Pipe thread sealant Question

Is there any particular pipe thread sealant to use between the fuel filter and the fuel pump?

Loctite 567?

thanks
ken

I used Permatex #2 just like used for the fuel tank drain....

Loctite 567 is a good product as long as you give it time to cure.

#2 or my favorite (for 4 decades) , Aviation #3

219PB said:

Loctite 567 is a good product as long as you give it time to cure.

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Great stuff! It's an anaerobic cure, so the stuff that squishes out past the threads is always going to be a little gooey. I try to wipe off the excess as much as possible.

Leaks

I used Perm #2 at first. Then I disassembled, cleaned, and reassembled all fuel and brake lines with Locktite 567 to stop the leaks.

Just out of curiosity, what did you use or do to clean the threads when you changed the sealant?

Pipe Thread Sealant

Napa India Head Gasket Shellac. Works like a charm - after 1.5 years of fighting Brake line "weeps" and a couple of fuel line leaks. Just don't get the shellac on the mating surfaces of the fittings or inside the pipe end.
Let the fittings set for 24 hours before introducing brake fluid or fuel (as appropriate) to the line.

Pneumatic and Hydraulic Sealant

I use Pneumatic and Hydraulic Sealant everywhere except fuel lines. I don't know if it's compatible with fuel, but it works great on brake and hydraulic lines. It's like Loctite and is what heavy equipment manufacturers use on their bulldozers and track hoes.

JDA_BTR said:

Just out of curiosity, what did you use or do to clean the threads when you changed the sealant?

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Permatex #2 and #3 are removable with alcohol. Isopropyl or denatured ethanol. Nothing petroleum will touch it.

BillL said:

Permatex #2 and #3 are removable with alcohol. Isopropyl or denatured ethanol. Nothing petroleum will touch it.

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For an additional data point, I emailed Permatex about the seeming conflict between alcohol cleanup vs gasohol use in the lines. Below is my question and their reply.

Begin quoted text:
Thank you for contacting us. Yes Aviation Form-A-Gasket #3 holds up quite well to fuels containing ethanol.



Regards,



Technical Services

ITW - Permatex







From: Charlie [mailto:[email protected]]
Sent: Sunday, September 25, 2016 1:01 PM
To: Permatex Information <[email protected]>
Subject: New submission from Permatex.com - contact Us



Name: Charlie
Email Address: [email protected]



Message: RE: Aviation Form-a-Gasket #3
TDS says it's safe for gasoline (and I assume that this applies to current auto gas, with 'up to 10% ethanol'). But cleanup instructions say to use alcohol to remove it. Is this product safe to use as a thread sealant in products exposed to auto fuel?

Thanks,

Charlie

To expand on BillL's point, in chemistry the general rule is "like dissolves like"

Alcohol has a definitive terminal -OH group that adds some polarity to the molecule.

Hydrocarbons (oil and gas) are non-polar.

For an example, water (polar) and oil don't mix for the same reason.

mjb

Perm #3 Aviation

Just a (un-informed) guess on my part, but if they say the product is for aviation use, they may not have had alcohol in mind when they formulated it (way back when?). Avgas didn't, and doesn't, have ethanol in it nor do the brake fluids we use in aviation. And the "holds up quite well" response doesn't inspire a lot of confidence for me. No idea what "quite well" means.

Based on my own experience and the information everyone has shared, I'd recommend using the 567 or similar product. We know it works.

Dave,

Did you see my post, with a copy of my question to the Permatex tech team, and their response? The stuff is getting used in auto applications all the time; I bought mine at the local NAPA store. I think it's safe to say that if gasohol was an issue, the millions of auto customers would have made it clear that there was a problem.

Charlie