Thread: Vacuum to mechanical diff lock conversion

Originally Posted by faceman

good day, may i ask what type of switch is it? i think i will be needing the CDL of my LT95, what do you call this type of switch and where is it originally used?

thanks in advance

HI,

Contrary to what was said in the previous post, I tried the three port option but that only works in a positive pressure environment (pressure switch) and not a negative one (vacuum switch). The fourth and fifth ports are required to allow the air to be sucked in and without those there cannot be any air movement when the vacuum is actuated. The pipes come from the transmission so nothing new there and the fittings and air filters came with the switch (separate purchase but not expensive). The filters are important, don't omit them because the vacuum sucks air into the switch from outside.

It works very very well, better than the original actually. There is no power required in this by the way. That makes it simpler. The little picture on the side is very helpful because it shows the air pressure directions in the two positions available, so you get the pipes in the right order.

Also, I would say that two extra holes is not overkill, having a solenoid operated switch is

Anyway, back to your question. If you look at the photo you will see that the name and model are printed on the side. That is AZ Pneumatica model 521-TT (it's an Italian brand, very good quality). I bought it from the local air control specialist for much less than the cost of a replacement part.

I bought it from:
Westec Automation
2A Winston Pl Henderson Auckland 0610
+64 (0)9-838 4972

Of course that may not be any use to you unless you are in NZ.

Thanks, i'll be searching online where i can buy the part and have it sent to me here in manila, philippines.

I would send them an email and ask how you can buy the necessary equipment of perhaps there is a local air control supplier you can buy through?

AZ Pneumatica S.r.l. - home page

Originally Posted by disco2hse

Goodness me no. I was just responding to the OPs request for info. I was investigating options because my vacuum switch wore out and getting a new one was next to impossible second hand and at a reasonable price. A new one is just a stupid price

FRC5656-DIFF-LOCK-CONTROL-VALVE-SWITCH

Instead I replaced the vacuum switch with this (and put it on the proper side of the gearbox tunnel). 1/10 the price.

Another option is the clippard minimatics switches that Maxi-Drive used. In fact if you have some old MD locker bits laying around you may already have one. They are very small so can easily be panel mounted behind the dash or the seat box. When I priced them a few years ago they were ~$100 from clippard.

My vacuum actuator died today after the first decent track its driven since the 4bd1/lt95 was fitted.
CDL engaged/disengaged a few times happily, then after an extended time engaged - wouldn't disengage. Did all the usual things to remove any transmission windup, but couldn't get it to disengage. Worked out that the actuator is leaking internally - presumably the diaphragm is stuffed.
Removing the front prop shaft for the drive home was the easiest option once I'd worked out the cause.

Apart from finding this thread with lots of useful info, I also found these replacement diaphragms at Les Richmond Automotive.
Diff Diaphragm

Anyone fitted one or heard anything about them?

Steve

Originally Posted by clubagreenie

Thats probably a bit overkill. But only because theres extra ports. You only need 3 ports, one each to each side of the actuator and one for the vacuum source.

Norgren and SMC pneumatics would be ther place to start, they will have something. Even use a electic solenoid operated one.

One of these, Norgren Webstore - Norgren Motion Control, Fluid Control Equipment. Pneumatic Actuators, Pneumatic Valves, United Kingdom



These are great little valves, available, N/O or N/C and 12VDC. compact and easy to fit somewhere out of the muck. What about doing away with the diaphragm and using a mini cylider for linear actuation? If someone can work out the amount of movement (push/pull diatance) required then I can work out a cylinder. Then you could run it off either pressure or vac. You could even start with vac and upgrade to pressure if you fit a compressor later.

The vac unit can be cut away from the main body, so you just leave the shaft with the threaded hole in the end.

I'm also working on the D2 actuator using a cylinder to operate from pressure, just need to find out what the movement of the lever on the actuator on the D2 tfr is (anyone?).

If anyone's interested and can get me the push/pull distances I can look into cylinders and also put together a kit of the solenoid valve/switch/hoses for vac operation of the std unit or plus cylinder as an option for pressure operation.

You need 4/5 port valve to allow the relief of built up vacuum in the system, 3 port won't cut it

Originally Posted by steveG

My vacuum actuator died today after the first decent track its driven since the 4bd1/lt95 was fitted.
CDL engaged/disengaged a few times happily, then after an extended time engaged - wouldn't disengage. Did all the usual things to remove any transmission windup, but couldn't get it to disengage. Worked out that the actuator is leaking internally - presumably the diaphragm is stuffed.
Removing the front prop shaft for the drive home was the easiest option once I'd worked out the cause.

Apart from finding this thread with lots of useful info, I also found these replacement diaphragms at Les Richmond Automotive.
Diff Diaphragm

Anyone fitted one or heard anything about them?

Steve

Never have, just resused old stuff laying around, but I'd personally be inclined to keep the vac system, I like it, its simple and works well and is quite relaible with good components

I've fitted the spare one that I had in the shed, and also have a replacement diaphragm coming from LR Automotive to repair the stuffed one. The last of their stock and no more in the future.

The one that failed had a 25mm tear in it - so no wonder it wouldn't work.

I quite like the vacuum system too (although I did say a few negative words to it yesterday). Now that I've actually pulled one apart - I can see it would be quite easy to prise open and remove the front chamber so you could move it manually if it failed on a trip.

Steve