Hydraulic valve question

[ShawnAgne]

Ok finally got around to putting on the tandem valve that a previous thread was about. In order to prevent dead heading I backed the pressure valve off all the way. Here is the question 500lb is the lightest it will go, is that still enough to operate the Cub's hydraulic system? I'm wanting it set as low as possible, so I was trying to kill the system and then bring it back high enough just to work.

[Crimson Tim]

It will operate depending on what load you expect it to carry. I think I have seen on here that the standard Cub hydraulic system normally operates at 1200 psi?

[John *.?-!.* cub owner]

Your valve needs to be an open center so that when the valve is in the center position the fluid simply flows through it with no restriction allowing normal use of the touch control. At that point the fluid has no restriction until the touch control is operated. If I remember correctly, the safety valve in the touch control is designed for 1500 pounds, with 1250 pounds being the pressure it runs at lifting a load. If you have an open center valve, your pressure relief can be safely set for 1500 the same as the touch control. The safety valve of the external valve is designed to only come into play if the load is such that it takes more than 1500 pounds to lift, it is NOT intend to serve as a bypass when the external equipment is not being used.

[ShawnAgne]

John,

Gotcha I think eventhough the engineer for the valve and another person on here a year ago said the Tandem will work, I'm going to get the open version of it just so I KNOW it will work. Tired of playing around with this and getting hydraulic oil on the garage floor.

Thanks,
Shawn

[John *.?-!.* cub owner]

Before buying another valve verify whether or not the one you have is an open center. With the handles in the center position blow in the oil in port and see if air comes out the return port. If i9t does, it is an open center. Also some valves can be changed between open and closed centers by moving a plug and connecting the return (back to TC) where the plug was removed from.

[ShawnAgne]

John, my valve does what you are describing. However the Tandem valves allows the cylinder to carry a load when in neutral. From reading descriptions an open valve in neutral will not carry a load. So I want a valve that can not carry a load in neutral?

[Smokeycub]

John, my valve does what you are describing. However the Tandem valves allows the cylinder to carry a load when in neutral. From reading descriptions an open valve in neutral will not carry a load. So I want a valve that can not carry a load in neutral?

John has your question covered. Tandem or not (unless I don't know what tandem valves are) , open center spools (valves) are what you want and will hold a load. Generally a 3 position open center spool allows the cylinder(s) to hold when the valve is in neutral (like a loader would hold the bucket up when the valve is released). If your valves don't do that then you need another set. That said, some valves have an optional detent that allows the device to float (no hold) but that normally requires a specific action when engaging that function (similar to kicking in a four barrel carb back in the day), yet holds a load when in neutral.

Tired of playing around with this and getting hydraulic oil on the garage floor

We need to know what exactly is happening that's causing the headaches. It's really not complicated and should be pretty straight forward.

P.S. 1) Is there a possibility (I'm guessing this is not the case) your valves are single action? Single action spools will not hold a load in neutral.
2) Are you using a bypass block on the Touch Control unit?

[John *.?-!.* cub owner]

As Smokeycub stated, when in neutral position the valve simply blocks the high pressure line going to the cylinder so the cylinder will stay where it is, and the pressure from the pump just goes through it to the line going to the TC diverter block, so you should be ok.

[ShawnAgne]

Ok called the company. Their "Open" valves are just for motors. When in neutral it won't hold a load. So if I used their open valve on the blade it would grab the snow then the blade would go which ever way it wants. The only way the blade would hold still is if it was engaged one way or the other. The engineer (who was familiar with the Cub as a family member has one) said the tandem valve when in neutral will prevent the flow and prevent the blade from moving (left/right). What happened was I pushed the control lever forward (without having the blade attached) and this deadheaded the valve and slightly blew oil out where it attaches to the tank. So basically I caused the problem I was having. So think it is solved. Getting new gaskets for the bypass then we should be good to go. Thanks.