Some of you may remember my Post about my B2601 breaking in half!

South 40

Active member

Equipment
L1500DT, 750 Ford backhoe, 49 D4 Cat Repowered with 6.9L Diesel
Nov 12, 2012
157
45
28
Bloomsdale, Mo. USA
After I exit my driveway, there is a slight incline, I stopped and began filming before I went up the incline.

First video

The second video is after I crested the incline.

https://youtube.comhttps://youtube....eature=share/shorts/L7cuSXqv7JY?feature=share
Hey Folks,

That is NOT a hyd sound, that is something mechanical grinding and binding and the hyd can't overcome it.

In the first vid you can hear the sound raise and lower as it goes, sounds like something mechanical is out of round, I'm betting you still have damage from the accident that hasn't been found/addressed/fixed yet.

Cheers
Samantha
 

torch

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Equipment
B7100HSD, B2789, B2550, B4672, RC54-71B, 48" cultivator, homemade FEL and Cab
Jun 10, 2016
2,198
435
83
Muskoka, Ont.
Sounds to me like the HST is sucking air. You are absolutely sure of the fluid level? No way it could be borderline low, dropping below the suction with the FEL raised and hills/acceleration sloshing the fluid to one end of the case? I had this happen when a bolt came loose and my case was slowly dripping fluid, unnoticed until I tried to go up a hill and it started making similar noise. Could only proceed with gentle pedal pressure. Got it back to the garage, topped off the fluid, tightened the leaking bolt and has been fine since.
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
3,654
1,387
113
North of Pittsburgh PA
Hey Folks,

That is NOT a hyd sound, that is something mechanical grinding and binding and the hyd can't overcome it.

In the first vid you can hear the sound raise and lower as it goes, sounds like something mechanical is out of round, I'm betting you still have damage from the accident that hasn't been found/addressed/fixed yet.

Cheers
Samantha
Second video does not work for me, but after viewing the first one I feel the same as Samantha.

What I did not pick up, was if the tractor slowed during the times when the sound increased in volume. This is what I would expect to happen if something was stripped and catching/not catching.

Not sure why this would be an intermittent thing though...
 

ACDII

Well-known member

Equipment
B2410, L352 Loader, Woods BH70-X backhoe
Oct 21, 2021
574
343
63
Illinois
More than likely an internal crack in the case is the root cause. Somehow, somewhere there is a fluid leak that is preventing the pump from providing power to the gear set. If nothing is binding in the case, then its in the pump.

Just a thought, but have you had the pressure reliefs tested to make sure they aren't busted or weak?
 

South 40

Active member

Equipment
L1500DT, 750 Ford backhoe, 49 D4 Cat Repowered with 6.9L Diesel
Nov 12, 2012
157
45
28
Bloomsdale, Mo. USA
Hey Folks,

The sound I hear in the first video, (like Henro the second video doesn't work for me), is not the sound hydraulics make if there is a problem, all I hear is something mechanical having an issue.

If there is something in the final drive, axle, whatever it is when power is applied it grinds, and then when power is lost it relaxes and starts "trying" to work again, basically once the tension is off of it then it can relax and return the the "ideal working position" until power is applied again, then it goes until it completely binds up and the hydraulics can no longer overcome the tension.

I am thinking in the accident when it hit the ground something inside the axle/axles got broken and that is where the problem is now, it could be something as simply as a clip that got shoved out of it's grove, maybe another bad bearing, or it could be where a hydraulic pump/motor/shaft connects, regardless that sound is not from the hydraulics.

The OP has already said if he tries it while jacked up it works fine, which means it's the rolling resistance that is causing the problem.

My best advice is to just take it to a service center and get someone that really knows that tractor to go thru it, I think you will surprised what they find.

I can't do it until I get my 1500 running again but I will post when a hydraulic issue sounds like.

Cheers
Samantha
 

Egressman

Member

Equipment
B2601
Sep 7, 2016
140
7
18
Richmond, IN, United States
Hey Folks,

That is NOT a hyd sound, that is something mechanical grinding and binding and the hyd can't overcome it.

In the first vid you can hear the sound raise and lower as it goes, sounds like something mechanical is out of round, I'm betting you still have damage from the accident that hasn't been found/addressed/fixed yet.

Cheers
Samantha
Negative, I had this tractor torn down to nuts and bolts. Mechanical problems don’t just cause the power to go away,
 

Egressman

Member

Equipment
B2601
Sep 7, 2016
140
7
18
Richmond, IN, United States
Sounds to me like the HST is sucking air. You are absolutely sure of the fluid level? No way it could be borderline low, dropping below the suction with the FEL raised and hills/acceleration sloshing the fluid to one end of the case? I had this happen when a bolt came loose and my case was slowly dripping fluid, unnoticed until I tried to go up a hill and it started making similar noise. Could only proceed with gentle pedal pressure. Got it back to the garage, topped off the fluid, tightened the leaking bolt and has been fine since.
I put almost 4 gallons of fluid in it lol! It’s not leaking fluid, so where would it go? It drops power under load. Not incline. It’s the load because of the hill!

