Backhoe problem

[2515R Dude]

OK. So it's time to start eliminating things.
BTW, that feed and return to the hoe looks like a homebrew hydraulic extention rather than factory remotes.

It was installed by the dealer when i purchased the tractor+BH

By the way, are you sure you don't have those hoses reversed? Do the fittings make that impossible?

They are different, no way to reverse, only one way to connect, besides, it worked this way before.
I attached the pictures of them

An important piece of info is whatever is going on affects all the BH functions. That means it isn't an air bubble in a cylinder or a bad backhoe control valve.

So far for me it looks like it does affect all the functions, the turn and the curl of the boom are affected for sure.

Check the hoses for reversed first. Darn, I wish I was there with my pressure gauge.

Checked, they are not, and yes, i wish too. You would make a lot of money here because of the complete lack of tractor mechanics.

Nest gently tap on the pressure relief valve or feel of it to see if it is jumping. The relief valve is usually the longest cylinder jutting out from the control valve block. Sometimes there are several. A relief valve It is just a pressure spring and poppet valve. Sometimes you can hear it operate. In normal operation the pressure relief doesn't do anything. If that valve is cycling as the hesitation happens then that is the problem. It should be quiet.

BTW, does the engine load down when the hesitation happens or does it speed up? Any noises?
rScotty

The engine does not change it's RPMs, no audible changes that i can hear, and no noises coming from underneath the panel with the joysticks. I'll try to disassemble the cover panel and tap on them, but if it is a relief valve, shouldn't it be a constant thing, not jumping?

The dealer is suggesting to change the connectors. What do you think? In my limited knowledge and understanding, the connector ether works or not.

Thanks

 

[rScotty]

SNIP

The engine does not change it's RPMs, no audible changes that i can hear, and no noises coming from underneath the panel with the joysticks. I'll try to disassemble the cover panel and tap on them, but if it is a relive valve, shouldn't it be a constant thing, not jumping?

The dealer is suggesting to change the connectors. What do you think? in my limited knowledge, and understanding the connector ether works or not.

Thanks

Well, something should be changing with the engine. Maybe put a load on the backhoe and run the engine very slow.

Yes, a relief valve could be a constant thing....but they never are. The reason they aren not slow and constant is because fairly big orfice and open quickly to drop dangerous pressures fast.
So much so that it is common for them to dump the pressure, close, and have to reopen again a fraction of a second later. So they tend to make a high speed stuttering sound. Sometimes it happens so fast that what you hear sounds like a single shriek - it all depends on the orfice & spring size. Basically the same sound you hear when you crank the steering over to full lock on the family sedan.

But one thing is for sure, if you can put your hand on it you will feel the vibration as it oscillates. In five or ten seconds of relief that valve will get noticibly hotter too.

Yes, I like that dealer's suggestion. It certainly could be the connector internals. That's a good hint from him - and maybe he has seen it before. The thing that keeps the connector from leaking is just a ball valve with a spring and either of those can go bad. Mostly it is a corroded. Not often, but the cheaper quick connectors do have more problems than the expensive ones. And one with a loose ball or cracked spring could surely do just exactly what you are describing.

I'd swap them all. Cheaper than a mechanic call.

OH. I see in the photos that those connectors look to be standard aftermarket with standard thread. DO NOT use common plumbing fittings. It's just too dangerous. Please use hydraulic pressure rated parts. Any rural or tractor supply store should have them.
luck.
rScotty

 

[2515R Dude]

Well, something should be changing with the engine. Maybe put a load on the backhoe and run the engine very slow.

I put a load, noting changed as i could notice, no noise level, no RPM. The only difference was that it started running a little smother because of the increased inertia, it does not stop as abruptly as the empty one. Ran it 1K, 1.5 and 1.8RPM

So they tend to make a high speed stuttering sound. Sometimes it happens so fast that what you hear sounds like a single shriek - it all depends on the orfice & spring size. Basically the same sound you hear when you crank the steering over to full lock on the family sedan.

But one thing is for sure, if you can put your hand on it you will feel the vibration as it oscillates. In five or ten seconds of relief that valve will get noticibly hotter too.

I opened the panel and tried to listen, and put my hand on two things which i thought are the relief valves. #1 and #2 on the attached picture see below. No noise, no vibration. The only thing the #1 got a little warmer after my 5-10 swinging the boom.
The #2 had no changes.
BTW, which one is the relief, the #1 or #2?

