Cat 304.5 Broken bucket Piston Arm (pictures)

[HayBay]

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.

[Scag48]

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.

[dozerman21]

We're you prying or pounding?

[Dirty Water]

I'm going to go with prying.

[Gravel Rat]

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:

[Tigerotor77W]

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

[HayBay]

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.

[Gravel Rat]

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.

[gammon landscaping]

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.

[Construct'O]

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

[waltero]

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.

I believe that this is probably the reason, been there myself so I have some experience with breaking stuff. I ended up paying about $500.00 to get mine fixed.

Walter

[RockSet N' Grade]

as far as what to do now.......i would suggest getting a whole new cylinder set up vs. just a new rod. the price difference is not that substantial, you will be assured of up time and not redoing this whole thing again. as far as being faulty, maybe it was, but after 3000 hours, you don't have much of a leg to stand on.........that's pretty good life. at 3,000 hours I would give your hoses a good visual to see if any are starting to weep and if so consider replacing them when you replace the cylinder.

[HayBay]

When I was pulling that cylinder off the bolts looked kinda new and there was teflon tape that looked brand new on the top Nut holding the bushing in. What I am saying is I don't know if the cylinder is 3000 hours old.

Here is the twist to the story.

I am just Demoing this Machine its not mine ;) . Will I be paying this out of my own pocket? I do have Rental Insurance Damage with this company through my Insurance company but I don't know if this falls under that catagory. Or is it even worth while to go through insurance because of the minimum deductible.

Thanks for all the info guys.

[hosejockey2002]

I am just Demoing this Machine its not mine . Will I be paying this out of my own pocket? I do have Rental Insurance Damage with this company through my Insurance company but I don't know if this falls under that catagory. Or is it even worth while to go through insurance because of the minimum deductible.

I'll say that's a twist. You could just call them and say "no thanks, I don't want to buy this machine because it's got a broken cylinder" and see what they say.:dizzy:

[Gravel Rat]

Ding ding ding we have your answer already :laugh:

I thought you owned the machine since new if its a used machine that your trying out who knows what has been done to the machine. Its probably been beat the h*ll out of. I don't think I would be buying that machine it sounds like its been abused. Be very leary of new paint and power washed parts somebody is trying to cover things up.


Good Luck

[tallrick]

I have seen this before. Case hardened rods don't like being bent in any direction. The hardened outer surface probably had cracks from all the previous use. Usually only Magnafluxing can spot the problems. My understanding was that the mini-ex hydraulic pressure would not be high enough to cause failure, but things do happen. Leveraging the bucket on the ground is definately a no-no. I would be reluctant to spend a lot of $$$$ on a reman or used rod. Best bet to locate new, if posible. I have used surplus parts on older machines, with good results.

[gammon landscaping]

it was a demo.....i will go out on a limb here and say the mini is plumbed. and i would say it probabbly has had a hammer on. the hammers are hard on mini's and the bucket cylinder takes alot of abuse, my rental company gives operating guide lines when you rent one with a hammer. one of there notes is that always keep the cylinders between 1/4 out and 3/4 out. the girl at the desk told me they replace bucket cylinders about every 1000 hours on the big excavators

[dirthog]

If you look at the top of the rod it looks rough if it was bent even a little it will scuff on the inside of the packing gland and lead to breaking. would bet that someone hauled the machine with the bucket curled closed and down on the tube of the cylinder the bouncing of the arm will cause the rod to flex and fail. We have machines out with thousands of hours with and with out hammers and very few problems and some with almsot no hours and the same problems look at the tube and see how badly it is beat up on the top. another thing that is hard on the rod is letting the bucket hit the ground taking it off the trailer.