Airbag fitting help please - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67arch · 03-05-2007, 10:39 PM

Ok so I may be just wacko or something

I have firestone 3/8 port bags. I bought 3/8 valves , tee, cross, and ptc male adapters from ***************** Everything fit together except the male ptc adapters didn't fit in the bags, it is too big. Measures almost 5/8 in thread size and bag exactly 3/8. Anyway what do I need?

Rollie396 · 03-05-2007, 11:24 PM

Sounds like they sent you the wrong fittings?What does your invoice from SD say they sent you?If you're in a hurry you could run down to your local tractor trailer supply store with one your bags and get the right fittings (that's where I got all of mine).
Or,if there is enough room use the fittings you have with a male female pipe-pipe reducer.Though that's just another place for a leak to occur.

jimmydean · 03-05-2007, 11:42 PM

3/8th is 3/8. I didn't know SD even had 5/8th fittings, but I'm sure it's possible. Most of the air ride stuff I've seen is either 3/8 or 1/2. Call them up, they should make it right.

scoot · 03-05-2007, 11:44 PM

i don't think your bags are 3/8 port. with that measurement it is more likely 1/4 port. basically you need to get a 1/4 npt to 3/8 tube fitting.

Jaredm82 · 03-06-2007, 01:22 AM

Im with scoot on this one.

FLEET72 · 03-06-2007, 02:51 AM

Or you could just re-tap the bags to 3/8" and use the fittings you already have.

SlammedDime · 03-06-2007, 12:40 PM

The width of the threads does NOT equate to the size of the threads. A 1/4" NPT port will have a diameter of about 3/8". A 3/8" port will have about a 1/2" diameter, and so on and so forth.

I wouldn't tap the bags, I'd just get new fittings. Takes less time and unless you have the right drill bit and tap size, will cost you less money.

*Shane* · 03-06-2007, 01:19 PM

Slammed Dime is correct. NPT fittings are sized according to the particular PIPE SIZE they were designed to be used with ... NOT the thread size. Sounds like the ports on your bag are smaller than 3/8".

For example:

1/8"-27 NPT MALE END is going to measure approx. .363 at the first thread (small end of taper)

1/4"-18 NPT MALE END is going to measure approx. .477 at the first thread

3/8"-18 NPT MALE END is going to measure approx. .612 at the first thread

1/2"-14 NPT MALE END is going to measure approx. .758 at the first thread

Hope this helps.

67arch · 03-06-2007, 06:35 PM

Thanks alot guys. Starting to make sense now. Guess I need two 1/4npt x 3/8ptc fittings. I actually under ordered fittings by 2 so I'm golden.

03-05-2007, 10:39 PM	#1
67arch WTB:Patience and Talent Join Date: Sep 2006 Location: Oklahoma Posts: 119	Airbag fitting help please Ok so I may be just wacko or something I have firestone 3/8 port bags. I bought 3/8 valves , tee, cross, and ptc male adapters from ***************** Everything fit together except the male ptc adapters didn't fit in the bags, it is too big. Measures almost 5/8 in thread size and bag exactly 3/8. Anyway what do I need? __________________ 69 shortwide

03-05-2007, 11:24 PM	#2
Rollie396 someday it will be done! Join Date: Sep 2004 Location: Lloydminster,AB. Canada Posts: 1,620	Re: Airbag fitting help please Sounds like they sent you the wrong fittings?What does your invoice from SD say they sent you?If you're in a hurry you could run down to your local tractor trailer supply store with one your bags and get the right fittings (that's where I got all of mine). Or,if there is enough room use the fittings you have with a male female pipe-pipe reducer.Though that's just another place for a leak to occur. __________________ '72 C-10 Proud owner of a million new and used pieces that used to be and will once again be(god willing) a testament to the term "they don't build em like that anymore. '80 LWB 2wd beater '67 GMC long fleet (cab donor) '66 long step (parked till it's turn comes around) '65 short step (parts truck that will donate it's bed and possibly frame to the '66) '06 Grand Prix wife's car (she hardly lets me touch it) my pics

03-05-2007, 11:42 PM	#3
jimmydean Registered User Join Date: May 2005 Location: Beaverton, OR Posts: 3,728	Re: Airbag fitting help please 3/8th is 3/8. I didn't know SD even had 5/8th fittings, but I'm sure it's possible. Most of the air ride stuff I've seen is either 3/8 or 1/2. Call them up, they should make it right. __________________ New Project: 1966 LWB C20 Plans: 1/2 ton conversion Dropmember front Dropmember rear Corvette discs Restored raised bed http://67-72chevytrucks.com/vboard/s....php?p=4295210

03-05-2007, 11:44 PM	#4
scoot Registered User Join Date: Jan 2007 Location: sjc Posts: 24	Re: Airbag fitting help please i don't think your bags are 3/8 port. with that measurement it is more likely 1/4 port. basically you need to get a 1/4 npt to 3/8 tube fitting. Last edited by scoot; 03-06-2007 at 10:48 PM.

03-06-2007, 01:22 AM	#5
Jaredm82 Active Member Join Date: Jul 2005 Location: Ca Posts: 211	Re: Airbag fitting help please Im with scoot on this one.

03-06-2007, 02:51 AM	#6
FLEET72 Registered User Join Date: Jan 2007 Location: Sonoma, CA Posts: 521	Re: Airbag fitting help please Or you could just re-tap the bags to 3/8" and use the fittings you already have. __________________ Oscar '72 Shortbed Fleetside '95 Jimmy 4X4 '69 GMC Custom Camper Last edited by FLEET72; 03-06-2007 at 02:52 AM.

03-06-2007, 12:40 PM	#7
SlammedDime Registered User Join Date: Oct 2006 Location: Glendale, AZ Posts: 41	Re: Airbag fitting help please The width of the threads does NOT equate to the size of the threads. A 1/4" NPT port will have a diameter of about 3/8". A 3/8" port will have about a 1/2" diameter, and so on and so forth. I wouldn't tap the bags, I'd just get new fittings. Takes less time and unless you have the right drill bit and tap size, will cost you less money. __________________ Matt Admin @ AirRideTalk.com Win FREE Viair compressors!

03-06-2007, 01:19 PM	#8
Shane Account Suspended Join Date: Jun 2000 Location: over yonder Posts: 14,270	Re: Airbag fitting help please Slammed Dime is correct. NPT fittings are sized according to the particular PIPE SIZE they were designed to be used with ... NOT the thread size. Sounds like the ports on your bag are smaller than 3/8". For example: 1/8"-27 NPT MALE END is going to measure approx. .363 at the first thread (small end of taper) 1/4"-18 NPT MALE END is going to measure approx. .477 at the first thread 3/8"-18 NPT MALE END is going to measure approx. .612 at the first thread 1/2"-14 NPT MALE END is going to measure approx. .758 at the first thread Hope this helps.

03-06-2007, 06:35 PM	#9
67arch WTB:Patience and Talent Join Date: Sep 2006 Location: Oklahoma Posts: 119	Re: Airbag fitting help please Thanks alot guys. Starting to make sense now. Guess I need two 1/4npt x 3/8ptc fittings. I actually under ordered fittings by 2 so I'm golden. __________________ 69 shortwide



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