Yes, I like that dealer's suggestion. It certainly could be the connector internals. That's a good hint from him - and maybe he has seen it before. The thing that keeps the connector from leaking is just a ball valve with a spring and either of those can go bad. Mostly it is a corroded. Not often, but the cheaper quick connectors do have more problems than the expensive ones. And one with a loose ball or cracked spring could surely do just exactly what you are describing.

He says he never had such an issue and this suggestion came from TYM.
Also, what supports the idea of the connectors, the problem started with 2 stops per swing every 1/3 of the way. After i disconnected and connected the BH it changed its behavior and now it makes 5-7 stops.
I checked the connectors inside, they look like new, no dirt, no rust no anything else.
Hopefully tomorrow i'll be able to get new connectors and install them

OH. I see in the photos that those connectors look to be standard aftermarket with standard thread. DO NOT use common plumbing fittings. It's just too dangerous. Please use hydraulic pressure rated parts. Any rural or tractor supply store should have them.
luck.
rScotty

Are you saying that that those ones are not good connectors? Which ones should i buy and how can i see the difference between the good ones and bad ones?

Also, i took a picture of the connection where the hose is connected. I guess it is PB point?

 

[oldnslo]

I am late to the party but does this happen with tractor at idle vs higher RPMs? Reason for asking is that sometimes the QD will be fine at lower flow but fail at higher flows.

 

[ptsg]

I put a load, noting changed as i could notice, no noise level, no RPM. The only difference was that it started running a little smother because of the increased inertia, it does not stop as abruptly as the empty one. Ran it 1K, 1.5 and 1.8RPM

I opened the panel and tried to listen, and put my hand on two things which i thought are the relief valves. #1 and #2 on the attached picture see below. No noise, no vibration. The only thing the #1 got a little warmer after my 5-10 swinging the boom.
The #2 had no changes.
BTW, which one is the relief, the #1 or #2?

He says he never had such an issue and this suggestion came from TYM.
Also, what supports the idea of the connectors, the problem started with 2 stops per swing every 1/3 of the way. After i disconnected and connected the BH it changed its behavior and now it makes 5-7 stops.
I checked the connectors inside, they look like new, no dirt, no rust no anything else.
Hopefully tomorrow i'll be able to get new connectors and install them


Are you saying that that those ones are not good connectors? Which ones should i buy and how can i see the difference between the good ones and bad ones?

Also, i took a picture of the connection where the hose is connected. I guess it is PB point?

On the first picture, the #1 is a check valve that prevents you from running the BH if you accidentally swapped the hoses and fed pressure via the Tank port on the BH control valve.

#2 is the main relief valve for the control valve of the BH.

On the second picture, the line where the arrow is pointing is indeed the PB line that will feed the BH.

 

[2515R Dude]

I am late to the party but does this happen with tractor at idle vs higher RPMs? Reason for asking is that sometimes the QD will be fine at lower flow but fail at higher flows.

Any rpm

 

[2515R Dude]

On the first picture, the #1 is a check valve that prevents you from running the BH if you accidentally swapped the hoses and fed pressure via the Tank port on the BH control valve.

#2 is the main relief valve for the control valve of the BH.

On the second picture, the line where the arrow is pointing is indeed the PB line that will feed the BH.

Interesting, meaning there is something wrong with the check valve because it got warmer. In my understanding, if it's función only to prevent backward connection, it should not work at all - get warmer ?

 

[ptsg]

Interesting, meaning there is something wrong with the check valve because it got warmer. In my understanding, if it's función only to prevent backward connection, it should not work at all - get warmer ?

It should get at least the same temperature as the hydraulic fluid gets, probably slightly higher since it may cause a slight restriction there.

Even if it was bad, it wouldn't really affect much on the BH unless the hoses were connected backwards, but you already said it's not even possible.

 

[2515R Dude]

OK, so my understanding was wrong. So, what is left? Connectors?

 

[K5lwq]

I support the connector plan. One thing that concerns me is that if I understand correctly you are only seeing the pause in one direction of movement and not the other. I understand on multiple functions but only one way. Is that correct? If so that leads me to suspect the valve itself as a problem.

That is a stack type valve so there could be an issue with where the spool valves mate together. Or if it is only on the two functions, swing and boom curl then maybe you could swap spool valves to test. But that would be a process and somewhat time consuming.

So you don’t see the symptoms when curling the bucket?