It only calls for 12qts.

Before I fixed the suction problem!
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
3,654
1,387
113
North of Pittsburgh PA
Just a thought, but have you had the pressure reliefs tested to make sure they aren't busted or weak?
I think this is a great thought. When I dead end a cylinder I can hear the PRV activate, but the sound is not like what is shown in that video.

BUT if a PRV WAS defective, maybe it might make a sound like that. Increased load likely means increased system pressure...PRV trips, pressure drops, power drops...sound continues...

Sound stops because the PRV closes, system pressure increases, power increases...
 

Egressman

Member

Equipment
B2601
Sep 7, 2016
140
7
18
Richmond, IN, United States
Thanks for you thoughts, The accident was in 2018 I believe and the tractor has functioned as required has function as required until about two months ago until about two months ago.

Not to say that something just now broke but I had a three point hitch problem that required me to change the hydraulic control valve. In order to do so I had to disassemble the tractor.

When I disassemble the tractor that’s when I found the steel ring in the PTO case. That force me to takeoff the two rear axles and the PTO case.

Once I separated the PTO case the axles I still wasn’t able to find what was broke. So I removed the second casting that holds all the transmission parts. It was there that I found the bearing that had broke. I ordered and replace the bearing cleaned everything out and reassemble the tractor.

It was then that I service the hydraulics and filled the system and ran the tractor while all four tires were off the ground. You can see the video where it’s pushing aerated fluid. The great mines on here told me I had a suction problem and I located the suction problem and replaced all the parts.

With the The tractor in the air I had steering, loader, forward, reverse, and four-wheel-drive and all three ranges.

It was then that I completely assembled the rear end and fix the three point hitch, after the top half of the PTO section was put on and all the lines were put together I was able to run the PTO up and down and test it.

It was that point when I assemble the seat all the control levers the fenders the floor and basically put the tractor back to 100% almost.

The problem that developed the few weeks before was still there and I had no power underload. My three point hitch worked perfectly though.

I’m gonna post the link to the video of the hydraulics running and my function test, this is while it still had a suction leak.

Kubota B2601 suction issue
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
3,654
1,387
113
North of Pittsburgh PA
Thanks for you thoughts, The accident was in 2018 I believe and the tractor has functioned as required has function as required until about two months ago until about two months ago.

Not to say that something just now broke but I had a three point hitch problem that required me to change the hydraulic control valve. In order to do so I had to disassemble the tractor.

When I disassemble the tractor that’s when I found the steel ring in the PTO case. That force me to takeoff the two rear axles and the PTO case.

Once I separated the PTO case the axles I still wasn’t able to find what was broke. So I removed the second casting that holds all the transmission parts. It was there that I found the bearing that had broke. I ordered and replace the bearing cleaned everything out and reassemble the tractor.

It was then that I service the hydraulics and filled the system and ran the tractor while all four tires were off the ground. You can see the video where it’s pushing aerated fluid. The great mines on here told me I had a suction problem and I located the suction problem and replaced all the parts.

With the The tractor in the air I had steering, loader, forward, reverse, and four-wheel-drive and all three ranges.

It was then that I completely assembled the rear end and fix the three point hitch, after the top half of the PTO section was put on and all the lines were put together I was able to run the PTO up and down and test it.

It was that point when I assemble the seat all the control levers the fenders the floor and basically put the tractor back to 100% almost.

The problem that developed the few weeks before was still there and I had no power underload. My three point hitch worked perfectly though.

I’m gonna post the link to the video of the hydraulics running and my function test, this is while it still had a suction leak.

Kubota B2601 suction issue
So it seems that:

Your tractor seems to have an issue with the HST pump circuit, and not the hydraulic circuit that probably has a separate pump, and is independent of the HST circuit.

Your problem is that the tractor loses power to move when it is under load. The hydraulic circuit that includes the loader and 3PH seem to work normally, but you don't mention if you tested them when the issue was occurring. Loader would be easy to operate at that point in time.

There is a screeching sound when the problem happens. BUT with little or no load, there is no screeching sound, and the tractor seems to move normally.

Question is: What is causing the screeching sound and loss of motive power?

Is there a PRV somewhere in the HST circuit? I don't have a clue. but would probably check if I were having this problem.

If not, is there something that could cause the HST pump itself to start making that noise, and to lose pressure?

Is there ANY chance a splined shaft or something similar could be stripped but still offering enough resistance to turn the mechanical system normally when only lightly loaded?

