite Fanatic
    Posts: 9,544

    I never seen a cylinder do that it must have been a piston shaft that was faulty. Hydraulics get hot but not hot enough it removes the strength in the chrome shafting.

    I have a feeling you might have bent the tube aswell so you will need a whole new cylinder. The Cat dealer should have one or get you one probably looking at 2000 grand atleast. If the tube isn't bent a hydraulic shop can make a new shaft and weld a rod end on.

    I have been pulling wrenches for a few years I seen many cylinders bent from being hit or something jammed between it and the boom.

    Good Luck :canadaflag:
  6. Tigerotor77W

    Tigerotor77W LawnSite Bronze Member
    from Germany
    Posts: 1,891

    I'm curious, too, as to how it happened...
  7. HayBay

    HayBay LawnSite Senior Member
    from Ontario
    Posts: 846

    Was trenching with the machine, 3 feet deep and 16" wide. There was some frozen ground about 4-6 inches thick on top. I cleared out under the frost first with the bucket then with a clean bucket attempted to curl the bucket up to break the ground from underneath. First 200 feet of trench went well.

    I wonder about the flaw you can see in the piston, if that made it weaker at that spot.

    I am pretty sure the piston was almost fully extended when it bent and broke. Hopefully the cylinder is ok.
  8. Gravel Rat

    Gravel Rat LawnSite Fanatic
    Posts: 9,544

    If the barrel (tube) is fine then it should be a straight forward rebuild. Looking at the pictures there was a defect on the end of the plunger end of shaft.

    That Cat mini must have power if can do that kind of damage. Any mini I have ran usually powers out or the machine slides or rolls up on its nose.
  9. gammon landscaping

    gammon landscaping LawnSite Senior Member
    Posts: 550

    i would say no defect here or it would have happened before 3,000 hours. what probably happened here was that he was healing the bucket. this when your teeth are under a fixed object( frozen ground, a rock, stump, or anything that is to hard to dig) and the bottom of the bucket is on the ground and you are using the bucket to pry with. this is a no no. this puts alot of strain on the bucket and cylinder. and when it is fully extended like this one was they can break easy. when the plunger is at the end of the tube, you have a very small lever basicly and a long lever on the out side. makes it easy to break them.
  10. Construct'O

    Construct'O LawnSite Bronze Member
    from Sw Iowa
    Posts: 1,387

    Now thats what you call real breakout force:weightlifter:

    Might want to check your pressures out to be sure something hasn't changed there.I would check on the price of a cat reman cylinder, or reman rod.Not sure if you have to have a core or not.

    My dozer operator had the butt of a tree roll over behind the dozer blade on my dozer and trying to get it out raised the dozer and bent the rod in the cylinder.Reman rod and rebuild on the cyclinder was over $1500 dollars plus the down time.

    We cussed and discussed:hammerhead: what to do and not to do next time.Good luck

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