BL4690A Backhoe Boom Cylinder/Hydraulic Hose Change

[Henro]

Hi,

I have been using my backhoe a lot this summer. Digging and moving between 3 & 400 cubic yards of earth.

Over the years I have had several hose failures. This summer I had one for the dipper cylinder fail. No big deal, but it caused me to dread the possibility of having to replace a hose to the boom cylinder, which is inside the boom.

Well, as luck would have it, I blew a hole in one of the boom cylinder hoses. I can not complain as the backhoe is over 15 years old. An internet search turned up one post somewhere that gave me an important hint: turn the boom to the side before removing the boom cylinder. Absolutely necessary.

I thought I would post post a couple things I learned when changing the boom cylinder hoses. I decided to do both hoses, even though only one failed. This is not meant to be a how to, but rather to share a couple pointers that may help someone in the future.

So the first thing is to turn the boom to the side so you can get the cylinder out.

Remove the clamps that hold the protective sheath on the hose at the cylinder end, as they protrude and get stuck when trying to pull the hoses out. Or better yet, just cut the ends of the hoses off with a hacksaw.

Pay attention to the orientation of the cylinder. It can go back in two ways. The wrong way is difficult to accomplish but not impossible. Do not ask me how I know this.

The boom needs to hang down a bit to get the cylinder out. I ended up using a couple 12 concrete blocks under the outriggers to raise the tractor enough to get the cylinder out. You could also just pick a spot with a slope to one side.

A broom stick tapered a bit can be used to push the other hoses apart when threading the new hoses back into place. Requires very little effort. Makes a nearly impossible task easy.

Cylinder will not come out if boom does not drop enough.



Cylinder will come out without too much difficulty. Use jackstands if you use concrete blocks to gain elevation. Blocks can fail...



Tapered broomstick made threading the hoses back in a simple task. Also proved handy positioning the cylinder end to accept the pin.



Hope this post helps helps someone in the future. The second time around, it only took me about an hour to remove, rotate, and reinstall the boom cylinder. It is really not that bad of a job once you do it. Pay attention to things as you remove them and you will only need to do it once. (Insert red face here).

Bill

 

[diesel85]

I do this similar tactic with man lifts. Like them Genie's.

 

[Michael_A]

Hello,

I just recently had to replace the lines in the boom of my Kubota 4690 Backhoe. I searched the internet for guidance and there wasn't much available. Henro's post above was the most help and many of his suggestions helped me DIY this fix. Here are a few takeaways for anyone else who may need to do the same project.

• Jacking up the backhoe higher then the stabilizers could get it was a must. I use a standard floor jack and a log to elevate it and then I put 6X6 scraps under to support it while working.
• 
• I only had a hole in one line but first intended to replace both lines to the Boom Cylinder. Once I removed the boom cylinder, I decided to replace all 4 that were in the Boom as they were all 20+ years old. To remove the two bucket lines in the boom you had to do as Henro suggested above. The two through boom fittengs needed to be loosened and removed at the same time. Tip one up and the second one down.
• 
• In order to get better access to thes fittings (not sure if it was 100% necesary) I disconnected the dipper from the boom.
• 
• When I had my lines rebuilt I had them made an inch or two longer so I had some play. I think this made the job a bit easier and any excess I could lose under the BH control panel.
• To reinstall the lines I used string and parts grabber:
• 
• Very doable but not much guidance available on the internet (especially 4690 specific)

I hope this is helpful to anyone who has to swap out thier 4690 Boom Hoses.