M35A3 :: to CTIS or not to CTIS...

[Sgt Jiggins]

Howdy Folks,

Recently purchased an M35A3 - my first A3, but not my first M35. I know some of what to look for with this truck, but some of it... right now, I need to swap out the dry rotted tires. I found the stickied PDF in the TMs section discussing how to swap out tires/work on the wheel-related bits of the CTIS.

Which leaves me wondering several things:

1)should I even try to resurrect the CTIS?
2)are those little brass washers securing the CTIS valve inside the tire in any way special or is this something I can get at the hardware store?
3)I found the orings for $10/ea on ebay. Anybody know of better options/pricing?
4)are runflats worthwhile?

5)anything else I'm missing when I'm in there anyway?

Thank you,
SJ

 

[Redneck of Enon]

on my A3 the CTIS didn't work when I got it so I went to the local hardware and made it where each tire has a valve stem ...some don't like this idea but I'm happy with it . and my tires have some dry rot so I try to keep armor all on them and so far I have not noticed any further cracking

 

[rtk]

Same with me , system never worked and quad rings were leaking , so I just converted it over to A2 style bearing and seals . Run flats are a whole different story , do a search on that issue on this site , well worth the read . If you do keep the system I do have a few parts leftover . Also check your air compressor for the pressure relief valve update on your air line , I also think I have some of those in the storage trailer

 

[glcaines]

The CTIS worked great on my A3 when I first recovered it from Fort McCoy years ago although the tires would lose pressure over a few weeks. It has worked great ever since although I did replace the air dryer and the valve stem grommets. You do not want to use hardware nuts on the valve stems. The valve stems is what causes most problems with the CTIS and tires going flat. I bought new nuts and grommets from Eriks. The old ones leaked. When you replace the grommets and tighten the nuts, you need to tighten the nuts to 45 - 60 ft lb. Since the nuts are tapered, I ground a new socket to a tapered edge so that it gripped the nut adequately. Proper torque is mandatory. Also, do not use any sealant on the grommets or the large O-rings. Also, never re-use an o-ring. I haven't added any air to any of my A3 tires in over a year and they are still fully inflated. I seldom use the CTIS, although it is fully functional, because I normally run 60 psi in the tires to increase life and improve handling. Please note that the wheels are redlined at 60 psi. The CTIS won't inflate over 45 psi. The CTIS system is very simple and very easy to work on. I dismantled a spare CTIS wheel valve someone gave me and there was nothing to it. Very easy to open and clean if needed. I would recommend leaving the CTIS in place, repairing it if needed. I'm also still running the same original tires on the A3 with one exception. I still have about 75% of the tread left even after a lot of mileage. Running 60 psi really helps with the tread life.

 

[Karl kostman]

A good friend of mine who was a mechanic in a guard unit were talking once and I think I was licking up some parts from him while he was at the unit working his weekend and I was in the market for a 939 series 5 ton and I asked him about the CTIS trucks and he took me out behind the building to the holding yard where truck park prior to being serviced and he said just look out there at all those trucks there was maybe 22 trucks out there and on one side just about every truck had at least 2 or 3 flat tires on it, he then asked me what do I think that every truck with flat tires had in common? I didnt know, then he told they all have CTIS systems on them! Very heavy maintenance, very expensive maintenance and it usually needs a lot of both! He then said if you get a truck with CTIS the first thing he would do is disable it!
Karl

 

[Sgt Jiggins]

This thread is a classic example of why I love this site so much: people will share good, bad, and ugly without regard for popular or conventional wisdom. Thanks to all. Not sure I have any better idea yet what I'm going to do, but all the input has been thought provoking.

 

[frank8003]

Get the six guys from the motor pool to fix it.
They have the parts to make it work and they can't go back to barrack until it works.

 

[Sgt Jiggins]

Get the six guys from the motor pool to fix it.

YEA!!! Where are those guys?!!