Van's Air Force
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Brake line fittings
- Thread starter Av8torTom
- Start date
Carl Froehlich
Well Known Member
Yes. I use a Teflon pipe thread sealant like Locktite 567 on all pipe fittings.
Use sparingly and keep away from the first thread.
Carl
Use sparingly and keep away from the first thread.
Carl
Carl Froehlich
Well Known Member
No. Do not use Teflon Tape anywhere on an airplane.
No .... not teflon tape. Use a good sealant as suggested above. Do NOT use EZ Turn fuel lube.
The suggestion to tighten them WAY down is spot-on. Bleeding brakes is enough of a pain, let alone when you have mini-leaks sprouting at the brake pedals. Each newly discovered leak often requires starting the bleeding process all over.
The suggestion to tighten them WAY down is spot-on. Bleeding brakes is enough of a pain, let alone when you have mini-leaks sprouting at the brake pedals. Each newly discovered leak often requires starting the bleeding process all over.
rightrudder
Well Known Member
I second the Loctite 567 recommendation. Great stuff and no signs of a leak anywhere on my aircraft. With those NPT elbows, I'd err on the side of too tight rather than too loose when it's clocked in the final position. Even when they're "snug" it's usually possible to tighten them another full turn.
You might have to mail-order the stuff, but I'm guessing you can get it through Amazon with two-day shipping.
You might have to mail-order the stuff, but I'm guessing you can get it through Amazon with two-day shipping.
alpinelakespilot2000
Well Known Member
There's a Permatex version of 567 that you should be able to find a cross-reference table for in order to identify the exact number.
Av8torTom
Well Known Member
Anyone have any experience with a Loctite 567 alternative that I can buy locally?
Carl Froehlich
Well Known Member
Napa, Advanced Auto and similar places have this under one name or another.
alpinelakespilot2000
Well Known Member
From the Parker site (manufacturer of our wheels), suggests permatex 56750 is an equivalent to Loctite 567.
http://www.parker.com/literature/O-Ring Division Literature/Static Files/Bulletins/ORD5796rev2.pdf
http://www.parker.com/literature/O-Ring Division Literature/Static Files/Bulletins/ORD5796rev2.pdf
BillL
Well Known Member
Warning!
Not with 567! There is a torque spec for this (not handy at the moment) then turn until aligned. This is slippery stuff.
I was very careful about this when installing the oil cooler fitting in the engine case. It won't get as tight as you think, based on plumbing experience. AND . . . this is a 1/8" NPT fitting.
Funny story, my Dad frequently worked on equipment (off road) and is line was "tighten it until it squeaks" . I had some guys who did that with a 3/4" air impact on some wheel nuts on an articulated truck. The wheel fell off! The 3/4" impact only went to 250 ft-lbs (longer story), and the nuts needed 360 ft-lbs. Lesson - never assume.
... and tighten the heck out of it.
Not with 567! There is a torque spec for this (not handy at the moment) then turn until aligned. This is slippery stuff.
I was very careful about this when installing the oil cooler fitting in the engine case. It won't get as tight as you think, based on plumbing experience. AND . . . this is a 1/8" NPT fitting.
Funny story, my Dad frequently worked on equipment (off road) and is line was "tighten it until it squeaks" . I had some guys who did that with a 3/4" air impact on some wheel nuts on an articulated truck. The wheel fell off! The 3/4" impact only went to 250 ft-lbs (longer story), and the nuts needed 360 ft-lbs. Lesson - never assume.
Walt
Well Known Member
Any chance we could get a picture of you torqueing those master cyl fittings to "spec" on a completed aircraft
Measure the depth of the tapped hole and tape the measurement on the fitting so you can see if the fitting is going to bottom out. You might need to file the fitting.
This size fitting should not require EXCESSIVE force.
JanRV6UK
Well Known Member
Thanks all... whoda-thunk it could get this complicated...
Seriously, I really appreciate everyone's suggestions.
Tom
The more people you ask .. generally the more complicated things get
Teflon Paste
One of the major reasons for not using Teflon tape is that it may brake off and clog a opening in an aircraft line. Similar to what might happen with Fuel Lube. But why wouldn't a gob of any thread paste pushed into the end of a fitting do the same thing? Can't see the difference in using Teflon tape or Teflon paste.
One of the major reasons for not using Teflon tape is that it may brake off and clog a opening in an aircraft line. Similar to what might happen with Fuel Lube. But why wouldn't a gob of any thread paste pushed into the end of a fitting do the same thing? Can't see the difference in using Teflon tape or Teflon paste.
Carl Froehlich
Well Known Member
BillL
Well Known Member
Any chance we could get a picture of you torqueing those master cyl fittings to "spec" on a completed aircraft
Not a chance! The point was this: there is a spec from Lycoming, it was a lot lower than my experience with other NPT applications in steel/iron. So - don't tighten it "as much as you can", cause that is a LOT.
We both know that most of this is acquired skill - for those who don't have it yet , open ended, non definitive advice does not serve the unskilled well. Especially when putting slippery lube/sealer on NPT in aluminum.
Experience example: I was doing tune ups in a production VW shop (early'70s). Maybe 25 a week. I was trained to set points to .020" by eye when I was 15, and carried that method to the VW shop. I felt guilty and bought a dwell meter. I used it 2 days and every single time it was on spec. I put it back in the box and only used it for GM V8's after that. How would you describe that over the internet?
