Axle housing breather fitting question
02-29-2012, 04:58 PM
#1
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Thread Starter
Axle housing breather fitting question
What is the thread size/pitch of the fitting at the top of our rear axle housing? Is it pipe thread?
Andreas
Andreas
03-01-2012, 07:29 AM
#3
Hypothesis:
The breather has tapered threads(so do all the intake manifold parts with threads that are compatible). This is easily detectable through visual observation(plain to see with the naked eye). So the odds of it not being ⅛"-27 NPT, or ⅛"-28 BSPT(JIS B 0203-2), are practically non-existent. And since M10-1.0 threads are not tapered, they are obviously not correct.
Experiment:
I have my spare breather in my hands right now. It threads perfectly into a pipe fitting I just found with ⅛"-27 NPT threads. An M10-1.0 bolt in the same fitting will only turn ~3½ threads into it before seizing. However, the same M10-1.0 bolt will only turn ~1 thread into the breather hole in my spare axle housing before seizing. But, the breather's fit is also slightly tighter in the axle housing than in the pipe fitting. Yet it threads into the exact same spot before becoming snug in either one(~7½ threads).
Conclusion:
⅛"-27 NPT is either the correct size, or atleast much closer to it than M10-1.0. Though the correct size much more likely to be JIS B 0203-2(⅛"-28 BSPT) in reality.
http://www.jgbhose.com/base_pages/co...se.asp#tapered
The breather has tapered threads(so do all the intake manifold parts with threads that are compatible). This is easily detectable through visual observation(plain to see with the naked eye). So the odds of it not being ⅛"-27 NPT, or ⅛"-28 BSPT(JIS B 0203-2), are practically non-existent. And since M10-1.0 threads are not tapered, they are obviously not correct.
Experiment:
I have my spare breather in my hands right now. It threads perfectly into a pipe fitting I just found with ⅛"-27 NPT threads. An M10-1.0 bolt in the same fitting will only turn ~3½ threads into it before seizing. However, the same M10-1.0 bolt will only turn ~1 thread into the breather hole in my spare axle housing before seizing. But, the breather's fit is also slightly tighter in the axle housing than in the pipe fitting. Yet it threads into the exact same spot before becoming snug in either one(~7½ threads).
Conclusion:
⅛"-27 NPT is either the correct size, or atleast much closer to it than M10-1.0. Though the correct size much more likely to be JIS B 0203-2(⅛"-28 BSPT) in reality.
Japanese Tapered Pipe Thread
The Japanese tapered pipe thread connector is identical to and fully interchangeable with the BSPT (tapered) connector. The Japanese connector does not have a 30° Flare, and will not mate with the BSPP female.
The threads conform to JIS B 0203, which are the same as BSPT threads.
The seal on the Japanese tapered pipe thread connector is made on the threads.
The Japanese tapered pipe thread connector is identical to and fully interchangeable with the BSPT (tapered) connector. The Japanese connector does not have a 30° Flare, and will not mate with the BSPP female.
The threads conform to JIS B 0203, which are the same as BSPT threads.
The seal on the Japanese tapered pipe thread connector is made on the threads.
Last edited by MudHippy; 03-01-2012 at 10:16 AM.
03-01-2012, 03:00 PM
#5
Contributing Member
Thread Starter
Hypothesis:
The breather has tapered threads(so do all the intake manifold parts with threads that are compatible). This is easily detectable through visual observation(plain to see with the naked eye). So the odds of it not being ⅛"-27 NPT, or ⅛"-28 BSPT(JIS B 0203-2), are practically non-existent. And since M10-1.0 threads are not tapered, they are obviously not correct.
Experiment:
I have my spare breather in my hands right now. It threads perfectly into a pipe fitting I just found with ⅛"-27 NPT threads. An M10-1.0 bolt in the same fitting will only turn ~3½ threads into it before seizing. However, the same M10-1.0 bolt will only turn ~1 thread into the breather hole in my spare axle housing before seizing. But, the breather's fit is also slightly tighter in the axle housing than in the pipe fitting. Yet it threads into the exact same spot before becoming snug in either one(~7½ threads).
Conclusion:
⅛"-27 NPT is either the correct size, or atleast much closer to it than M10-1.0. Though the correct size much more likely to be JIS B 0203-2(⅛"-28 BSPT) in reality.
http://www.jgbhose.com/base_pages/co...se.asp#tapered
The breather has tapered threads(so do all the intake manifold parts with threads that are compatible). This is easily detectable through visual observation(plain to see with the naked eye). So the odds of it not being ⅛"-27 NPT, or ⅛"-28 BSPT(JIS B 0203-2), are practically non-existent. And since M10-1.0 threads are not tapered, they are obviously not correct.
Experiment:
I have my spare breather in my hands right now. It threads perfectly into a pipe fitting I just found with ⅛"-27 NPT threads. An M10-1.0 bolt in the same fitting will only turn ~3½ threads into it before seizing. However, the same M10-1.0 bolt will only turn ~1 thread into the breather hole in my spare axle housing before seizing. But, the breather's fit is also slightly tighter in the axle housing than in the pipe fitting. Yet it threads into the exact same spot before becoming snug in either one(~7½ threads).
Conclusion:
⅛"-27 NPT is either the correct size, or atleast much closer to it than M10-1.0. Though the correct size much more likely to be JIS B 0203-2(⅛"-28 BSPT) in reality.
http://www.jgbhose.com/base_pages/co...se.asp#tapered
So I take it the threads are 1/8"-27 NPT?
Thank you!
Andreas
03-01-2012, 04:00 PM
#6
I can't prove they ain't. Since I have no other examples that can say with 100% certainty are JIS B 0203-2(⅛"-28 BSPT) to compare them to.
But like I said, my money is on Japanese Tapered Pipe Thread Dash Size -2 , a.k.a. JIS B 0203-2(equivalent to ⅛"-28 BSPT).
However, if I were to substitute a non-OEM (male)fitting for use with said (female)threads(assumed to be JIS B 0203-2/⅛"-28 BSPT), I'm comfortable using one with ⅛"-27 NPT threads. Close enough for me and the girls I go with(no pun intended).
But like I said, my money is on Japanese Tapered Pipe Thread Dash Size -2 , a.k.a. JIS B 0203-2(equivalent to ⅛"-28 BSPT).
However, if I were to substitute a non-OEM (male)fitting for use with said (female)threads(assumed to be JIS B 0203-2/⅛"-28 BSPT), I'm comfortable using one with ⅛"-27 NPT threads. Close enough for me and the girls I go with(no pun intended).
Last edited by MudHippy; 03-01-2012 at 04:09 PM.
03-01-2012, 04:04 PM
#7
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