Airpak rebuild

Hi all. I'm rebuilding my airpack and noticed teflon tape on the threads of all the non-compression fittings. Is that the best idea or should I use a liquid thread sealant?

I prefer Teflon tape. Mechanics I work with in a chemical plant use Teflon tape with rectorseal yellow pipe sealant on top of the Teflon. That may be a bit of an overkill for you on your truck & it is very messy!

If I remember right most of those fittings seal with a copper crush-washer so you shouldn't put anything on the threads. They're not the sealing surface. Just get a new washer, clean the threads, and it should seal. If there are NPT threads then I like some teflon tape and some paste smeared over it. Seems to always seal first try that way. When I try just the tape or just the paste I have issues.

I like Permatex#1 for thread sealing.

https://www.permatex.com/products/gasketing/gasket-sealants/permatex-form-a-gasket-no-1-sealant/

For most fittings I use laco slic-tite in the old metal cans (mainly because I got a dozen quart cans from work 20 years ago I'm almost through the first quart!)
For the air fittings you could use teflon tape, but I fine for liquid lines or high pressure fittings I would use a pipe sealant we use the slic-tite on our waterjet pump rebuilds and that goes to 60,000psi

Seems most of us have, through example, been led to believe that common white teflon tape is THE standard most often when it comes to sealing threads. But, if you do a little digging, you'll find out that the main purpose for said tape is actually NOT to seal, but merely to make the threads slippery, allowing connections to be tightened to a more intimate relationship, and also to make the components easier to take apart down the road. True, teflon tape does help seal by basically clogging the spaces in between the threads, but the paste-type products are what is specifically designed and intended to actually form a proper seal between threads, and they also provide the lubricity desired to help keep parts from galling and stripping when snugged-up. You just have to make sure that you're only applying it to the male portion of the threads, and that the goo you're using is compatible with what's being pumped through the parts

I ordered and received my rebuild kit. I am starting to disassemble now. So far I see nothing out of the ordinary. What normally goes wrong with these airpaks? A particular oring? All I know is brake fluid is blasting out the firewall vent line and the PS article said it was a symptom of airpak issue.

Dot 5 eats "Teflon tape" , Should I type that again?
Teflon tape is a lubricant
You know, ..............pipe threads, fittings, what have you, at 3/4" per foot taper,
It is meant for PIPE

How about PIPE type threads only 3/4 inches long?

Teflon is a lubricant.
Teflon tape is necessary on fittings like Swagelok stainless steel fittings because
THAT metal DOES NOT squash like ferrous fittings................
Teflon tape comes in many flavors. Some tape from Swagelok is good, others too.
What does the TM say to use?

There is many threads on what is the best stuff to use.
Look up what was used by the OEM on the bottom of your fuel booster pump. That stuff will not EVER leak. I can not say one would ever to be able to get it off again but it will never leak.
Same stuff used on pipe to lube and seal threads by 1954 plumbers.
Like in my kitchen drains.

Look it up.

frank8003 said:

Dot 5 eats "Teflon tape" , Should I type that again?
Teflon tape is a lubricant
You know, ..............pipe threads, fittings, what have you, at 3/4" per foot taper,
It is meant for PIPE

How about PIPE type threads only 3/4 inches long?

Teflon is a lubricant.
Teflon tape is necessary on fittings like Swagelok stainless steel fittings because
THAT metal DOES NOT squash like ferrous fittings................
Teflon tape comes in many flavors. Some tape from Swagelok is good, others too.
What does the TM say to use?

There is many threads on what is the best stuff to use.
Look up what was used by the OEM on the bottom of your fuel booster pump. That stuff will not EVER leak. I can not say one would ever to be able to get it off again but it will never leak.
Same stuff used on pipe to lube and seal threads by 1954 plumbers.
Like in my kitchen drains.

Look it up.

Click to expand...

Why not tell us instead of the look it up?

I am just about done with the rebuild but nobody seems to know anything about the oring between the two big piston halves. It looks beveled. The kit did not come with it either.

Kharville said:

I am just about done with the rebuild but nobody seems to know anything about the oring between the two big piston halves. It looks beveled. The kit did not come with it either.

Click to expand...

It is item 16, the oring between the halves.