Thread: Pneumatics

The maxis half in my pos are (apparently) set up to run off pressure rather than vacuum.

I've got all the uninstalled airlines labelled as they came off the actuators, valves and the compressor, which is one of those little blue ARB things.

Not sure why the system was set up like this in the donor.

DL

probably not suitable for the refreshed OP, i was exchanging emails with Warren from MR Automotive and in theory you should be able to use an electronic switch to operate the current generation valve body set up that MR use. I haven't worked through the wiring schematic yet to do it but plan to replace the pull push switch that MR sell in their kit with a D2 type dash switch that is sold by Mulgo and others that fit the Puma defender dash.

This forum is great all the help. Thanks folks

Gromit, the Maxidrive uses a double acting cylinder actuator and isn't spring loaded, I'm not sure how I would plumb in a single 3/2. I need vacuum to engage and disengage.

Roverlord, I'm not overly hung up on either way. I would prefer elec over pneumatic just to keep the clutter away from the dash, its bad enough with the stock wiring as it is. Equally I'm not sure how the solenoids will hold up to Isuzu diesel vibrations???

350RRC, pressure activation ? Thats interesting, I thought all Maxidrives were vacuum operated. I don't have a fixed compressor mounted in the car and would prefer to stick with vacuum just to reduce the potential points of failure.

MLD, that's interesting, I'll give them a call and see if they'll sell just the solenoid.

Cheers

Originally Posted by Zcoota

Gromit, the Maxidrive uses a double acting cylinder actuator and isn't spring loaded, I'm not sure how I would plumb in a single 3/2. I need vacuum to engage and disengage.

Apologies, I'm not familiar with how the Maxidrive works so if it's effectively a double acting cylinder to operate then yes, you need a 5/2 valve but if you are running it on vacuum the valve needs to be directly actuated. Vacuum to port 1, locker connections ports 2 & 4. Ports 3 & 5 are exhausts but rather than blowing air out they will suck air in so you'd need a couple of silencers to act as filters.
You could use two 3/2 valves per diff, one normally open and one normally closed operated together but it's starting to get messy.
You could also run a 5/2 with auxilliary pilot air, this means connecting compressed air to the solenoid end. Again getting messy.

There aren't many companies that offer directly actuated 5/2 valves Clippard is one possibility, they will also have 5/2 manual valves that are directly operated.

You could probably, as mentioned, run it on compressed air but I'm not sure of the seals that were used in the Maxidrive 'cylinder'. If 350RRC has this setup then it can be done but you might need a pressure regulator as +10bar vs. whatever vacuum level you normally achieve is a big difference.



Colin

Originally Posted by gromit

Apologies, I'm not familiar with how the Maxidrive works so if it's effectively a double acting cylinder to operate then yes, you need a 5/2 valve but if you are running it on vacuum the valve needs to be directly actuated. Vacuum to port 1, locker connections ports 2 & 4. Ports 3 & 5 are exhausts but rather than blowing air out they will suck air in so you'd need a couple of silencers to act as filters.
You could use two 3/2 valves per diff, one normally open and one normally closed operated together but it's starting to get messy.
You could also run a 5/2 with auxilliary pilot air, this means connecting compressed air to the solenoid end. Again getting messy.

There aren't many companies that offer directly actuated 5/2 valves Clippard is one possibility, they will also have 5/2 manual valves that are directly operated.

You could probably, as mentioned, run it on compressed air but I'm not sure of the seals that were used in the Maxidrive 'cylinder'. If 350RRC has this setup then it can be done but you might need a pressure regulator as +10bar vs. whatever vacuum level you normally achieve is a big difference.



Colin

Hi Colin, Ok, that makes sense. I've been on the phone and seem to have zoned in on a MAC value (45A-GC1-DDBA-1BA) which seems to be a 4/2 double solenoid affair. I think the Maxi-drive kits these days include a spring loaded 4/2. From what I've dug up it seems that the spring loaded can cook if left on for a while, not sure how true that is. The 4/2 double solenoid seems to be a clone of the OE Nissan one use in the factory diff locks.

Originally Posted by gromit

Apologies, I'm not familiar with how the Maxidrive works so if it's effectively a double acting cylinder to operate then yes, you need a 5/2 valve but if you are running it on vacuum the valve needs to be directly actuated. Vacuum to port 1, locker connections ports 2 & 4. Ports 3 & 5 are exhausts but rather than blowing air out they will suck air in so you'd need a couple of silencers to act as filters.
You could use two 3/2 valves per diff, one normally open and one normally closed operated together but it's starting to get messy.
You could also run a 5/2 with auxilliary pilot air, this means connecting compressed air to the solenoid end. Again getting messy.

There aren't many companies that offer directly actuated 5/2 valves Clippard is one possibility, they will also have 5/2 manual valves that are directly operated.

You could probably, as mentioned, run it on compressed air but I'm not sure of the seals that were used in the Maxidrive 'cylinder'. If 350RRC has this setup then it can be done but you might need a pressure regulator as +10bar vs. whatever vacuum level you normally achieve is a big difference.



Colin

Thanks for your expertise Colin.

The bits I have that were part of a complete working system include the original Maxi valves as well as the actuators.

From memory there is a pressure regulator either on the ARB compressor or next to it and that's it.

The PO was also using the same compressor for a plug in airline for the tyres, also ARB. He used to work there.

cheers, DL

Originally Posted by Zcoota

Hi Colin, Ok, that makes sense. I've been on the phone and seem to have zoned in on a MAC value (45A-GC1-DDBA-1BA) which seems to be a 4/2 double solenoid affair. I think the Maxi-drive kits these days include a spring loaded 4/2. From what I've dug up it seems that the spring loaded can cook if left on for a while, not sure how true that is. The 4/2 double solenoid seems to be a clone of the OE Nissan one use in the factory diff locks.

A 4/2 is exactly the same function as a 5/2 just with one less exhaust port.
Most solenoids are continuously rated so odd that it cooks but using a bi-stable valve (double solenoid) solves the problem you just need a momentary signal to each coil to get it to switch. Problem then is how do you know whether it's ON or OFF. With a single solenoid you can wire to an LED to show the locker is ON.
Coil voltage range is listed as 12V -15% to +10% so max voltage is 13.2V, maybe it's the voltage that kills them ?

I work for a company that's a competitor to MAC, we don't have a 5/2 directly actuated valves because there is little demand. There must be a demand in the US because several American companies make them.

Colin

Originally Posted by gromit

A 4/2 is exactly the same function as a 5/2 just with one less exhaust port.
Most solenoids are continuously rated so odd that it cooks but using a bi-stable valve (double solenoid) solves the problem you just need a momentary signal to each coil to get it to switch. Problem then is how do you know whether it's ON or OFF. With a single solenoid you can wire to an LED to show the locker is ON.
Coil voltage range is listed as 12V -15% to +10% so max voltage is 13.2V, maybe it's the voltage that kills them ?

I work for a company that's a competitor to MAC, we don't have a 5/2 directly actuated valves because there is little demand. There must be a demand in the US because several American companies make them.

Colin

Thats a good point about higher voltages cooking the coils, I didn't consider that. My other concern about the bi-stable solenoids was what locks them in position ? If only momentary power is needed to activate them, once the power is removed, what's stopping them from vibrating into the other state ? Or am I starting to overthink this ?

A cool feature of the Maxi-drive is a switch inside the pneumatic actuator that shows when its full engaged.

So Colin, I don't suppose I could buy the solenoids and other bits of plumbing I need through you ?