Valve leak down

J_J · Jun 9, 2006

I only have one of those joystick valve, but I have 6 of the electric valves. and two sets of 4 valves. They each weigh about 50 lbs . I have to bring this project to a conclusion real soon. If I use the two sets of four, I will have a lot of handles in front of me to select. Maybe a color code would work.

With the electric valves,I had even thought about a glove with switches on the top of the hand to operate the backhoe like someone opening and closing and twisting their hand. If the hand is straight out, the boom, tilt arm, and bucket would be straight out. When you want to dig, you bend your hand and the boom,tilt arm and bucket follow the movement of your hand. Just don't try and grab your coffee or coke with that hand, no telling what will happen. /forums/images/graemlins/grin.gif Just might reach around and grab you from the rear.

J_J · Jun 9, 2006

I only have one of those joystick valve, but I have 6 of the electric valves. and two sets of 4 valves. They each weigh about 50 lbs . I have to bring this project to a conclusion real soon. If I use the two sets of four, I will have a lot of handles in front of me to select. Maybe a color code would work.

With the electric valves,I had even thought about a glove with switches on the top of the hand to operate the backhoe like someone opening and closing and twisting their hand. If the hand is straight out, the boom, tilt arm, and bucket would be straight out. When you want to dig, you bend your hand and the boom,tilt arm and bucket follow the movement of your hand. Just don't try and grab your coffee or coke with that hand, no telling what will happen. /forums/images/graemlins/grin.gif Just might reach around and grab you from the rear.

Barryh · Jun 11, 2006

Just don't try and grab your coffee or coke with that hand, no telling what will happen. Just might reach around and grab you from the rear.

 /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Can't wait to see the completed back hoe. What projects do you have lined up for it when completed? Do we get to see pictures? /forums/images/graemlins/ooo.gif

Barryh · Jun 11, 2006

Just don't try and grab your coffee or coke with that hand, no telling what will happen. Just might reach around and grab you from the rear.

 /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Can't wait to see the completed back hoe. What projects do you have lined up for it when completed? Do we get to see pictures? /forums/images/graemlins/ooo.gif

menchhofer · Jun 11, 2006

I am with the rest of you. I always thought the valves should keep the bucket/loader up no matter how long.

However, I just purchased a Kubota Z21 and noticed when I raised the mower deck and shut off the engine, the deck eventually goes down again by the next morning.

Kubota dealer says this is a safety feature on the mower and is normal.

So I would assume it is also a safety feature on the PT even though sometimes it can make a job more difficult/time consuming......

MuncyBob · Jun 11, 2006

The belly mower on my old Farmall will do the same thing, but it does take longer than the PT does.

Spiffy · Jun 12, 2006

You must consider this subject as a safety concern. What if you leave that bucket in the raised position, and your children happen to be playing around the PT. One of them just touches the joystick. Never leave your lift arms up. Always lower implements to the ground, and remove the key.


I definitely agree [though, on the farm, seldom practice /forums/images/graemlins/blush.gif - of course, we often use a FEL instead of ladder jacks when painting etc., and I'll claim it's much safer than ladder jacks]. Actually, what I was trying to point out is that unless the pressure is gone before you can dismount the machine, the danger is still there. Leak down over a day rather than two weeks may slightly improve safety by the laws of probability - but just can't replace good practice in the first place.

Therefor, I concluded PT's reasoning must have been economy rather than built in safety. /forums/images/graemlins/crazy.gif

Spiffy · Jun 15, 2006

Looking at my valve block yesterday, I noticed the name was that of [what I assumed anyway] a fairly respected hydraulics mfg.

Maybe they do sell several tolerances - either by manufacturing cost or to customer spec. Though the latter still doesn't make sense to me after being used to valves that [barring days or weeks] keep cylinders where you left them. On that same note, my line of thinking says that if the 1 & 2 prefixed machines are commercially targeted, PT would have called for "tight" valves of those, even if they thought it necessary to have fast leak down on the lighter ones. /forums/images/graemlins/confused.gif

With rather low [vertically, not weight] lift requirements, perhaps the mining industry wouldn't take notice, but I'd somehow imagine them wanting very tight valves. /forums/images/graemlins/confused.gif

KentT · Jun 15, 2006

If cylinders didn't typically do this, why would they sell special check valves to prevent this from happening?

Every hydraulic cylinder I've used will bleed down over time -- some faster than others...

J_J · Jun 15, 2006

Some valves have load checks built in. They cost more of course. How do you know if it's the cylinder leaking down, or the valve. I posted a post describing how to check if the cylinder is leaking. I believe it was in May. I state again, a good valve or a good cylinder should not leak down except over time. I mean weeks not hours.

They sell these external check valves for old valves that leak down to fast, or you just want a positive hold, like when someone is working under a backhoe bucket, or lifting stacks of plywood up to the second floor.