Kubota BX25D - Backhoe return line/quick connect getting hot

[analog]

Today I needed to swap out the backhoe for a tiller and when I was done and needed to reconnect the backhoe, I noticed the quick connect that goes back to the tractor from itself was hot to the touch, so much so that I had to very quickly undo it so I could get the backhoe line back on. Once it was on, and running for a few minutes, the return line from the backhoe got hot too. I smelled it and didn't smell any burned oil smell but it's definitely hot and not something I ever remember when doing this in the past. It was not hot when I went to take the backhoe off initially (even though I had been running it for a little while). I did add some hydraulic fluid today but I'm pretty sure I didn't add too much. I know people say that 90 degree bends like at that point can be a reason for them to get hot but again I never had this problem before that I remember. What should I look at? Thanks for any suggestions!

 

[TheOldHokie]

Today I needed to swap out the backhoe for a tiller and when I was done and needed to reconnect the backhoe, I noticed the quick connect that goes back to the tractor from itself was hot to the touch, so much so that I had to very quickly undo it so I could get the backhoe line back on. Once it was on, and running for a few minutes, the return line from the backhoe got hot too. I smelled it and didn't smell any burned oil smell but it's definitely hot and not something I ever remember when doing this in the past. It was not hot when I went to take the backhoe off initially (even though I had been running it for a little while). I did add some hydraulic fluid today but I'm pretty sure I didn't add too much. I know people say that 90 degree bends like at that point can be a reason for them to get hot but again I never had this problem before that I remember. What should I look at? Thanks for any suggestions!

That does not sound unusual. The coupler is going to get very close to the temperature of the hydraulic oil.

Dan

 

[analog]

That does not sound unusual. The coupler is going to get very close to the temperature of the hydraulic oil.

Dan

Any particular reason why that is the only fitting that's getting hot though? All the rest of them are cool to the touch.

 

[Mark_BX25D]

That indicates a restriction at that point.

I don't know if it's normal or not, though.

 

[TheOldHokie]

Any particular reason why that is the only fitting that's getting hot though? All the rest of them are cool to the touch.

Its the last and smallest one in the continuous flow loop where the oil is the hottest. What others are we comparing it to?

Can you clarify how hot its getting? Just mildly uncomfortable to hold or so hot it will burn you? Any sign of pump loading? How hot to the touch is it? Is this really new behavior or something you just never noticed before?

Dan

 

[analog]

What is pump loading? It's very uncomfortable, if I held it I'm sure I would get a burn, but I would put the temp at maybe 150 degrees if I had to guess.

This is new behavior that I never noticed before when switching out the backhoe, although I can't honestly say that I have taken the backhoe off after running it for a while so I'm not 100% positive it's not always been there. Was hoping someone has a BX25D and could tell me if theirs gets hot too

 

[RCW]

I’ve seen here on OTT that the hydraulic system can get to ambient temperature plus 100 degrees F.
I guess a hot fitting doesn’t sound that unusual.

 

[whitetiger]

What is pump loading? It's very uncomfortable, if I held it I'm sure I would get a burn, but I would put the temp at maybe 150 degrees if I had to guess.

This is new behavior that I never noticed before when switching out the backhoe, although I can't honestly say that I have taken the backhoe off after running it for a while so I'm not 100% positive it's not always been there. Was hoping someone has a BX25D and could tell me if theirs gets hot too

See if the 3 point will raise. If it does not, then you have a defective/failed coupler tip on the back hoe disconnects.

 

[TheOldHokie]

What is pump loading? It's very uncomfortable, if I held it I'm sure I would get a burn, but I would put the temp at maybe 150 degrees if I had to guess.

This is new behavior that I never noticed before when switching out the backhoe, although I can't honestly say that I have taken the backhoe off after running it for a while so I'm not 100% positive it's not always been there. Was hoping someone has a BX25D and could tell me if theirs gets hot too

Oil temps of 150 are a bit elevated but certainly "in range" for extended operation in hot ambients. Pump loading refers to conditions where the pump is pumping against overly high pressures in the power beyond loop. This is a situation where the temperature is a pretty subjective judgement. Its going to be hot - just a matter of (pardon the pun) degree.

Dan

 

[analog]

See if the 3 point will raise. If it does not, then you have a defective/failed coupler tip on the back hoe disconnects.

The 3 point does raise. It's what I was using before I went to go hook the backhoe back up.

 

[analog]

Oil temps of 150 are a bit elevated but certainly "in range" for extended operation in hot ambients. Pump loading refers to conditions where the pump is pumping against overly high pressures in the power beyond loop. This is a situation where the temperature is a pretty subjective judgement. Its going to be hot - just a matter of (pardon the pun) degree.

Dan

I'm sorry for my ignorance, but other than an obstruction in the line, what other potential problems would cause high pressures in the system?

 

[whitetiger]

The 3 point does raise. It's what I was using before I went to go hook the backhoe back up.

Did you try the 3 point after you reconnected the backhoe?

 

[58Ford]

How hot? Just a suggestion:

12:1 Infrared Laser Thermometer

Amazing deals on this 12:1 Infrared Laser Thermometer at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

It might surprise you how often you use a temp gun if you have one!

 

[TheOldHokie]

I'm sorry for my ignorance, but other than an obstruction in the line, what other potential problems would cause high pressures in the system?

None that I can think of.

But lifting loads is an obstruction that causes high pressures and heats the oil. Small hoses and couplers like the ones on your tractor are obstructions which introduce pressure drops and increase flow rate which heats the oil. That is the nature of any hydraulic system.

That coupler is the last one in a series of heat producing sources so it is going to get warm or even hot to the touch. Your description seems to indicate it is overly hot but that's subjective and hard to judge without a measurement. If you think its a sign of a real problem invest in that infrared thermometer and put a number on it. The upper limit for hydraulic oil temperature is generally considered to be 180F and ideally well below that.. Or better yet put a pressure gauge on the line entering the coupler to measure the back pressure at that point. That and a measured temperature will tell you exactly what the situation is.

Dan