Lost CTIS and all air driven stuff ?

[snowtrac nome]

Ok, so just clean. Got it !

you can lube it with air brake grease you can get at your local parts store or vasoline, but only those 2 products, or you can expect failures of the rubber pieces in it

 

[1951M1078]

Took the cover off the unloaded and then it starts pumping. Will pull it apart later and do a cleaning. Funny.

But no air out of the 1/2" line or the 1/4" ? Pulled the regulator off and did not see anything ? Put it back on and tried making a adjustment. Put a wrench on the adjuster and it moved ?
One photo is worth a 1000 words.



So I went with a heal-coil and will retest soon. Anybody know how and what the set point is ?

 

[Ronmar]

It is not a regulator, it is a protection valve. It only allows air out to those 1/2” and 1/4” lines(ctis and cab air suspension) when the wet tank pressure exceeds 85PSI. If the pressure drops that low it stops sending air to those accessories and saves it for the brake system.

You need to remove the drain valve on the wet tank and install a pressure gauge there then set that adjuster so the air stops flowing out of those 2 lines with the wet tank gauge at 85 PSI...

With that gauge in place is a good time to check and set the governor unload pressure when the tank is filled to 120PSI...

 

[1951M1078]

Ok, sorry about the name.

So it closes at 85 psi. Then the tank will build to 120+- psi and pump cut off. right.

Maybe the CTIS will start working ?

 

[Ronmar]

Ok, sorry about the name.

So it closes at 85 psi. Then the tank will build to 120+- psi and pump cut off. right.

Maybe the CTIS will start working ?

The tank will fill to 120 PSI as long as the CTIS and cab air lines are not dumping all the air if those lines are open the tank wont get above 85 psi as the protection valve will send all the air over 85 PSI there.

Right above the protection valve is the CTIS pressure switch. It is open untill the pressure in the tank exceeds 112-115 PSI then it closes. It stays closed till the tank pressure drops to around 85-90 PSI where the switch re-opens. This provides tank air status to CTIS and it is looking for that 115 PSI closure before it will do anything... On my truck, a 3 second shot of CTIS tire inflate will drop the wet tank pressure from 120 to 85 PSI when the tires are at offroad pressures...

 

[1951M1078]

A big THANKS to,Ronmar. Think I am getting how it works . With luck ? LOL

 

[Ronmar]

For your flat tire, this is a simple check for a leaking wheel valve and what it looks like when it leaks.

I had a tire that would slowly loose pressure. With the tire inflated, I removed the banjo bolt and slipped a rubber glove over the banjo fitting and sealed it to the end of the hose line with tape. It only took a few minutes to see the glove start to blow up like a baloon from air leaking back past the wheel valve.

The wheel valves are easy to strip apart and clean the sealing surface...you have to deflate the tire first though...

 

[1951M1078]

Thanks,but think it has something to do with the funny air problem. Have had no problems with the tires staying up until that happened.

 

[1951M1078]

Back at it. Installed a air gauge in the wet tank and tested. Tank stops filling at 134 Psi. Starts refilling at 110 Psi. Need to readjust it stop filling at 122 Psi.

As for the protection valve ? Don't think it is working.

If I understand it right. Their should be no air flow from the valve at the 1/2" and 1/4" lines until the tank is over 85 Psi.

What I did find is their is air leaking around the adjuster screw.(with the lock-nut backed off) Thinking the diaphragm may be leaking ? I don't think their should be pressure behind the diaphragm on the adjuster screw side seems like that would make the valve stop working. No leaking around the housing.

System tried to work but stopped ? I shut off the air to the cab air lift 2 or 3 times (turning it on and off ) then it just stopped working. I checked the 1/4" line at the protection valve and no air with a wet tank at 130 Psi ?

Will get back on to it soon.

Any ideas ?

 

[tennmogger]

You seem to have the problem cause figured out (refer back to post 4 this thread). The OPV/PPV is not working consistently. It should not have air leaking around the adjustment screw. Yes, you probably have a bad diaphragm.
I suggest replacing it. This Over Pressure Valve is available:

Part# N30261B
About $70.00/ea
when I got mine the Lead time was 2 weeks, I had to pay with a credit card so have to call them.

CBT Corporation
816-796-9310
1200 S Powell Rd
Independence MO 64057

If you make a few changes to the output connections to the wet tank you can add a quick connect for an air hose. Then put a QC connector on a pressure gauge as a diagnostic tool to plug in when you need it.

Add a 1/2"NPT "T" and specify swivel connectors for the NPT hardware. That lets you take apart this assembly without having to start at the far end at the 1/2" and 1/4" hoses and all that stuff.

Looks like this:


The pressure setting on the new OPV's I bought were preset at about 85 psi and work fine. BTW, this same OPV is used on Unimog 406, 416, and U-1300 and maybe others. A common part everywhere but the USA apparently.

 

[1951M1078]

Thanks for the address.

Also is this where you installed the shop test line? And could this be a air out also ?

 

[Ronmar]

Yep sounds like the protection valve has issues. Have you disassembled it yet? I think it has 4 small bolts to separate the housing. Sean Fillner did a short youtube video on overhauling one in his Abel LMTV build series. It basically works like the wheel valve just with an adjustable spring pressure via the adjuster to control at what point the air pushing on top of the diaphram opens the valve port. You may have a clogged valve port...

 

[1951M1078]

Two screws and no its not plunged. Can I get just a diaphragm ?

 

[1951M1078]

So as all of you know (now) the housing and the diaphragm were bad. So I repaired the threads in the housing and came up with some diaphragm material to make up a backup to add to the old one.

I reinstalled all of it for testing . Wet tank filled as it should. Air ride system filled and worked . But the CTIS started to work and then did some kind of purge (under the passenger side kick panel) and stopped filling the tires. All lights flickering ? So I added a ground wire to the box and took it to the chassis. Retested it and worked for 1-2 fills then back to a purge and flickering lights. Dumped all the air in the wet tank and retested. CTIS filled for 4-7 times then flicking. Power on a off and back to filling and then one solid light. Not fixed but the tires a filled.

Think I will take a look at the air pressure switch and see if their is a ground problem their ? But still thinking about going manual ?

Their is a fitting on the wheel that after filling was leaking ? Has a slot in it so I pushed on it and it stopped leaking ? Need to find out what its for ?

 

[Ronmar]

Cool, sounds like you are closing in on it. Using your gauge were you able to determine if your patched protection valve was responding consistently? if it isnt, that could be part of the issue(valve closing off air before the switch opens telling CTIS that tank pressure is low)... Could also be your switch is not responding appropriately or going cleanly from a short to an open and vis-versa...

That part in the last pic is a "kneeling" valve. It was used to deflate the tires for air transport. They leak as their seals fail. some have replaced them with a fixed elbow, some take them apart and using coins and JBweld, convert the valve into an elbow

 

[1951M1078]

The protection valve is now working and has been reset. Still need to reset the pump cut out.

Thanks for the valve info. May just JB them ?

 

[Ronmar]

Yea, there are some folks on here who have described how they “fixed” the valves...

 

[1951M1078]

Now I'm testing my new manual CTIS system. Looks like it works but still need to build the housing to put it in. Just laying on the floor is not going to work ? LOL

 

[1951M1078]

Test went well. So I ran the air lines.


An retested the system. Good to go.
Now I will make the box/holder and finish the install.



And look what followed me home ? LOL



Rides a little better at 60 psi.