Anyone know an easier way to remove and replace a leaky boom cylinder on a BT 900 backhoe attachment on a L 35 Kubota?
BT 900 boom cylinder replacement
- Thread starter pbocco
- Start date
Same machine but not yet the problem.
Replaced all hoses year ago except those for the boom cylinder.
Asked dealer tech about boom cylinder and he said to get backend of machine 'up' on chocks or ramps so entire boom can lay out flat or even depressed as if digging hole stright down behind machine. Higher the machine can go--and lower the boom can be laid--the easier the job will be.
Do NOT rely on outriggers.
In home shop setting might need to have available a good heavy jack in case entire rear end of machine has to be lifted additionally.
Remove 'other' hoses as needed for access---all of them have to come off I think and be pulled out of 'S' at base of boom and laid aside. Have to pull that bottom pin to do this.
Drift pin out of 'top' holding cylinder.
NOTE think about this: might need to leave 'other' hoses hooked up until after removing top pin so cylinder can be retracted to shorten it's total length. Depends how much working room you have to lay boom down. If move valve wrong way and hose loose you can lose fluid and have 'other' hose whipping around.
Drift out bottom cylinder pin. NOTE may have done this to get hoses out of boom base 'S' but temporarily reinstalled to hydralically actuate cylinder in order to 'shorten' it for removal after drifting out top pin.
Slide cylinder out of boom removing hose(s) as you go. Caution heavy.
To reinstall KubotaTech says he uses a long skinny arm and a cut-off shovel handle to reach up inside boom and align top of cylinder head and hole in boom before installing pin.
NOTE think about this: might need to reinstall top hose first before pinning and then second hose and use hydraulics to gently extend cylinder until bottom pin holes line up. Watch those fingers and tools when moving cylinder rod slowly. Depends...
Be sure to replace boom cyl hoses at this point too. Also perhaps new pins depending on wear.
Regarding hoses, consider getting a set of hydraulc 'service' wrenches--not cheap but well worth it. Also I found a set of SAE flare-nut crow-foot wrenches (Craftsman best deal for the money) to be lifesavers. Otherwise some of my hoses would still be stuck. To go back together with enough wrench-room I had to install a 1-inch long male x female extension on two valve-body ports. I think you'll find the same thing swapping out boom cyl hoses.
If change out hoses at valve body note I found the valve body itself has adapters to which hoses attach. Some of these came loose others didn't. May have to use very skinny thin 'tappet' wrench to hold backup on valve body adapter to get hose off.
If you replace 'other' hoses that travel inside boom before exiting through slots for connection to external cylinder(s)---double check swivel-nut sizes on hose-ends against size of slots in boom or may not have passage to fit through. At big commercial hose shop got good hoses but out of all some had different nut sizes even though all fittings pulled from same bin in shop (I watched). Also if you go with 'modern' 4-wire hydraulic hoses instead of OEM 2-wire reinforcement note hose OD will be slightly larger. To prevent wear use hard plastic polyethylene spiral-wrap on hoses where they pass through the boom slots to external cylinders.
This is repeating what I've been told how to do the boom cyl R&R but not having done it myself and thinking it's upcoming.
NOTEs are intended to offer pause to think how your setup is and how you're approaching job especially how far 'down' you can lay your boom.
My hoe has never been off the machine and if using hydraulics to move things around I'd rather have the hoe on the machine--I think. IF enough hose slack and IF can remove hoe might be easier to set entire hoe off and on ground, laying boom out flat by letting platform console tilt waaayyy back.
If hoe is removed sitting on ground be CAUTIOUS breaking hose connections as something may move or collapse suddenly. Also true if mounted on tractor but perhaps slightly less likely to kill you.
I would personally appreciate your posting in-depth photos and description to assist mine upcoming.
Replaced all hoses year ago except those for the boom cylinder.
Asked dealer tech about boom cylinder and he said to get backend of machine 'up' on chocks or ramps so entire boom can lay out flat or even depressed as if digging hole stright down behind machine. Higher the machine can go--and lower the boom can be laid--the easier the job will be.
