Swing cylinder rebuild

At work we have an old Kubota L2850 with a backhoe attachment made by Woods. When I first started working there,  the backhoe had its issues, such as slow swing movement from side to side, and a horrendous leak from the upper cylinder on the dipperstick. The upper cylinder was rebuilt about three weeks before this repair, so that took care of the leak there. The swing cylinder movement became worse, and eventually got to the point where unless you had the engine revved up really high, it would not move at all.  This is not good for the engine on the tractor nor is it good for the components of the backhoe that are still working ok.

When I examined the machine, I found that I could move the boom left and right by hand with almost no resistance.  Seeing as how there are check valves and so forth that make hydraulic components operate, this should not happen.  It was apparent that it is time for a cylinder rebuild.

What you need for this task:
-Hammer
-various large sockets
-torque wrench
-penetrating oil
-appropriate seal kit
-wrenches and ratchets
-floor jack (2 tons capacity or greater)

This is the bi-directional swing cylinder, meaning that it rides on the chrome shaft and uses a set of attached chains to pull itself to the left and right.  This is how the boom moves on the backhoe.  The first task is going to be removing the nuts that hold the chain to the actual boom. Seeing as this machine is older I soaked these in WD-40 first.

I am sorry for the poor picture quality here, but these are the nuts in question in the top photo.  Once these are removed, the chain is attached by a pin on the end of the cylinder body on the last link of the chain, as shown in the bottom picture.  A cotter pin is removed and then you can tap out the pin with a drift and hammer.  Remove the chain assembly and set it aside.

The chains should move somewhat freely, but these did not, so I soaked them in WD-40 and let them sit overnight.  Over time, they get caked up with dirt, dust, and other sorts of grime.  It also does not help that nobody on these "professional crews"  thinks to clean these machines off and grease them once in awhile.

 

 Just to the left of those hoses is a large bolt that holds the shaft in place.  You will have to move the stabilizer a little bit to access these bolts (one per side).  A floor jack will help with this task, if needed.

 





On the bottom is the impact wrench I tried to get the bolts out with.  On the top is my one inch impact wrench which I used because I wanted them out in a more timely fashion.  Sometimes I get tired of trying to make that half inch gun work, so when that happens I get out the big dog.

After removing the bolts from the shaft ends, and disconnecting the hoses that run into the cylinder body, I removed the swing cylinder with a little bit of effort.  I also set a drain pan under where the hoses are to catch oil coming out of them.  Finally I got the cylinder onto the bench and began disassembly, forgetting that there was oil in the cylinder still and making a huge mess in the process.



To disassemble the cylinder, remove the nuts at one end of the body and set aside, then remove the long bolts and set aside as well. Using a hammer, gently tap on one end of the cylinder body (you should be able to tell where it separates) until it comes out.  Remember that this is aluminum, and that it could crack, rendering it useless.  This is the time where you will want a catch pan for the oil that will come out all at once.  Or you can make a mess, like I did.

 

 

 

After tapping the other end of the body out, the shaft will come out with it. This white ring in the center of the shaft is the failure point.  Its job is to keep the oil from flowing all the way through the cylinder, creating two separate chambers that can be filled with oil and emptied of oil, which causes the movement of the cylinder.  In this case, the oil could fill the entire cylinder and move from side to side, which is why I could move the boom by hand.  This ring as shown is supposed to be one piece, not broken and worn.

 

 





 Open up your seal kit (in my case, Woods part number 37873) and make sure you have every seal in the package.  Using the operators manual, I took note of how many pieces were listed and placed them left and right side, and center.  The small "O" ring in the center is an extra part, so it is now in the spare parts bins, where it will probably stay forever.

In either end, you have a retaining seal on the outside and a wiper ring on the inside.  Pry out the wiper ring (blue hard rubber) and make note of its orientation.  It will be difficult to install the new one but I have found using a blunt tool to push the wiper into place helps.  Make sure to fully seat the wiper ring.  Using a pry tool, remove the retaining seal from its bore, again noting its orientation.  I have found using a socket that is about the same size as the seal and tapping it in with a hammer will seat it in the bore with minimal difficulty.  Also coating the new seals with clean hydraulic oil helps with installation as well. Do this on both ends.