Can someone else add some possibilities to the list?

Bottom line is the OP has a problem. This is real. At this point the cause is also real but unknown.

Perhaps we can list possibilities, and reasons why they might cause the issue the OP is experiencing: Screeching sound and loss of motive power under load.

All for the purpose of helping the OP solve his problem, by perhaps suggesting something he has not thought about.
 

Egressman

Member

Equipment
B2601
Sep 7, 2016
140
7
18
Richmond, IN, United States
I'm looking at your picture, trying to figure out how this happened. I see two possibilities. First, it could have happened in the original accident. Second, it could have happened during reassembly after replacing the filter housing. The angle of the pipe and the return bend of the flange argue towards a failure of the pipe to fully seat, possibly due to the grey goo (gasket maker?) surrounding the pipe. I wonder if the apparent sealant prevented full engagement, and then torquing the bolt bent the flange.

Of course, it is equally possible that the flange was bent to that angle by the damage to the original housing. When installed in the new housing, the bent flange prevented the pipe from fully seating. Did you realize this was happening? Is that why sealant was applied?

Regardless of the cause, I am concerned about two possible cracks in the flange, circled in red, below:

View attachment 78063

I'm not certain they are cracks -- they could be some photographic artifact or perhaps some strings of sealant, but they do appear to be aligned with the bends. If they are cracks, they could be a point of future failure. I'm sure you are tired of giving Messicks money, but I think you should seriously consider replacing that pipe.

Personally, I'm not a fan of adding gasket makers or other sealants to o-ring sealed joints. I think it best to clean them well and apply a compatible lubricant to the O-ring (eg: a thin smear of the liquid to be sealed or perhaps some Parker Super-O Lube. Or even Vasoline). But: your tractor, your choice.
I failed to address this, what might be cracks are only on the bracket and they don't affect where it seals to the tractor.

Regardless, I have replaced “ALL” components on the suction side from the pump back to the sump.

That tube is no longer relevant to the problem. I did have a leak from the tube initially, that was initially corrected by sealing wit RTV.
 

ruger1980

Active member

Equipment
L4310 w/La682, L225
Oct 25, 2020
237
86
28
CNY
First question is the steering function well at all times? Then are you using the PTO and does it make a difference if the PTO is turned off?

You really need to have gauges in the HST A & B circuits to check charge and working pressure. While in forward you can read the forward working pressure on the forward circuit and the charge pressure on the other circuit. The difficulty is having gauges that can measure charge pressure and working pressure accurately. The best way is probably with transducers and digital gauges. That or install a 6000psi gauge in the forward circuit and a 2-300psi gauge in the other circuit. The problem with that is if you reverse the machine it will most likely destroy the low pressure gauge.
 

Egressman

Member

Equipment
B2601
Sep 7, 2016
140
7
18
Richmond, IN, United States
First question is the steering function well at all times? Then are you using the PTO and does it make a difference if the PTO is turned off?

You really need to have gauges in the HST A & B circuits to check charge and working pressure. While in forward you can read the forward working pressure on the forward circuit and the charge pressure on the other circuit. The difficulty is having gauges that can measure charge pressure and working pressure accurately. The best way is probably with transducers and digital gauges. That or install a 6000psi gauge in the forward circuit and a 2-300psi gauge in the other circuit. The problem with that is if you reverse the machine it will most likely destroy the low pressure gauge.
currently all I have is a 0 to 5000 PSI gauge with a 3/8 coupler on it. I could add a hose of any size And adapt it to male or female.
 

ruger1980

Active member

Equipment
L4310 w/La682, L225
Oct 25, 2020
237
86
28
CNY
currently all I have is a 0 to 5000 PSI gauge with a 3/8 coupler on it. I could add a hose of any size And adapt it to male or female.
That would work to measure high pressure but not charge pressure and that is the most important pressure to check. Also you need to check charge pressure while moving and the problem occurring to make a proper diagnosis.
 

ACDII

Well-known member

Equipment
B2410, L352 Loader, Woods BH70-X backhoe
Oct 21, 2021
574
343
63
Illinois
The PTO is directly driven from the crank of the tractor via a clutch, it is not hydraulically driven. I think PTO and 3 point hitch is being swapped about here by mistake. The 3 point hitch (3PH) is driven by the auxillary pump which is driven off the engine itself and is a totally separate system from the HST pump, they only share the reservoir of fluid. The Aux pump is a two pump system, one for the loader, Power Beyond, and finally 3PH. The second part is for the power steering, it is it's own system, similar to a car.

The transmission is driven by a pump that is encased between the engine and the gear box, the PTO is coupled through it, but not driven by it.

