2wd LO revisited - will this work?

[Sticks]

#ad




I acquired this 12v solenoid (bake unit for a skid steer) a while back. The picture shows the 4 ports and the flow through them when the power is both on and off. Will this work for a home brew redneck shade tree kit to get 2wd low range?



If so, who needs to get hooked up to what. I was hoping to mount this on the frame rail above the front axle and re-route the red and black vacuum hoses there.



Thanks in advance!

 

[bighammer]

Looks like it would work fine. Use one side for the vaccuum (say the blue from the top) and the other for a vent (red on side) then the 2 lowers can go directly to the axle shift motor.



You can by-pass all the lines going to the transfer case as long as you make sure that you engage your transfer case first, then lock the axle.

 

[Sticks]

So let me see if I understand you.



Red hose connected to the blue line in the no power diagram, and black hose to the red line.



Or is it just hook up what ever hose is the vacuum to either, and plug or filter the other two ports.



If I hooked up both lines to the solenoid, thus reversing the hookup to the axle when activated, would the vacuum actually work to keep the front axle disengaged, or do I risk damaging something or defeat the purpose?

 

[Bob V]

First, it depends what kind of valve it is. Some pneumatic solenoid valves will not work for vacuum application unless they have a air pilot, usually 40psig. For a solenoid valve to work in a vacuum system it needs to be a direct acting or solenoid pilot. That means the solenoid directly moves the main spool or popet. The solenoid has only a few oz's of force and can not move a larger valve. What most of the solenoid valves do is shift a small valve in built into the solenoid which directs air pressure to shift the main spool or popet. Bighammer is right, you could hook if up so that it bypasses the stock control valve on the transfer case but do NOT engage the valve when moving and the transfer case in 2WD. Big gear clash at the CAD. The other way is to hook it up so it shuts off the vacuum to the hole CAD system. The problem with this is that the down stream side of the valve must be vented when the valve is closed, and it does not supply vacuum to the disengage side of the CAD. This style must also be switched into 2WL before the transfer case is shifted into 4WD for you to have 2WL. I use a vacuum operated 4 way spool valve to control the CAD. With this set up the transfer case valve is used as a 3 way valve, in series with another 3 way valve (2WL switch) to control the front axle CAD. That way the transfer case has to be in 4WD AND the 2WL switch booth have to be "on"for the CAD to shift. You can't shift the CAD in unless the transfer case is in 4WD and when it is in 4WD you can shift the CAD in and out with the 2WL switch ( I call it a switch but it is actually a small valve that looks like a toggle switch, my kit do not use solenoid valves). I hope this helps

Bob V

 

[Sticks]

The valve that I have is a 12 volt hydraulic valve that was intended to be part of the emergency/parking brake for a skid steer, and since the unit is designed to set the brake when the power is off, it has a real good duty cycle. If it can function under a couple hundred psi of hydraulic fluid, it should work under the vacuum that the truck runs.



Maybe I should approach this another way.



Who knows what the function of the Red and Black vacuum hoses is on the front axle 4wd assembly?



Emjay Engineering's 2 low kit shows a solenoid that has four ports on it and connects to both of the vacuum lines by the transmission above the cross member that supports the transfer case (I presume these are the same lines that run uninterrupted to the front axle)



Bob V,



I know that you sell a well made 2 Low kit for the trucks. I talked to you earlier this year about them, but $$$ is as ever and issue with me, and since the solenoid valve that I have is one of those "Here, you want this?" kind of things, I was hoping that I could make it work.



I am familiar with Mike R's home kit and instructions that only require cutting off the vacuum supply to the 4wd Assembly by tapping into the vacuum hose from the firewall under the hood. This valve is a bit big to mount under the hood, and since it has the four ports on it, I was hoping to try one of the different methods.