On the inside of the cylinder end there are two "O" rings, one is round and one has flat sides.  Make note of where they go before removal and replace them in that same manner, again coating them with clean hydraulic oil to ease assembly. In this case, the flat sided "O" ring goes toward the outside, while the rounded one goes on towards the inside. These can be removed with a screwdriver but should be installed by hand.  They will stretch a little (a VERY little) and still retain their shape.

 

For some reason I do not have a picture of the center seals, but remove the remaining outer seal and the inner seal, again using a blunt instrument.  Again coat the new pieces in oil and reinstall. Like the "O" rings these will stretch a little bit and still retain their shape once installed.

 

Now you can reassemble the cylinder. After wiping down the shaft and making sure the cylinder body is free of old seal pieces or dirt on the inside, install one of the cylinder ends first onto the shaft, then onto the cylinder body tube.  This will take some effort so using a hammer and a large socket (one that fits over the shaft) drive the end into the body. Turn the cylinder over and drive in the other end.  Make note of where the hose connectors are, making sure one is on the top and the other on the bottom, opposite of each other.  Reinstall the long bolts and nuts, tightening them to 45 foot pounds of torque as mentioned in the service manual.  Reinstall the cylinder to the backhoe by first installing the bolts to the shaft ends, then connect the hoses.  You might have to move the cylinder position on the shaft to get it back in place and to line up the top and bottom hoses.  Lastly, reinstall the swing chains.  Make note of the holes in the link pins for cotter pin placement.  Test the machine and check for leaks.  If all went as it should have, there should be no leaks and smooth movement.

 

 

 

Ten things I am starting to HATE about being a fleet mechanic.

Like the title says and I am just going to get right to it.

1.) Asking me if I will work on your car.
 The answer is a resounding yes, but there is this sign that hangs in the shop I need you to read and fully understand, that reads as follows: WILL I WORK ON YOUR CAR? YES, I WILL.  THE PRICE IS $60 PER HOUR. IN GOD I TRUST, ALL OTHERS PAY CASH. I base my times on book times, just like the dealerships.  Also, this is not a negotiable price.  No trades, no bartering.

2.)Wanting to have a twenty minute conversation when a minute or two will do. I find this annoying because the more time some people spend talking about what needs to be done, the less time I am putting into a project.  I also find that when I am under a truck, some people think that this is the perfect time to get into a long conversation about what they feel needs to be a "priority".  News flash: it's not your name on my paycheck and until it is you do not decide what I am doing most of the time.  The boss tells me what to do, kind of like he tells you what to do.

3.)Stupid statements like "When I worked at muckety muck two trolls Yugo Restorations LLC INC and some other letters this is how WE did it."
  Do us all a favor and go back.  I might have found your statement interesting the first couple of times you said it.  I might have even considered it.  About the tenth time frankly I am sick of it.  Besides, when is the last time you saw a Yugo?

4.)Asking me to borrow my tools.
  If I do not know exactly who you are, it's NO. No means NO. You have to understand, or refuse to understand, that the tool you want to borrow is how I make my living.  If I don't have tools, I have no way to make money.  I also would like to point out that there are no cheap Walmart tools in my box.  The LEAST expensive of them are NAPA tools.  The vast majority of them come out of my pocket, not the company's pocket.  Also, don't be that dick that opens up the box to see what is in there or just decides that you are going to borrow something without permission.  The standing policy is, as told directly to the company president: "I do not care WHO you are, whose FRIEND you are, who you are RELATED to that works here, I don't care if you have a signed permission slip from GOD ALMIGHTY. You take my stuff that is called THEFT".  Due to the value of the tools it could be considered (and you could be charged with) GRAND LARCENY, a FELONY.  You will most likely do serious JAIL TIME. It's not worth it to not ask, especially since I have rarely said no to anyone.