What I heard was a bleeding bypass valve. There are pressure relief valves in the HST that protect the system from a jammed gear train, but it takes a LOT to have them blow off pressure, I have stalled my tractor quite a few times putting it under heavy load and not had the valve bypass. I suspect you have a bad PRV that is releasing pressure way too low.

Here is what leads me to believe that besides the noise. You go no where in high gear. High gear requires the most pump pressure, while you are moving in low gear to a point, when the load builds up, it goes to bypass.

Second, a PRV releasing pressure can cause the fluid to foam. i believe earlier in this thread some diagrams were posted, take a close look at them and you can see where the PRV are in the circuit.

If you lock the brakes, and try to drive the tractor in either direction , ful throttle, full treadle and the tractor does NOT stall out, its a very high probability the PRV is bad.
 
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Egressman

Member

Equipment
B2601
Sep 7, 2016
140
7
18
Richmond, IN, United States
The PTO is directly driven from the crank of the tractor via a clutch, it is not hydraulically driven. I think PTO and 3 point hitch is being swapped about here by mistake. The 3 point hitch (3PH) is driven by the auxillary pump which is driven off the engine itself and is a totally separate system from the HST pump, they only share the reservoir of fluid. The Aux pump is a two pump system, one for the loader, Power Beyond, and finally 3PH. The second part is for the power steering, it is it's own system, similar to a car.

The transmission is driven by a pump that is encased between the engine and the gear box, the PTO is coupled through it, but not driven by it.

What I heard was a bleeding bypass valve. There are pressure relief valves in the HST that protect the system from a jammed gear train, but it takes a LOT to have them blow off pressure, I have stalled my tractor quite a few times putting it under heavy load and not had the valve bypass. I suspect you have a bad PRV that is releasing pressure way too low.

Here is what leads me to believe that besides the noise. You go no where in high gear. High gear requires the most pump pressure, while you are moving in low gear to a point, when the load builds up, it goes to bypass.

Second, a PRV releasing pressure can cause the fluid to foam. i believe earlier in this thread some diagrams were posted, take a close look at them and you can see where the PRV are in the circuit.

If you lock the brakes, and try to drive the tractor in either direction , ful throttle, full treadle and the tractor does NOT stall out, its a very high probability the PRV is bad.
You have described my problem exactly!
When the pressure is two great the valve pops and my pedal goes soft. In my case though the valve is doing this prematurely.
 

ACDII

Well-known member

Equipment
B2410, L352 Loader, Woods BH70-X backhoe
Oct 21, 2021
574
343
63
Illinois
You have described my problem exactly!
When the pressure is two great the valve pops and my pedal goes soft. In my case though the valve is doing this prematurely.
Yes, I believe that either it was misadjusted, if they can even be adjusted, or bad. Could have a weak or broken relief spring. 060 and 120 are the relief valve components.

2601hst.png
 

ruger1980

Active member

Equipment
L4310 w/La682, L225
Oct 25, 2020
237
86
28
CNY
The PTO is directly driven from the crank of the tractor via a clutch, it is not hydraulically driven. I think PTO and 3 point hitch is being swapped about here by mistake. The 3 point hitch (3PH) is driven by the auxillary pump which is driven off the engine itself and is a totally separate system from the HST pump, they only share the reservoir of fluid. The Aux pump is a two pump system, one for the loader, Power Beyond, and finally 3PH. The second part is for the power steering, it is it's own system, similar to a car.

The transmission is driven by a pump that is encased between the engine and the gear box, the PTO is coupled through it, but not driven by it.

What I heard was a bleeding bypass valve. There are pressure relief valves in the HST that protect the system from a jammed gear train, but it takes a LOT to have them blow off pressure, I have stalled my tractor quite a few times putting it under heavy load and not had the valve bypass. I suspect you have a bad PRV that is releasing pressure way too low.

Here is what leads me to believe that besides the noise. You go no where in high gear. High gear requires the most pump pressure, while you are moving in low gear to a point, when the load builds up, it goes to bypass.

Second, a PRV releasing pressure can cause the fluid to foam. i believe earlier in this thread some diagrams were posted, take a close look at them and you can see where the PRV are in the circuit.

If you lock the brakes, and try to drive the tractor in either direction , ful throttle, full treadle and the tractor does NOT stall out, its a very high probability the PRV is bad.
The PTO on the B2601 is engaged via a hydraulic clutch inside the transmission housing. The PTO valve is supplied by the same pump that supplies charge pressure to the HST so any issue there can prevent charge oil from reaching the HST. Without charge oil the HST will not drive the tractor and will make the sound he is experiencing.
If it were a PRV it should be consistent and generally in one direction or the other as they rarely ever fail in pairs. This can be checked by swapping relief valves. Either way the best way to diagnose is to install gauges in the forward and reverse loops to check working and charge pressure.