Curl Cylinder Pressure Readings Low

[Scotty Dive]

I recently broke one of the cylinder curl/tilt rods on my VTek Loader and when I replaced it, I installed a temporary pressure guage so I could measure the system pressure. I have always felt that the curl strength was weak on this loader. Here is what I did to test the pressures:

I cycled the curl cylinders (completely up and down) about 15 times to get any air out from the cylinder change. Then, putting the bucket in the fully curled down position I recieved a pressure reading of ~2100 psi - which is about where it should be. When I cycled the curl bucket all the way upwards, I never received a reading over 600 psi. The loader valve is a joystick made by BLB with no float or power beyond.

Did I test it correctly? If so, why the low reading on the up and not on the down?

 

[J_J]

Did the relief activate at the 2100 psi.

Did the relief activate on the curl up.

If you assume the cyl are good, then the valve spool is leaking bad.

Put the bucket about waist high and tilt the bucket full up, then remove the base hyd hose, and continue to curl up. If fluid is pouring out the base end port, then the seals are bad.

To check the valve spools, switch the hoses on the curl cyl and the lift cyl.

 

[Scotty Dive]

Did the relief activate at the 2100 psi..

I believe so, but I am not sure I know what it sounds like - the engine did labor a bit everytime it hit that 2100 psi

Did the relief activate on the curl up..

There were no engine sounds or anything to indicate it did like when the bucket was fully down

If you assume the cyl are good, then the valve spool is leaking bad.

Put the bucket about waist high and tilt the bucket full up, then remove the base hyd hose, and continue to curl up. If fluid is pouring out the base end port, then the seals are bad.

To check the valve spools, switch the hoses on the curl cyl and the lift cyl.

I can do that....will try that this weekend

 

[Scotty Dive]

In a stroke of genius caused by my own stupidity....I started thinking....that shouldn't I measure the pressure on both sides of the cylinder????

When I moved the guage to the other cylinder port...whammo - 2100 psi. the 600 psi must be the back presssure the cylinder see's when on the return side.

So....looks like the valve and the system are working correctly....

 

[J_J]

A wise move would be to install a gage in the IN port of the FEL valve and the you can
see what the pressure the hyd system is developing at any time the tractor is running.

You might be surprised at how little pressure is required to lift some objects. Once mounted, you won't have to look for the gage, as it is always on the tractor.

 

[Mike476]

I was going to ask where you had placed the gage, glad it worked out.

 

[J_J]

There are valid reasons that you may see 600 psi when raising the bucket when there is no load or light load. However if you hold the lever to the max, the relief should come on and then it would read the max available pressure.

 

[Scotty Dive]

Took JJ's advice and installed a pressure gauge on the pressure in near the loader valve and now I can see all of the pressure readings...everything is working as it should - guess my loader curl is just weak by design

JJ- I do have a questions - I think I still need to adjust my three point hitch some but when it was in the full up position and still calling for pressure and I used the curl cylinder - my pressure readings went way past the 3000 psi my gauge reads...how come?

 

[J_J]

Someone else 3pt did the same thing about a month ago with high pressure on the 3pt. However, the 3pt relief should have relieved the pressure.

It really does not make sense as the fluid to the 3pt is cut off for the time the curl cyl is using the fluid. Any fluid from the loader cyl should go to tank. There should be no pressure on the 3pt when you curl.

When you take the curl cyl to relief, does the 3pt still have pressure?

Someone had mentioned something about the curl cyl regen not flowing out the OUT port, and adding to the pump flow through the system. Maybe cyl intensification.

No one has figured out about the high pressure at the 3pt yet.