5.)When are you going to fix (insert some broken piece of shit here).
  Frankly, when I get the parts I need and get around to it.  See list item #2.  If you prove to be particularly irritating about it, trust me I will clean public toilets before fixing that thing you probably broke because you had a dumbass attack.

6.) Telling me how to do my job.
  This is geared more towards the crowd that is mentioned in list item #3.  The example is the same people keep breaking the dump cable on one particular truck, and these people feel that we should go over to some switch set up. (The technical term is bi-directional hydraulic actuator assembly and the industry term is electric over hydraulic set up.)  This takes money, which with parts has never really been argued, and TIME, which I have little to spare.  If you want something to work right, use it properly.  Besides, I am convinced that you will break the switch too.  Do me a favor and let me fix it as it sits without making it into some long drawn out project. This brings us to...

7.)STOP ABUSING THE EQUIPMENT.
  Abuse takes on many forms. This being said the two things I see most are not using the equipment properly and failure as an operator to check it and maintain it.  A one minute walk around would save lots of time as aggravation, as you might see that rim that is about to fall off or that flat tire.

8.)Know what is expected of you.
  Recently we had a truck stopped for a laundry list of items wrong with it, including no inspection certificate (locals call them "inspection stickers").  When this happened, the driver, who advertises themselves as a commercial driver with years of experience, calls me on my phone thinking that I can go out there and magically make the problems go away. The reality is, I cannot do that. I didn't take the call because if I don't know the number, I just wont answer in most cases.  My job is to repair and maintain the vehicle, including prepping it for, but not conducting, the inspection.  The Department of Transportation clearly states that pre trip inspections and reporting defects is the responsibility of the driver of the vehicle.  This includes checking the fluids and tires and making sure nothing is about to fall off.

  As an addendum to this portion of this list, I already grease the trucks and other yard equipment, I listen to your complaints and write them down on a list that never ever ends, and when the driver messes something up it's usually ME that gets the wrath of shit that comes along with it.  I typically work upwards of 65 hours per week over five or six days, and I make NO OVERTIME at that.  I am apparently on call every. single. day. Since my service truck is a piece of shit with no inspection, I used to use my personal truck to get the job done, but after watching the boss' friend and his son fuel up out of the on site fuel tank, yeah that does not happen anymore.  I have to schedule all vehicle services be they on or off site, and I have to work around some of the worst people when it comes to communicating with each other.  I am usually one of the first people there in the morning, and usually one of the last people that gets to go home.  Seriously, stop whining about what is expected of YOU.

9.)Stop standing over me.
  When I am working on something, no matter what it is, I do not need you standing there watching my every move.  When you insist on doing this, you do so at your own peril.  This is especially true when I am welding, grinding, using any power tools, or just turning a wrench.  My rule of thumb is that if I swing my arm out with whatever tool in my hand, and I can touch you, you are too close. 
I will also on rare occasions need to get out of the way of the falling machine or the fire that just started, and if you are in the way, you are going along for the ride.

 Think of it this way: when you take your car in for service that service station sure as hell will NOT allow you to stand in the repair bay watching the mechanics every move.  There are insurance regulations and laws that say you cannot do that.  I am not trying to be mean here, I just don't want you getting hurt because you were watching me weld something or sharpen something, and flying metal shit gets in your eyes.  At the very least, wear personal protective equipment that YOU provide.

10.)Let me do the job I was hired to do.
  When I was hired into the position of mechanic, I was tasked with keeping the (somewhat beat up) fleet working.  This means I have to service the trucks in a timely manner, correct the previous screw ups, be they by manufacturer or previous mechanic, order parts and run around like a headless chicken.  This is not exactly a fun job, but it is a job.  It is MY job.
 You, the layperson, do not generally get any say in what happens and when.  You do not get to tell me how to do my job, and you do not get to complain about how long it takes.  When I do a time quote, it is generally quoted a couple hours over what it actually takes, and this is because whenever I am under something, someone feels the need to call with some so called emergency that ends up being nothing by the time I get there.