Disable the CTIS?

[PBR street gang]

Greetings. My LMTV has a discharging rear tire and I suspect the right rear wheel manifold valve (bubbling). Until I can get my head around the CTIS and find parts (preformed packing kits), I am consider disabling the CTIS. I am not finding any system disabling or partial disabling information in the manuals. Any information would be appreciated. Thank you in advance!

 

[porkysplace]

You might want to read the similar threads at the bottom of the page. I'm sure it will be similar to the M35a3.

 

[Suprman]

You can find resting leaks with windex. Sometimes just an o ring or something tightened up is all that's required. Disabling the ctis will only prevent automatic reinflation when you start the truck. The wheel will still leak if it leaks when sitting with the truck off now.

 

[alltheway82nd]

try un plugging the controller...it should disable the system

 

[Coffey1]

That would disable the system but not stop the leak.
Pull hose from wheel valve to tire stem and install Schrader on all 4 tires
If tire is leaking it will still leak and go down.

I would just find the leak and fix.
If you got a shop compressed just air truck with glad hand and start spraying winded or leak detect and keep looking some leaks take a while to show be patient and you will find them.

 

[Suprman]

Dosnt work like that on an lmtv. Most wheels you can't just screw in a schrader valve.

 

[Coffey1]

Well crappie then I guess you just need to find the leaks.
Supra is there a way to isolate the tire to see if tire or tires are leaking.

 

[Suprman]

Yes. Take the feed line off. Not the one from the valve to the stem. Scrunch a plastic bag around the line use a rubber band to hold it on let it sit for a while. Leaky valve will inflate the bag. Use windex around the 2 piece rim look for bubbles those will be air leaks.

 

[Hwhomes]

Is there a diagram available the lists the various parts and their names? Hard to follow the advice when you don't know what parts being talked about.

 

[Coffey1]

Take the air line off that's feeding air to axel put bag on it if anything is leaking it will inflat the bag.
I think that's what he is telling us
Correct me if me supra if I am wrong.

 

[Suprman]

In the parts tm

 

[Suprman]

The line that comes out of the rim on a banjo bolt going to the ctis valve. If air is leaking back out thru the valve then that's where it will come out. If the lines from the stem to valve are leaky windex should find that. The wheel valves are probably a scheduled replacement item. Moisture corrodes them inside and then the flapper cannot seal properly and air will start seeping by.

 

[Coffey1]

Thank you sir

 

[KRedd]

View attachment 545-3 CTIS Wheel valve filter.pdf

 

[coachgeo]

... The wheel valves are probably a scheduled replacement item. Moisture corrodes them inside and then the flapper cannot seal properly and air will start seeping by.

Have seen you say this in several threads. Your most likely right. Have you seen any hints to this in any of the manuals? Have you got any ideas on how to help those pesky flaps last longer? Spray lube, WD40 orrr? into the system as a routine maintenance?

 

[Suprman]

The ctis is basically the same system as the m939a2 trucks have. The flappers are
rubber and they age and dont seal well, moisture will
corrode the valves metal body over time and the flap cant get a good seal. Chemicals sprayed in will cause damage. Best way to help the ctis stay working is have a good working air dryer.

 

[coachgeo]

The ctis is basically the same system as the m939a2 trucks have. The flappers are rubber and they age and dont seal well, moisture will corrode the valves metal body over time and the flap cant get a good seal. Chemicals sprayed in will cause damage. Best way to help the ctis stay working is have a good working air dryer.

noted and thanks

 

[Suprman]

 

[coachgeo]

View attachment 614632View attachment 614633

Which part in the pics ends up with pits that cause sealing issues? before reassembly when putting in new rubber valve wondering if a coat of epoxy/JB weld to fill the pits..... allowed to dry and fully cure, then sanded and polished flat, would be wise. Maybe along with a coating of something to help prevent more pits would be in order. Not sure what that something would be though.

 

[Suprman]

Around the center metal nut piece with a hole. I have seen these with the metal housing significantly corroded though. The rubber flaps seem to go bad with age. There is a rebuild kit available though. I think it has a new flapper, spring, center metal piece and 4 new bolts to hold the valve together.