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Vent line brass T on firewall M38
Posted: Sat Sep 30, 2006 6:45 pm
by Ryan_Miller
I have been working on my fuel, vent lines for the M38.
On the firewall brass T, in the ORD 9 Tee, flared tube, inverted, striaght, brass, 3/16 inch (w/o nuts). 178654 H006-0381110
I know that 3 vent lines screw into this T, but is the T female flared on all three sides or flared on 2 sides with pipe threads on the third side as some of the other 1/4 inch fuel and vent line brass T.
Posted: Sun Oct 01, 2006 7:06 am
by OKCM38CDN
Ryan,
Which "T" are you talking about??? I know of one on the air filter, one for the wipers at the manifold... can't think of another at this time...
The one for the air filter should have a 1/8" pipe fitting male on one end and the other two 3/16" inverted flares; the one for the manifold has 1/4" inverted flares on each end and a 1/8" female pipe fitting on the "Tee" for the special 0.040" fitting...
Will look in the SNL to find the one you are talking about...
Per my SNL that "Tee" is (superseded by ELBOW 325200)...
I would go with the elbow, unless you are doing a factory restoration...
Hope this helps...
Posted: Sun Oct 01, 2006 2:17 pm
by Ryan_Miller
Hal,
There are 4 brass T for the vent system:
1. Air cleaner (two female ends and one male end)
2. Intake manifold (two female and one male end)
3. Windshield wiper line under hood off the vacuum pump near the intake manifold T (2 female flared and 1 female pipe)
4. Firewall - the master brake cylinder, transmission vent to the this T and then a line runs from this T to the air cleaner T.
Re: Vent line brass T on firewall M38
Posted: Sun Oct 01, 2006 8:06 pm
by BobW
Ryan_Miller wrote:I have been working on my fuel, vent lines for the M38.
On the firewall brass T, in the ORD 9 Tee, flared tube, inverted, striaght, brass, 3/16 inch (w/o nuts). 178654 H006-0381110
I know that 3 vent lines screw into this T, but is the T female flared on all three sides or flared on 2 sides with pipe threads on the third side as some of the other 1/4 inch fuel and vent line brass T.
All three are female inverted flare for 3/16" tube like Weatherhead #702x3.
Posted: Mon Oct 02, 2006 7:10 am
by Ryan_Miller
Thanks Bob!
I was going to Fastenal today to check thier weatherhead catalog. I had looked it up earlier on the internet catalog, but could not find it.
With that part number I found it on the e-catalog:
3/16"Tube 1.09" OAL,2000psi Brass Inverted Flare,Union Tee
$1.98
Availability: In-Stock Item
Package Quantity: 1 (EA)
http://www.fastenal.com/web/products/de ... 274-131280
Posted: Mon Oct 02, 2006 7:17 am
by wesk
Ryan & Bob W,
Since that "T" gets superseded by the 325200 elbow in the late ORD 9 do you guys know which line was relocated or deleted and when that happened?
Posted: Mon Oct 02, 2006 8:37 am
by OKCM38CDN
Wes,
I think they separated te master brake line and transmission lines. The transmission can get its venting from the bell housing / transfer case line and the master cylinder now goes direct to the air filter...
That is the way my lines are run...
Hope this helps...
Posted: Mon Oct 02, 2006 1:45 pm
by Ryan_Miller
Wes,
The vent lines changed at engine serial number MC74419 listed in the ORD 9 1955 along with clips etc. Check pages 73, 77, 55, 53, etc These pages list the engine serial number.
If you turn to page 76 ORD 9 1955 it lists a clip that was added for the bell housing pressure tube to oil pressure sending unit after vehicle serial number MC53261. WO-807467
Fuel tank goes directly to the air cleaner, master cylinder goes to the air cleaner brass T. Transmission is vented through the same line as the bess housing and ends up on the vaccum pump middle outlet.
I have been trying to locate a couple of brass elbows (double flare female ends in 3/16).
Anyone have a source?
Posted: Mon Oct 02, 2006 5:00 pm
by OKCM38CDN
GOOD LUCK, on the elbows... I have tried several sources, these have been discontinued... However for the proper amount of cash to set up the machines and the proper order numbers we will make them for you...
It works out to be $50-$100 set up fee and minimum of 1000 units...
I got the same story for the Wiper "Tee"...
I went with the 3/16" inverted flare to 1/8" female pipe elbows and had to add the 1/8" male pipe to 3/16" adapter ...
Hope this helps...
Posted: Mon Oct 02, 2006 6:01 pm
by BobW
The dash Tees went away as the venting system was updated.
The first system on the V-35 had 2 dash Tees (see drawing below)
Then the M-38 separated the fuel vent from the master cylinder like this. (see drawing below)
Finally the late M-38 had a pressurized bellhousing/gear box and the other dash Tee was replaced with an elbow. (see drawing below)

Posted: Mon Oct 02, 2006 8:54 pm
by Cacti_Ken
Referring to the last picture, I don't see a purpose for the two 90 deg. elbow fittings in the master cylinder vent line to air breather.
Posted: Tue Oct 03, 2006 4:37 am
by BobW
I think the reason for the elbows was just so the existing lines did not have to be changed. When the Tee(s) were eliminated due to plumbing changes they were just replaced with elbows. That way existing lines could still be used.
Posted: Tue Oct 03, 2006 11:23 am
by Cacti_Ken
I see your point Bob. I was having to do all the tubing since none of it was there, and didnt' see the need for the two 90's.
Ken
Posted: Tue Oct 03, 2006 11:27 am
by wesk
Bob,
I believe the six pilot model M38's had two firewall "T"s also (this would explain why we have two in the ORD 9's). I believe a production factory M38 thru MC53262 should have an elbow on the left and a "T" on the right for the master cylinder line. Then after MC53262 they should have two elbows.
Posted: Tue Oct 03, 2006 6:17 pm
by BobW
wesk wrote:I believe the six pilot model M38's had two firewall "T"s also (this would explain why we have two in the ORD 9's). .
I forgot about the pilot models. From the service info it does seem like they had the 2 firewall Tees. They also seem to have had an axle venting system that wasn't on any of the other Jeeps.
wesk wrote:I believe a production factory M38 thru MC53262 should have an elbow on the left and a "T" on the right for the master cylinder line. .
That's my center drawing. It is labeled with the engine number of the change, not the vehicle number.
wesk wrote:Then after MC53262 they should have two elbows.
That is the bottom drawing.