CTIS that worked great, but now...

[crolfe1984]

So about two weeks ago I acquired my very first Steel Solider: a 1990 BMY M923A2 with roughly 17k miles and about 700 hours on it. Now the good news is that I went private party and the truck seemed well cared for. Recent oil and trans fluid changes, new filters, fresh tires with only a couple hundred miles on them, great paint, nice truck overall.

The other great thing is that EVERYTHING WORKED. The wipers, all the guages, dash lights, I mean everything was good to go. The ABS light stayed on, but that should be an easy fix. The CTIS also worked perfectly, and the 200 mile trip back home went without any issues.

Now recently the CTIS comes on, acts as normal, but after 2 long bursts of trying to fill the tires I get the 5 flashing lights. I've traced an air leak to the right middle wheel around the hub area. When starting the truck up the CTIS tries to push air to the wheel but I hear a high-pressure (rather loud) hiss from this area. Anyone recently take apart the wheel hub assemly to have a similar issue?

I'd like to get it fixed as the rest of the system has been running fine. Wondering if its just a matter of cleaning up some clogged parts or if its a bit more involved when working on the CTIS at the hub/wheel level.

 

[Suprman]

If it's a hub seal the parts are cheap the labor is not. You have to pull the axle shaft out. They all go bad eventually.

 

[crolfe1984]

I'll do the soapy water spray test tonight. I've got a feeling that the leak is from the small parts behind the protective cover and not the hub seal. I hope I'm right!

 

[Suprman]

If it's leaking behind the cover it may just be a loose connection or need a new o ring. I use the cheapie kit from harbor freight for the replacement o rings.

 

[crolfe1984]

Since the CTIS is a relatively new system to me, I'll take basic precuations like draining the air from the system prior to turning any wrenches. I'll be sure to have the TM saved as a PDF on my phone right next to me. Any other words of wisdom before I crack this thing open?

I'll update my findings later.

 

[Suprman]

The wheel valves hold air in the tires. You don't need to drain the truck air prior to working on it but you need to make sure the brake is set so the truck does not roll.

 

[1 Patriot-of-many]

Most of mine have been simply the small oring on the hose connection to the valve stem or simply a lose connection on the other side of the hose. Easy fixes.

 

[1 Patriot-of-many]

I'll do the soapy water spray test tonight. I've got a feeling that the leak is from the small parts behind the protective cover and not the hub seal. I hope I'm right!

Usually is just the connection being loose.

 

[crolfe1984]

So I had to wait on the soap-spray test as temps dipped to 28 degrees F last night, but I did notice that the valve unit has come completely loose from the protective cover. It was only held onto the wheel by the hoses. It appears there are two bolts/nuts that have come loose which permitted the valve unit to slip free from the cover.

That certainly can't be good for a secure connection when its lolling about at 55 MPH. Time to take off the cover, check the unit for leaks, re-tighten, and then check the other five wheels.

 

[crolfe1984]

Problem fixed! After I got the protective cover off it was readily apparent that that large fitting (1.25" nut) and the rubber seal was loose. A few turns of the wrench and all went back to normal.

 

[MtnSnow]

Congrats on a easy fix!

 

[CUCVLOVER]

Is the CTIS still working?

 

[crolfe1984]

Is the CTIS still working?

Indeed it is! Other than that one hiccup the CTIS has worked perfectly since it came out of service some 3-or-so years ago.

 

[CUCVLOVER]

So o guess the ctis is reliable?

 

[Rmtaunton]

I guess it just depends on truck and how much work you want to out in it , some have few problems or none and some believe to cap it off right away.

But don't ask me you guys keep out bidding me ha.

 

[CUCVLOVER]

What things should one check out on the ctis when buying a truck?

Note I'm not trying to hijack the thread just figured the couple of questions could be answered here.

 

[Rmtaunton]

Lost last two by a hundred bucks and next year when I see him at GA ralley I am gonna tackle him and throw my t- shirt on him from last years rally and I haven't washed it ha

 

[CUCVLOVER]

Lost last two by a hundred bucks and next year when I see him at GA ralley I am gonna tackle him and throw my t- shirt on him from last years rally and I haven't washed it ha

OK??
Who are you tackling? Just curious.
Sorry I'm getting off track.

 

[Rmtaunton]

It's all in fun ! But no I'm not telling

 

[crolfe1984]

Exactly what Rmtaunton said. As for myself and a few other members here the CTIS has proved itself reliable (and a great feature too).

However, I think the majority of 939A2 owners will tell you that the CTIS is an over-complicated system with hard-to-find & expensive parts that eventually will need replacing. My suggestion is this... if you have it and it works, keep it. If you have multiple issues or leaks, cap it off and unhook the computer.

In my case the VERY large nut that connected the air supply from the hub came loose. This caused a 5-flash error and a rather ominous hissing sound from the right rear side. All I had to do was remove the protective cover on the wheel, grab the 15" adjustable wrench, and tighten things up a bit. I was lucky!