Loader "Relief" valve?

[BufordBoone]

I've read a few posts that refer to a "relief valve" kicking in on a loader if you try to lift a load that is too heavy or travel rough terrain with a heavy load on the loader.

Last summer I had to move a lot of heavy logs. I found a few drops of hydraulic fluid under the tractor the next day, found some wetness below where the loader quick connects are located. I checked every fitting I could find, none were loose. I thought I'd monitor the situation and it did not reoccur.

This weekend I moved a lot of gravel. A few times I tried to scoop too much and the loader would not pick it up (rookie mistake, but hey, I admit to being a rookie).

Today I found a few drops of fluid under the tractor and wetness in the same spot as after moving logs.

I'll check fittings again but wanted to ask this group if it believes a reasonable explanation is that I tripped my relief valve.

It makes sense to me...but I know I'm a rookie.

Thanks for any help you can provide.

 

[Dave M7040]

I've read a few posts that refer to a "relief valve" kicking in on a loader if you try to lift a load that is too heavy or travel rough terrain with a heavy load on the loader.

Last summer I had to move a lot of heavy logs. I found a few drops of hydraulic fluid under the tractor the next day, found some wetness below where the loader quick connects are located. I checked every fitting I could find, none were loose. I thought I'd monitor the situation and it did not reoccur.

This weekend I moved a lot of gravel. A few times I tried to scoop too much and the loader would not pick it up (rookie mistake, but hey, I admit to being a rookie).

Today I found a few drops of fluid under the tractor and wetness in the same spot as after moving logs.

I'll check fittings again but wanted to ask this group if it believes a reasonable explanation is that I tripped my relief valve.

It makes sense to me...but I know I'm a rookie.

Thanks for any help you can provide.

Yes the relief valve operates if you try and lift too heavy a load in order to protect the hydraulic pump. However, once the control lever(s) are released, the hydraulic fluid is trapped in the cylinders and, in many instances, there is no additional safety valve to deal with increased loads caused by driving and bouncing, pushing with a full bucket.

Your relief valve, unlike the one on your hot water tank, dumps back into the tank or reservoir so you don't loose any fluid. The relief valve is constantly opening and closing as you operate the FEL. Just make certain that your hoses at the quick couplers are not pulling at an angle when you are working hard. Otherwise I would not worry.

Dave M7040

 

[/pine]

I've read a few posts that refer to a "relief valve" kicking in on a loader if you try to lift a load that is too heavy or travel rough terrain with a heavy load on the loader...
...This weekend I moved a lot of gravel. A few times I tried to scoop too much and the loader would not pick it up (rookie mistake, but hey, I admit to being a rookie).

On a side note...
I suspect that when the relief valve was kicking in you were trying to lift more than a bucket full...i.e., gravel on top of the payload or even just above a tooth bar if you have one...an OEM FEL bucket should not have any trouble lifting a full heaping payload of just about any type of gravel etc...

Leaking QD's can often be fixed with new o-rings...replacing the QD's is a bit more expensive...Good Luck..

 

[BufordBoone]

Thanks for the info. What a great resource this place has turned out to be.

 

[Texasmark]

Yes. The valve is usually set a few hundred # (for a number) above the lift rating....at the rated lift point in the loader spec. When you try to pickup an overload, it will just stop trying to lift when reached.

The fact that you are seeing some seepage that you normally don't see is self explaining. You didn't list the year model or operational hours of your machine. On new ones, they don't leak....if it bothers you , might change the orings in the hyd QD connectors.

 

[Oldoak]

OEM FEL bucket should not have any trouble lifting a full heaping payload of just about any type of gravel etc...

All depends on the size of the O.E.M. bucket that was ordered with the tractor.
Just like most situations involving tractors and equipment, there are almost always numerous scenarios.

 

[BufordBoone]

The fact that you are seeing some seepage that you normally don't see is self explaining. You didn't list the year model or operational hours of your machine. On new ones, they don't leak....if it bothers you , might change the orings in the hyd QD connectors.

I checked all fittings and found one that, while not loose, was not difficult to tighten (except for its location). Based on the dampness of the hose cover, I think this was the culprit.

I tightened it up and will check to see if everything is back to normal.

Why is it always the most difficult one to reach that requires tightening?

Thanks to all for the assistance.

 

[Texasmark]

I checked all fittings and found one that, while not loose, was not difficult to tighten (except for its location). Based on the dampness of the hose cover, I think this was the culprit.

I tightened it up and will check to see if everything is back to normal.

Why is it always the most difficult one to reach that requires tightening?

Thanks to all for the assistance.

Why? I say it's because of Murphy's law.....if anything can do the worst of whatever possible, it will. etc. My current PO is cords and hoses......if there is any way possible for them to get hung on something when moving about they will......remids me of grappling hooks mountain climbers use in the movies to get to the top of a cliff and attack an opponent......several tries and it still doesn't grab. That must be ML in reverse. Grin.

 

[Groo]

All valves have a main relief that protects the pump. Some valves have port reliefs or shock valves on either side of the work section that can limit an individual function direction to a lower level than a main relief. This might be used in cases where the cylinder would buckle under full system pressure. Another usage would be for a lower pressure cylinder like a telescopic, or something like a motor.

 

[chriswheeler]

The dealer that installed the Koyker 160 loader on my first tractor ( Yanmar3000 ) set the main relief valve to lift early, it wouldn't lift a full bucket of crushed rock. I tried to lift the front end of the tractor as a load test, loader failed to lift the front of the tractor off the ground. I adjusted the main relief valve on the loader so the bucket would lift the front wheels off the ground. That worked out to also lift a full bucket of 3/4 crushed rock as well. Easy adjustment to make. Can't say if it was proper or safe, but it did work well and didn't damage the loader. In hind sight, think the dealer that installed the loader, set it to relieve early as a safety precaution, but it could not lift a full bucket ( 5' ) and I was sure that Koyker built it to do that and more.
Chris