M923A2: What is this thing?

[Andyrv6av8r]

It lives right under the dash on the passenger side. Is this some sort of filter/water trap? It has 1/8 NPT male threads on the bottom with a hole in it. And it's leaking a noticeable amount of air on my truck. Not enough to affect pressure when running, but I hear it easily after shutdown and it drains the tanks. Easy finger pressure blocks it off. I plan on putting a cap on it to seal it up.

 

[wheelspinner]

Water filter for the CTIS. It should have an "O" ring that just needs a little love.

 

[Suprman]

Sometimes you can take out the little piece inside with the o-ring and screw a schrader valve in.

 

[hklvette]

Or if you have the air drier functioning properly, you can remove it completely.

 

[Suprman]

Bad idea even with the air dryer some moisture and dirt particles make their way into the air system. The ctis valve body is sensitive it needs the extra catch trap.

 

[todds112]

I took mine apart and cleaned it today. It was sticking open too. There were a few chunks of crud in it that I assume were preventing it from closing.

The plunger (circled in red) has a tiny stem on the bottom. It's only about 1mm thick. The stem drops down into the little O-Ring in the bottom of the canister. Putting it back together and getting that little stem back in the right position without breaking it off is tricky. I found the best way was to pop out the little O-ring. Put the O-ring on the stem of that plunger, then put them in together as an assembly. You'll need a pair of tweezers or small needle nose pliers to get it down in there. On mine part #21, the filter, was a little different than pictured. It and the piece below it were 1 part. It just screwed up into the cap.

 

[Andyrv6av8r]

Or if you have the air drier functioning properly, you can remove it completely.

I just changed out my air dryer with a brand new one from Suprman but I plan to take that assembly apart tomorrow just in case a piece of crud is in there. Thanks everyone for your help.

 

[hklvette]

Bad idea even with the air dryer some moisture and dirt particles make their way into the air system. The ctis valve body is sensitive it needs the extra catch trap.

Hmm hadn't thought of that, and I think you're right. I'll have to put one back in...

 

[Andyrv6av8r]

Well I took it apart a couple of days ago, cleaned it and lubed the o-ring. All looked good until this evening when it commenced to start leaking again. Does anyone know what size and where to get that sub miniature, tiny o-ring without it costing me $10 for shipping? I'm ready to screw a 10-32 screw in the bottom to seal it up ( which it's threaded for already ).

 

[Suprman]

A regular tire stem schrader valve works nicely

 

[Andyrv6av8r]

A regular tire stem schrader valve works nicely

I love this site! And your air dryers!

 

[ghettoct]

i cleaned and lubed the o rings and it still leaked, found on this site someone who posted where to find replacement. its from MSC industrial supply mableton ga. catalog item number was 01780204. 1/4 inch metal auto mini air filter (manufactured by norgren, #f02-200-a1ma) was$ 46.08 and got free next day delivery. its the same exact part as what i had. fixed my leak so i was happy. (also be aware if you do replace that there is an arrow for direction of flow of air on body).

 

[Andyrv6av8r]

I took mine apart and cleaned it today. It was sticking open too. There were a few chunks of crud in it that I assume were preventing it from closing.

The plunger (circled in red) has a tiny stem on the bottom. It's only about 1mm thick. The stem drops down into the little O-Ring in the bottom of the canister. Putting it back together and getting that little stem back in the right position without breaking it off is tricky. I found the best way was to pop out the little O-ring. Put the O-ring on the stem of that plunger, then put them in together as an assembly. You'll need a pair of tweezers or small needle nose pliers to get it down in there. On mine part #21, the filter, was a little different than pictured. It and the piece below it were 1 part. It just screwed up into the cap.

View attachment 538876

Anyone know what page that is in the TM's? I'm trying to find the O-ring part #.

 

[todds112]

That's from the parts manual. 620-1. Part# 5938-01. Doesn't show a NSN for it as it's part of a "kit" PN 3652-11.

 

[turnkey]

Great info...Got my replacement O-ring at ACE hardware...Went into their O-ring replacement parts kit in the water stuff alise....3.40 for the part...

 

[Andyrv6av8r]

Well I made an interesting discovery this evening. While looking at the white plunger thingy I decided to flip the upper rubber cupped gasket over so that it pointed up instead of down. It seemed to me like it would seal much better. And it worked! Not even a hint of a leak so far. Maybe it was installed upside down from the beginning? It wasn't the O-ring leaking after all it seems. Can someone smarter than me explain just how this thing is supposed to operate? Is it supposed to fill with water on the bottom side of the upper cupped gasket, " push " it up and dump the water out of the bottom when the tip " unseats " off of the O-ring?

 

[todds112]

Mine stuck open again today. I pulled the plunger and the little o-ring out and installed a shrader valve.

 

[Alexsha]

Mine stuck open again today. I pulled the plunger and the little o-ring out and installed a shrader valve.

I don't have one of these plungers. Could you take a photo of the original plunger as well as a photo of your Schrader valve fix and post them?

 

[todds112]

Here is the Parts diagram:

This is the plunger (circled in red above):


Here is the type of filter I have in mine (Norgren 3652-11):



Notice it's different from the one shown in the parts diagram. Maybe it's a newer style. But what I see happening is the plunger moves up and the little stem comes out of the O-ring. The plunger then "tilts" and won't go back down into the O-ring to seal. Maybe the newer filter allows the plunger to move up too far?

I removed the plunger and the little O-ring from the canister. You need to push up inside from the threaded nipple on the bottom of the canister to pop out the o-ring. Then just screw in a tire Schrader valve (up from the bottom) inside the threaded nipple. I had to remove the o-ring because the Schrader valve got stuck on it in the open position. Insert Schrader valve in here:



I figure the filter will still "filter" the air and I will just open the valve when the system is pressurized and let some air out (like airing down a tire) and it should blow out any contamination in the bowl.

 

[Alexsha]

I think mine had the same issue but instead of adding a valve, the someone just put a screw in to plug it. Fun fun.