Do NOT rely on outriggers.
In home shop setting might need to have available a good heavy jack in case entire rear end of machine has to be lifted additionally.
Remove 'other' hoses as needed for access---all of them have to come off I think and be pulled out of 'S' at base of boom and laid aside. Have to pull that bottom pin to do this.
Drift pin out of 'top' holding cylinder.
NOTE think about this: might need to leave 'other' hoses hooked up until after removing top pin so cylinder can be retracted to shorten it's total length. Depends how much working room you have to lay boom down. If move valve wrong way and hose loose you can lose fluid and have 'other' hose whipping around.
Drift out bottom cylinder pin. NOTE may have done this to get hoses out of boom base 'S' but temporarily reinstalled to hydralically actuate cylinder in order to 'shorten' it for removal after drifting out top pin.
Slide cylinder out of boom removing hose(s) as you go. Caution heavy.
To reinstall KubotaTech says he uses a long skinny arm and a cut-off shovel handle to reach up inside boom and align top of cylinder head and hole in boom before installing pin.
NOTE think about this: might need to reinstall top hose first before pinning and then second hose and use hydraulics to gently extend cylinder until bottom pin holes line up. Watch those fingers and tools when moving cylinder rod slowly. Depends...
Be sure to replace boom cyl hoses at this point too. Also perhaps new pins depending on wear.
Regarding hoses, consider getting a set of hydraulc 'service' wrenches--not cheap but well worth it. Also I found a set of SAE flare-nut crow-foot wrenches (Craftsman best deal for the money) to be lifesavers. Otherwise some of my hoses would still be stuck. To go back together with enough wrench-room I had to install a 1-inch long male x female extension on two valve-body ports. I think you'll find the same thing swapping out boom cyl hoses.
If change out hoses at valve body note I found the valve body itself has adapters to which hoses attach. Some of these came loose others didn't. May have to use very skinny thin 'tappet' wrench to hold backup on valve body adapter to get hose off.
If you replace 'other' hoses that travel inside boom before exiting through slots for connection to external cylinder(s)---double check swivel-nut sizes on hose-ends against size of slots in boom or may not have passage to fit through. At big commercial hose shop got good hoses but out of all some had different nut sizes even though all fittings pulled from same bin in shop (I watched). Also if you go with 'modern' 4-wire hydraulic hoses instead of OEM 2-wire reinforcement note hose OD will be slightly larger. To prevent wear use hard plastic polyethylene spiral-wrap on hoses where they pass through the boom slots to external cylinders.
This is repeating what I've been told how to do the boom cyl R&R but not having done it myself and thinking it's upcoming.
NOTEs are intended to offer pause to think how your setup is and how you're approaching job especially how far 'down' you can lay your boom.
My hoe has never been off the machine and if using hydraulics to move things around I'd rather have the hoe on the machine--I think. IF enough hose slack and IF can remove hoe might be easier to set entire hoe off and on ground, laying boom out flat by letting platform console tilt waaayyy back.
If hoe is removed sitting on ground be CAUTIOUS breaking hose connections as something may move or collapse suddenly. Also true if mounted on tractor but perhaps slightly less likely to kill you.
I would personally appreciate your posting in-depth photos and description to assist mine upcoming.
pat331
New member
Equipment
L35, mower, bushhog, cement mixer, grader, boxblade, forks, posthole digger
bpocco, I've had the boom cylinder out of mine twice. It is no fun. The first time was to have the cylinder rebuilt and the second time was to install all new hoses. I mounted the backhoe on the tractor and moved the boom all the way to one side. I was then able to pull the pins and pull the cylinder out. It is heavy and offers many way to mash fingers and plenty of opportunies to invent new cuss words. I just wish I'd went ahead and replaced my hoses when I had it out the first time. Mine is a 1998 model and the hoses all started failing at about the same time. I bought most of my hoses from Surplus Center (https://www.surpluscenter.com). They are much cheaper than having them made locally. There was a couple I had to have made, but I don't remember which ones at the moment. Hope this helps and good luck!
