BH 77 Backhoe on a L2501 boom drifting down and no power to return back to lock position. 207 hours

[Gus1957]

Hello,

Need trouble shooting advice on boom drifting down.
Machine sat in the barn all winter and worked when put away.
All other hydraulic functions work and sight glass looks ok - reality is can't tell level with clear oil. No visible external hydraulic leaks.

1st time out digging only about 2' deep and felt loss of power retracting boom towards tractor. Had to rev up engine to get it to return. Seemed to work again and then noticed boom slowly dropping when out of hole.

Revved it again to get back to upright to put lock on and get it back to the barn.

Looking at Messicks parts diagrams looks like there could be a couple different model BH77's ? This is about 10 years old.

Looks like cylinders have threaded collars that can be taken apart and repaired if seals around piston are bad.

Appreciate ideas: TY

 

[Shawn T. W]

I don't have one of these, but I have a few questions ...

Does the front loader work normal?

Does the transmission work normal?

If both are working normal, I'd guess the fluid level is OK, but I'd want to be SURE!

I have a sight glass, it is a pain to see, especially with the backhoe on!

One thing I've done is raise the loader as high as it will go, and "dump the bucket" fully extracting the pistons, this will lower the level of fluid in the transmission ...

Look at the sight glass ... Lower the loader 6" look again ... At some point you should be able to see "the line" ...

It should look like this ... Picture "stolen " from another post somewhere on this site ... !



I ended up adding dye to mine, it now looks like this . . .

 

[Gus1957]

Shawn,

Yes loader and other Backhoe hydraulic controls work as normal. I'll play with loaded height tomorrow and look at level. My sight glass is silver which doesn't help with contrast trying to see level with old eyes.

Mine has a gear transmission.

TY

 

[TheOldHokie]

Hello,

Need trouble shooting advice on boom drifting down.
Machine sat in the barn all winter and worked when put away.
All other hydraulic functions work and sight glass looks ok - reality is can't tell level with clear oil. No visible external hydraulic leaks.

1st time out digging only about 2' deep and felt loss of power retracting boom towards tractor. Had to rev up engine to get it to return. Seemed to work again and then noticed boom slowly dropping when out of hole.

Revved it again to get back to upright to put lock on and get it back to the barn.

Looking at Messicks parts diagrams looks like there could be a couple different model BH77's ? This is about 10 years old.

Looks like cylinders have threaded collars that can be taken apart and repaired if seals around piston are bad.

Appreciate ideas: TY

View attachment 174123 View attachment 174124 View attachment 174125

The boom work section in the control valve has port reliefs on both ports. You might want to run a few carefully targeted pressure tests before tearing into the cylinder.

Dan

 

[Gus1957]

 

[TheOldHokie]

View attachment 174156

Now that you have a 12 minute utube video telling you what I said in two sentences (post #4) where do you go next?

Dan

 

[Gus1957]

Dan,

Can you explain how to test this relief valve ?
Have you seen this problem on a BH77 ?

I'm going to remove it and take a look at it to start.
Ask my Kubota dealer if they can test it.
I was thinking it would be a $100 part, but not even close: Messicks $582.08

TY

 

[TheOldHokie]

Dan,

Can you explain how to test this relief valve ?
Have you seen this problem on a BH77 ?

I'm going to remove it and take a look at it to start.
Ask my Kubota dealer if they can test it.
I was thinking it would be a $100 part, but not even close: Messicks $582.08

TY

Yes I have seen this problem here.

Your Kubota dealer is not going to test the valve once its off the tractor.

Before removing the vslve test it yourself. You will need a 3000 PSI test guage and a short hydraulic hose that you can buy for less than $50. If the valve does not test out then you can remove and inspect it. Unless there is some crap you can remove stuck in the orifices its replace only @$600.

Dan

 

[Shawn T. W]

Here's a gauge . . . https://www.boltonhooks.com/product/hydraulic-pressure-test-gauge/

 

[TheOldHokie]

Here's a gauge . . . https://www.boltonhooks.com/product/hydraulic-pressure-test-gauge/

He is going to need a direct connection to the control valve

https://a.co/d/09kHPoO9

https://a.co/d/02iZhCTq

2405-06-04 Hydraulic Fitting 3/8" Male JIC X 1/4" Female Pipe Carbon Steel: Amazon.com: Industrial & Scientific

2405-06-04 Hydraulic Fitting 3/8" Male JIC X 1/4" Female Pipe Carbon Steel: Amazon.com: Industrial & Scientific

a.co

 

[Gus1957]

05/12/2026 Kubota road tech was here to trouble shoot boom problem.
> FYI: I switched the pressure relief valves from the stabilizer to the boom to be able to continue working that day. And after 5 hours boom in control went totally dead. Had to lift boom with my other tractor to get boom into lock position for driving back to the barn. Both valves left in that position.

