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Electronic actuated CAD

3K views 39 replies 7 participants last post by  Digger84 
#1 ·
Yeah, so a discussion in another thread brought us to the topic of having a stock vacuum actuated CAD (Central Axle Disconnect) operated off an electronic solenoid to control the CAD rather than the switch on the Transfer Case, and having a rocker in the cab to control the disconnect.

I personally run the cable disconnect and have had zero issues, but I like to screw around in the garage rather than watch TV so I grabbed a switch off Amazon and some vacuum line. I can probably figure out a decent way to run the rocker switch, wiring, vac lines and solenoid switch. But I'd like to spitball some ideas on what to place where so it doesn't interfere with axle articulation or generate mile of vacuum lines.

I pulled out my old CAD and checked it out so it is working as it should, so while I'm goofing around with all the parts if anyone has any Ideas to throw my way, I'm all ears.

Keep in mind this is just an experiment on making it work, not an endorsement for any of the three schools for locking the front axle. (Solid, Vacuum, Cable) so please don't Bash on me harshly.

A couple reasons brought up for this.
1. 2W low on pavement
2. Issue with the transfer case.
3. Accessability for service in snowy climates
4. Lock or unlock at will on the trail without disengaging TC

Now open for suggestions...
 
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#2 ·
Sounds like a bunch of unfounded dreaming LOL

firewall higher than distributor cap would be my choice of mount location...
 
#3 ·
^Agreed, thinking of placing valve in tandem with 4wd light vacuum switch, wiring with main harness loom across firewall into cab. Neat and clean
 
#4 ·
Also would take advantage of stock vacuum supply off manifold to valve.
 
#5 ·
#6 ·
Would still need the solenoid valve to reverse it so might as well just use engine vacuum...
 
#7 ·
Not necessarily... I was thinking you would just use two of those pumps, one connected to each side of the actuator, on a 3-way switch (1-off-2) so that only one could be actuated at a time.

These pumps are tiny too and could easily be hidden on the frame rail and they can’t be more than $5 at the Pick A Part places.

Of course, I run twin E-lockers and hubs, so this is nothing but a fun mental exercise 🙂
 
#8 ·
You would need a way to break vacuum on the side of the pump that was not running... otherwise it might take a day or two to achieve full engagement or disengagement...
 
#10 ·
If I'm not mistaken, they have an internal vacuum break - these are used to actuate the hubs on the Super Duty D50/60 axles and are basically plumbed directly from the pump to the hubs (tee'd off from one pump to both front hubs).
 
#9 ·
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#11 ·
Nope... I happen to have a superduty... the vacuum pump goes to a vacuum reservior and a vacuum solenoid valve controls the vacuum signal that locks and then unlocks, both w vacuum.... It's a goofy system

The pump receives power when ign is switched on and runs until it builds enough vacuum to shut off via it's onboard vacuum switch.... then when 4x4 is selected the actuator valve ises the vacuum reservior to lock the hubs and again to unlock them when going back to 4x2
 

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#13 ·
Ah, that is interesting! The '03 I stripped for my 60/10.5" axle set did NOT have that setup at all and was exactly as I described below. In all fairness, it was a fairly beat up Forest Service truck so who knows what they did to that thing, I just assumed it was stock since it was being used daily by the Rangers up in the hills... thanks for posting! :)
 
#12 ·
HA looking at the pic I just posted, I just noticed that my hub actuator solenoid is still unplugged... I unplug it when parking my 20k lb fifth wheel trailer in 4x2 LOW range lol
 
#14 ·
So I've played around with a couple valves off Amazon 3 way and 5 way, I get enough vacuum to keep the collar solidly in the unlock position, but I can't seem to get either Valve to divert completely to fully engage the 4wd side for a solid lock into 4wd.

Any thoughts?
 
#15 ·
Show us how you plumbed it

If it were me I'd be using 2 3-way valves

It's late and I'm tired but here's a quick sketch

Edit: I didn't draw it in but it's mandatory to have a check valve between the engine and the solenoids... the factory cad has one and you can simply T in after it if it's still in place.
 

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#17 ·
On This project we are shooting for a couple wires through the firewall rather than vacuum or cable, But thanks for the suggestion.
 
#18 ·
I hooked up this switch for a test and it worked just fine. This is the same valve as the 12V actuated one. One vacuum line in, port 1, 2 is CAD disengaged and 4 is CAD engaged. 3 and 5 are vent ports.
 

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#19 ·
That's where I'm at with this 5 port, except the electronic end of the switch is not redirecting the vacuum when energized no matter which way I run the ports. The 3way does open and close but doesn't port over, suggesting two valves, one normally closed, one normally open, that would reverse the direction when energized.

I did find a Mitsubishi Dual vacuum valve I'm gonna give a shot whenever it shows up.
 
#21 · (Edited)
I think, you think to complicated. There are only 2 ports on the CAD. With this switch, you select either one and it stays there till you switch again.

Also, show me the diagram on the valve, then I can tell you if it works or not. Deal with this shi... every day.

I had this at work. I think it is from McMaster. Part Number 61345K75
 
#22 ·
Manny, here's the 2 way 5 port, the other was a two way 3 port, already on it's way back to amazon.
 

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#23 ·
You need a 4 way 5 port solenoid. Look at the picture and think the cylinder is the CAD.
 

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#24 ·
Except it is a vacuum system the manifold is such an abundant source (consumer of air) you don’t need return vacuum and to shut off you return to outside pressure which is limitless so you don’t need return lines just vent which really means letting outside air into the system and the availability of outside air requires no routing as it surrounds the entire system


Sent from my iPhone using Tapatalk
 
#25 · (Edited)
Just talked one of our engineers about those valves. Most all of them require pressure to move the spool inside the valve to switch over.I think we need to find special vacuum valves as the air valves do not work with vacuum unless the spool is mechanical connected. Found the solution...

https://www.oldairproducts.com/product/3-port-vacuum-solenoid-25-1020
 
#26 ·
I found out the key word in searching was "Direct Acting" for what I was looking for. Just cant find one yet that suits my fancy. Manny, your link isn't opening for me right now, have to check it out later.
 
#27 ·
Here's a screenshot of his link
 

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#28 ·
So the Mitsubishi valve Dual valve setup looks to be a winner, One valve normally open, One normally closed. they fully open without any airflow to work the pilot, energizing them in tandem off the same circuit will give me immediate vacuum reversal, Bench tested fine, Now just got to wire and plumb them up. Sorry pic loaded upside down, but that's the valve setup.
 

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#30 ·
My Mitsubishi valve works perfect once I got it vented right. Excuse the spaghetti, I just had to see it work....

 
#31 ·
Looks like you got it at last!

To add to your dialogue in the video... OR if you want to keep the t case switch but be able to override it w the flip of a switch for 2 low.
 
#32 ·
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