I just removed the cylinder and replaced the 6 hoses. I followed the step you mentioned, rotate the hoe 90 degrees to the left from the operator chair. Then extend the dipper and boom out. I needed to get the boom centerline about 10 degrees below horizontal. In order to do that I needed to remove the pin between the dipper and boom. That allowed me to lower the boom another 12 to 14 inches and get the boom angled down. Once I did that I used the cylinder hydraulics to retract the cylinder and it just barely cleared the boom swing knuckle. You will need to use your hoses to run bypass each valve block not in use with your loose hoses. Once the cylinder is replaced with new hoses, it takes a bit of work to get new hoses up along side the boom cylinder for the dipper cylinder and bucket cylinder. Make sure you tag your hoses. I used brass washers stamped with a punch numbers one to six.
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To replace the boom cylinder on BT900. Once the hoes are installed slide the cylinder into the boom till you see the top edge of the cylinder pin hole. I made a wooden pin from a hanger rod and shaped a point on one end about the length of the pin. I was able to raise the boom cylinder from the other side with screwdriver and align the pin hole and slide the wooden hanger rod to position. Then as I drove the pin I could do minor adjustments with the hanger rod. The pin outside the boom could be aligned using the hydraulics and the hanger rod.
I normally just take the dipperstick off, allows the boom to drop low enough to make it easier to remove the cylinder without having to raise the back end of the tractor so high that it makes it hard to deal with. It takes about 5 minutes to take off the dipperstick. Bolt, pin, two hoses. Mark the hoses. Once you have the boom on the ground, remove the pin from the backhoe (front side), then use the hydraulic system to "suck" the ram in a little. shut the motor off, remove the rear pin, then you can manually pull the cylinder out far enough to get the hoses off, then remove the cylinder. Rebuild it on the bench then reinstall it in the reverse order. Looks dreadful but it's really not that bad. Just make sure to get the hoses back on the boom cylinder correctly and routed correctly. I like to mark a line across the hose and the cylinder fitting to get them lined up the same way they came off, and that makes it a LOT easier to get everything stuffed back into the boom without a kinked or mashed hose.
Took me two days of cussing and fiddling around with the hoe trying to get the farthest boom cylinder pin back in and lined up. Tried everything I could think of and got very frustrated. There just isnt any clearance to work because of all the hoses being in the way. I almost gave up but finally got it. Heres how I did it: Hoe not mounted to tractor but hydraulic line connected. Lay boom, dipper and bucket as flat as possible. Dig a small hole under the back of the platform so that the part of the boom that is closest to the operator chair can be angled lower than the rest of the boom using the hydraulics and with the tractor running. Do not connect the front boom pin yet. You must get the rear pin slid in first otherwise you will be fighting it all day (Trust me) Drill a small hole on the underside of the boom directly in line where the rear pin goes. I then used a long bolt thru the drilled hole to help push the cylinder up into place to get the pin aligned. Once the rear pin is in the rest is a piece of cake. Hope this will help someone else save some time.
My take on this task. Make sure you have clearance to drive boom pin out the lift boom with engine hoist, pull cylinder. Will try to update how hard it is to get back together
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So only had to put the cylinder in and out 3 times. first time put the cylinder in with the hose ports up like i took it out, but this really crowds the hoses so 2nd time in I put the hose ports down, much better. Wife helped me stick the pin inside the boom as i positioned it. Then positioned all the hoses in the rod eye slot let the boom cylinder down until pin holes lined up (this is very important take your time here to really get the holes lined up) Put the boom pin in and drive it through. be sure to line up the pin fixing holes before you drive it all the way in. I used a round wrecking bar to get the boom cylinder rod eye in to seat on top of the hoses underneath it. Again got the wife to stab the pin. painful bits - second time i drove the boom pivot pin out it was in a slight bind and used a lenght of 1 inch pipe to drive it out all the way. when you drive this pin out make sure you can wiggle the boom on the pin back and forth easily before driving out. I rate this job a 3x meaning it took me 3 times more than what I though it would. For reference 2x is about normal, meaning normal job take me about 2 times longer than i think it will and real bitch jobs are 20X.