The tech first switched the hoses on the boom and found he could pull boom in / but no pressure out. Stated he was 99% sure spool inside this valve body was damaged and unit needed replacing.
He called dealer for a parts quote of $1,700 + 5 hours labor. Written quote needs to be emailed.
When I asked what happens if it's not this valve body - He thought he would put a pressure gauge test on it. Took out a large test kit and none of the fittings went on the valve block.
I asked what happens if its not the valve block and he said it could be leaking by the cylinder internally.

Then I asked how about taking another hose from a different block and trying to it to eliminate the cylinder.
So he took both hoses from stabilizer and attached to boom valve block. Stabilizer would come up ok, but when all the way down the stabilizer couldn't lift the tractor.

You could not hear any of the pressure relief valves blowing by as he stated.

Waiting for a written estimate.

 

[TheOldHokie]

05/12/2026 Kubota road tech was here to trouble shoot boom problem.
> FYI: I switched the pressure relief valves from the stabilizer to the boom to be able to continue working that day. And after 5 hours boom in control went totally dead. Had to lift boom with my other tractor to get boom into lock position for driving back to the barn. Both valves left in that position.

The tech first switched the hoses on the boom and found he could pull boom in / but no pressure out. Stated he was 99% sure spool inside this valve body was damaged and unit needed replacing.
He called dealer for a parts quote of $1,700 + 5 hours labor. Written quote needs to be emailed.
When I asked what happens if it's not this valve body - He thought he would put a pressure gauge test on it. Took out a large test kit and none of the fittings went on the valve block.
I asked what happens if its not the valve block and he said it could be leaking by the cylinder internally.

Then I asked how about taking another hose from a different block and trying to it to eliminate the cylinder.
So he took both hoses from stabilizer and attached to boom valve block. Stabilizer would come up ok, but when all the way down the stabilizer couldn't lift the tractor.

You could not hear any of the pressure relief valves blowing by as he stated.

Waiting for a written estimate.

If he did not even mention the relief valves he is clueless. Spool my a$$. I will bet dollars to donuts the relief on one work port is wide open which is why you have pressure on one direction and no pressure in the other direction. But hey - what do I know.

Dan

 

[Gus1957]

Dan,

Based on your comment here then it would be the upper relief valve that is open since when I swapped the lower ones the boom worked properly for 5 hours ? Does that make sense?

He said the parts person told him that when you get the valve body block it comes with bot relief valves in it along with I think he said 5/6 O-rings. This doesn't sound correct and will check the written estimate .

 

[TheOldHokie]

Dan,

Based on your comment here then it would be the upper relief valve that is open since when I swapped the lower ones the boom worked properly for 5 hours ? Does that make sense?

He said the parts person told him that when you get the valve body block it comes with bot relief valves in it along with I think he said 5/6 O-rings. This doesn't sound correct and will check the written estimate .

It would be the relief on the port that has no pressure. The reliefs are not interchangeable.

I would expect a new valve comes with all new orings and possibly both reliefs.

Dan

 

[TheOldHokie]

It would be the relief on the port that has no pressure. The reliefs are not interchangeable.

I would expect a new valve comes with all new orings and possibly both reliefs.

Dan

BTW - the reliefs are set higher than max tractor pressure so if theyvarecwirkinh you cant make them open with just tractor pressure.

Dan

 

[Gus1957]

1.Trying to better understand the relief valves. Internally they are only a based on strength of the spring. If there is no dirt or metal contamination - what could be wrong with it after 100 hours?

2. Tech said he could take valve bank apart here and with pressure relieved removing the 1st 2 valves the rest should stay in place. Does that make sense with all the O-rings in between each valve block?

 

[TheOldHokie]

1.Trying to better understand the relief valves. Internally they are only a based on strength of the spring. If there is no dirt or metal contamination - what could be wrong with it after 100 hours?

2. Tech said he could take valve bank apart here and with pressure relieved removing the 1st 2 valves the rest should stay in place. Does that make sense with all the O-rings in between each valve block?

Dirt or a broken spring in the relief. It really dies not matter if its not working its not working. Yes to the valve disassembly.

Dan