M1078 LMTV CTIS Front Wheels Deflating

[InspectorBob]

Good afternoon,

First of all, I know the CTIS has been an ongoing topic on this board. Hopefully, I'm not doubling up on the same subject.

My agency purchased 7 M1078 LMTV for high water operations. Today, during some familiarization for the non military guys, one of the truck started deflating only the front tires. The CTIS control box was set on Hwy, the Hwy light kept blinking, and all air pressure gauges were above 120 psi as expected. I attempted to turn off the truck, unplug the control box, restart the vehicle, turn it off and re-plug the control box. No change. I also notice that the CTIS Manifold keeps cycling and a high pitch noise resonates from the back of the truck.

I checked the input hose (S) on the manifold and there is air pressure coming in, but no air coming out from the discharge (D) port.


Any suggestions?

 

[Jbulach]

Did it dump all the air out of the front tires? Where any of the tires lower in pressure than the rest?

 

[InspectorBob]

Yes it did, both equally.

 

[Suprman]

Pull out the banjo bolts see if someone put regular bolts in their place.

 

[m-35tom]

OK what was the finding?

 

[Ronmar]

Actually in my experimenting I saw this. Check the control solonoid on the PCU. Supply without Control and the pressure jumps up to around 40 then drops into the teens. This caused the fronts to deflate and the rear quick release to only partially open and squeal... The front axle loading on an empty truck might have something to do with this.