RexSeven
RexSeven SuperDork
8/11/11 6:13 p.m.

Can Loctite Blue and/or Red be used as an airtight thread sealant? Not just as a thread locker- I have something I'm working on that needs to be airtight and Teflon tape won't work.

benzbaron
benzbaron Dork
8/11/11 7:20 p.m.

I think I've seen RTV used on threads or use teflon pipe dope, I don't like the idea of removing something with copious amounts of lock tite on it. Figure if pipe dope is good enough to seal high pressure gases it would probably work for your application.

Taiden
Taiden HalfDork
8/11/11 7:33 p.m.

I like to use RTV black when on the threads I replace a PCV. Not that it means anything for you.

fasted58
fasted58 Dork
8/11/11 8:13 p.m.

Thread seal tape and pipe dope are not a thread sealant per se, they are a merely lubricant designed to aid in deforming the male to female threads which do make the seal.

Red or blue loctite should serve the same purpose as it seems viscous enough and it could help a fitting from loosening due to vibration. I've used anti-sieze on steel to aluminum also, like an intake. We used a loctite industrial pipe dope on vibrating equipment that dried like an epoxy, damn that was good stuff but I haven't seen it in years. JB Weld might be worth a try if the threads are shot and all else fails, just leave the first thread or two bare.

Toyman01
Toyman01 GRM+ Memberand SuperDork
8/11/11 8:27 p.m.

Form-A-Gasket is what I use. You might want to get it apart someday.

RexSeven
RexSeven SuperDork
8/11/11 8:57 p.m.

It's an A/C fitting (R12 to R134a). I don't know if I will be removing it any time soon.

chandlerGTi
chandlerGTi Reader
8/11/11 9:11 p.m.

Why don't you find loctite brand thread sealant? You can usually find it at plumbing stores.

motomoron
motomoron HalfDork
8/11/11 10:04 p.m.

A/C fittings are flares generally as far as I'm aware. The threads should be clamping force only, not pressure retention. See hotlinked pics...

RexSeven
RexSeven SuperDork
8/11/11 10:08 p.m.

The R134a conversion fitting screws onto the old R12 stem sticking out from the low pressure side of the refrigerant line. It was an Autozone kit and the new R134a fitting had some threadlocker already on it. Unfortunately, it wasn't enough to prevent a leak even after I cleaned the old gunk out of the stem's screw threads.

Note: The A/C system was emptied of R12 by an A/C shop before I began work.

44Dwarf
44Dwarf Dork
8/12/11 5:54 a.m.

Red can be but Green (bearing and sleeve retainer) is best for pressure sealing. add 1 drop screw in remove and add second drop screw in and tighten.
Loctite is spec-ed for use on many aftermarket brake master cylinders.

44

KATYB
KATYB HalfDork
8/12/11 6:25 a.m.

it shouldnt be seeling via the threads.... should seal agaisnt the flare surface or via an oring.

KATYB
KATYB HalfDork
8/12/11 6:26 a.m.

and most of conversions ive seen have u leave schadervalve in and on goes over the outside...

ememszi
ememszi
8/12/21 7:49 a.m.

Theoretically yes but you could try something like Locite 577 which is a threadlocker and a thread sealant 2 in 1

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