BH75 swing cylinder removal

[rwwhite47]

Have a swing cylinder failure and need to remove he cylinder to rebuild. Does anyone know if the Control Valve assembly on the BH75 need to be removed in order to get the swing cylinders out for repair? The workshop manual is vague. Just says to remove the support bar and then remove the swing cylinder.

Thanks

 

[PoTreeBoy]

Have a swing cylinder failure and need to remove he cylinder to rebuild. Does anyone know if the Control Valve assembly on the BH75 need to be removed in order to get the swing cylinders out for repair? The workshop manual is vague. Just says to remove the support bar and then remove the swing cylinder.

Thanks

You don't need to remove the valve.

Before you start, curl the bucket and set it on the ground so you can depressurize and take the load off everything. Or, make sure the travel pins are installed.

Mark and remove the hoses. Remove the pin retainers and knock the pins out of the swing frame. Remove the cylinder support bar bolts and bar. Then the cylinders should lift out of the trunnions in the main frame.

 

[Tarmy]

I have the BH 76…very similar. Those two rams work together. When one is in suction the other is in pressure…so a leak in one can be a pain to sort out,

 

[rwwhite47]

Thanks for the replies and advise. The reason I posed the question is because of the components that are part of the valve body appear to be in the way for the removal of the support bar. Guess I won't know for sure until I dig into it. Not a stranger to twisting a wrench. Just like to have some idea as to what I'm getting into before I start taking things apart.

Wasn't a problem locating the leak. The outer wiper seal herniated, most likely because an inner seal failure and the cylinder was spewing a steady stream when under pressure. I was able to set the travel pins before storing the tractor.

 

[rwwhite47]

Went out to do battle with the BH74 backhoe swing cylinder this afternoon. It became quickly obvious that the valve assy. has to be removed before you can get the support bar out. There are three parts of the valve assy. that extend down in front of the support bar and will not allow the support bar to be raised and removed (See attached images). To get the valve assy. out, I need to remove all of the hydraulic hoses and then start disassembling everything from the top down. When I get to the point that I can remove the valve assy., then I can lift the support bar out and remove the swing cylinder. Don't you just love compact things??

 

[PoTreeBoy]

Went out to do battle with the BH74 backhoe swing cylinder this afternoon. It became quickly obvious that the valve assy. has to be removed before you can get the support bar out. There are three parts of the valve assy. that extend down in front of the support bar and will not allow the support bar to be raised and removed (See attached images). To get the valve assy. out, I need to remove all of the hydraulic hoses and then start disassembling everything from the top down. When I get to the point that I can remove the valve assy., then I can lift the support bar out and remove the swing cylinder. Don't you just love compact things??

Oops, sorry for the bad advise .

Yeah, the components don't scale down as fast as the overall machine.

 

[rwwhite47]

Well, a gremlin has taken up residence in my backhoe assy. After having the swing cylinder repacked and replaced, the right stabilizer cylinder decided to leak. R&R on that one was fairly easy after the swing cylinder debacle. Then the digger cylinder decided to leak. Again a fairly simple R&R exercise.

After everything was done, I tested the system. Boom worked, arm worked, digger worked (although a little slower when dumping), boom swung right with no problem but when swinging left, it would only go about 30 degrees from neutral. If I power down the tractor, I can manually force the boom all the way over to the left. Then, with the tractor running, I could bring the boom to neutral, but it would still not go full left under hydraulic power.

I'm thinking that a seal in the cylinder is rolling and preventing the piston from going to full stop? Not looking forward to removing the cylinder and all that entails. May consider repairing it in place, if I can get a sizeable wrench in there to get the end cap off. Otherwise it's a full disassembly of all of the hoses and control valve assy. again.

Any thoughts?

 

[rwwhite47]

I was able the extract the swing arm cylinder rod from the cylinder without removing the cylinder from the tractor. One of the inner seals had disintegrated, everything still looked good. After replacing all of the seals and verifying that there were no scratches in the bore, I reinstalled the rod and the few hydraulic lines that needed to be disconnected. Long story short, the boom would still not swing all the way the the right.

I disconnected the rod arm from the boom and exercised the boom and discovered that the newly repacked cylinder wasn't working at all. Either my repack wasn't good or there is something wrong in the swing cylinder spool. When the rod was disconnected from the boom, it slowly extended and would not retract. I had to loosen the hydraulic connections to get it to retract. After I reconnected the rod to the boom, I could swing the boom using the left cylinder. Other than that, no change.

I have confidense in my work, so I think that I'll concentrate on the spool. Any thoughts or comments?