BX22 BT600 boom cylinder

[Forgie]

After 22 years of operation I had to reseal the boom cylinder on my BT600 backhoe. When reinstalled I lowered the boom and crushed the lower “L” fitting / metal tube into the inside of the boom tunnel. The fitting in the cylinder had not been removed or repositioned. There is no evidence of any bend in the cylinder rod. I replaced the fitting and metal tube and checked again. The boom can only be lowered about 1/2 way before it contacts the inside of the boom tunnel. The fitting into the cylinder is tapered and therefore can not be seated any deeper. I tried repositioning the fitting, but no position give any better clearance. There must be a simple solution, but it’s evading me.

 

[Henro]

After 22 years of operation I had to reseal the boom cylinder on my BT600 backhoe. When reinstalled I lowered the boom and crushed the lower “L” fitting / metal tube into the inside of the boom tunnel. The fitting in the cylinder had not been removed or repositioned. There is no evidence of any bend in the cylinder rod. I replaced the fitting and metal tube and checked again. The boom can only be lowered about 1/2 way before it contacts the inside of the boom tunnel. The fitting into the cylinder is tapered and therefore can not be seated any deeper. I tried repositioning the fitting, but no position give any better clearance. There must be a simple solution, but it’s evading me.

Just a wild guess, but is there any chance you reverse the orientation of the cylinder when you reinstalled it?

 

[loggin]

After 22 years of operation I had to reseal the boom cylinder on my BT600 backhoe. When reinstalled I lowered the boom and crushed the lower “L” fitting / metal tube into the inside of the boom tunnel. The fitting in the cylinder had not been removed or repositioned. There is no evidence of any bend in the cylinder rod. I replaced the fitting and metal tube and checked again. The boom can only be lowered about 1/2 way before it contacts the inside of the boom tunnel. The fitting into the cylinder is tapered and therefore can not be seated any deeper. I tried repositioning the fitting, but no position give any better clearance. There must be a simple solution, but it’s evading me.

Some pictures would definitely help us to see the issue and find some solutions.

 

[loggin]

Judging from pictures on the internet it looks like the rod end attaches to the frame of the backhoe and the cylinder end is inside the tube.

 

[PoTreeBoy]

Just a wild guess, but is there any chance you reverse the orientation of the cylinder when you reinstalled it?

Yeah, I had a similar situation on my BT900. It has to be rotated correctly.

 

[North Idaho Wolfman]

It should be oriented in this fashion:

 

[Forgie]

Cylinder is oriented as per drawing and the way it always was. To rule out a possible slight bend in the rod I rotated it 180* in the cylinder. Same condition, contacts top of boom tunnel when lowered less than 1/2 way.

 

[whitetiger]

Did you have the 90-degree fitting out of the cylinder? It does not appear to be screwed in far enough.

 

[North Idaho Wolfman]

Cylinder is oriented as per drawing and the way it always was. To rule out a possible slight bend in the rod I rotated it 180* in the cylinder. Same condition, contacts top of boom tunnel when lowered less than 1/2 way.

Have you replaced the fitting with a different fitting?
As @whitetiger pointed out it does not appear to be installed deep enough.
If it's a replacement fitting it could be the fitting is just taller.
You could tap the cylinder fitting to make the fitting seat deeper or use a die on the fitting do do the same thing.

 

[Forgie]

Originally I did not remove or reposition the fitting. After reinstalling the cylinder the first time I lowered the boom it crushed the metal pipe and cracked the fitting. I ordered the replacements from Kubota and they matched the original exactly. The fitting has tapered threads and is down as deep as I could get it. Counting threads it seems to be at the depth of the original. I’m going to stop by the local hydraulic shop and see if they may have one with a shorter profile. If not I guess I’m modifying the boom tunnel.

 

[Henro]

Originally I did not remove or reposition the fitting. After reinstalling the cylinder the first time I lowered the boom it crushed the metal pipe and cracked the fitting. I ordered the replacements from Kubota and they matched the original exactly. The fitting has tapered threads and is down as deep as I could get it. Counting threads it seems to be at the depth of the original. I’m going to stop by the local hydraulic shop and see if they may have one with a shorter profile. If not I guess I’m modifying the boom tunnel.

Was that fitting always on the top as shown in the photo? Is there any possibility the cylinder needs to be rotated 180° with respect to the shaft?

 

[Forgie]

Yes, the fitting was always on the top and that matches the drawings. Rotating the barrel 180* would put the fittings under. I have rotated the rod 180* and get the same results.

 

[TheOldHokie]

Yes, the fitting was always on the top and that matches the drawings. Rotating the barrel 180* would put the fittings under. I have rotated the rod 180* and get the same results.

How did you manage to crush the original? Apparently it was OK before you took it out and put it back. Seems like this is an assembly error. Like maybe its just not screwed in far enough.....

Dan

 

[Dustyx2]

Yes, the fitting was always on the top and that matches the drawings. Rotating the barrel 180* would put the fittings under. I have rotated the rod 180* and get the same results.

I just went out and looked at mine. The hoses are underneath. Opposite of what the drawing above shows. The cylinder has never been off.

 

[DustyRusty]

Kaching, Kaching, we have a winner. I was thinking the same thing, but since I sold my BX22, and my memory it old, I didn't want to make this suggestion.

 

[Dustyx2]

Kaching, Kaching, we have a winner. I was thinking the same thing, but since I sold my BX22, and my memory it old, I didn't want to make this suggestion.

I too was thinking that was wrong but I wanted to be sure before I said it.

 

[Forgie]

I was sure the fittings were on the top, and all of the Kubota drawings confirmed that. Well, we were both wrong, they definitely have to be on the bottom. Thank you Dustyx2 for taking the time to check out a factory original installation and posting pictures. Thanks to everyone for being so helpful.