Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (http://www.hotrodders.com/forum/)
-   Suspension - Brakes - Steering (http://www.hotrodders.com/forum/suspension-brakes-steering/)
-   -   Thread lock on brake fittings? (http://www.hotrodders.com/forum/thread-lock-brake-fittings-195462.html)

staleg 03-30-2011 01:27 AM

Thread lock on brake fittings?
 
Do you use thread lock on some of the brake fittings?
For example the inside end of the thru frame fittings. There are no flare, just plain 1/8" NPT threads.

001mustang 03-30-2011 02:19 AM

in the day many of my threads were rusty. i cleaned then up and used anti seize. on occasion some would loose torque. my garage kept threads don't rust now. i have changed my practice to use thread locking compound on many fasteners including some brake fasteners. i still use anti seize on ss and some aluminum fasteners.

trees 03-30-2011 06:47 AM

Pipe thread fittings are self sealing by design and the brass fittings for brake and fuel lines do not require sealants if they are properly cleaned and in good condition. (Sealants are used in iron fittings are used because of the porosity of the metal and the roughness of the threading action.) If they are not, I replace them. If you notice, any flare fitting uses SAE thread and must be torqued sufficiently to compress the flare for proper sealing. The final torquing of the pipe threads is "compressing" the threads thus providing the sealing function.

Trees

THERACER 03-30-2011 08:53 AM

trees, :thumbup:
i just did the thru-frame dudgies.

trees , i kept tightening the flare fittings (alot to stop leaking)
may have to do a little more to keep from weeping?
do i just keep tighting till they stop? how much is too much?
this a T fitting and flare nut .
thanks

T-bucket23 03-30-2011 08:56 AM

Quote:

Originally Posted by staleg
Do you use thread lock on some of the brake fittings?
For example the inside end of the thru frame fittings. There are no flare, just plain 1/8" NPT threads.

Every brake like fitting requires a flare, if the fittings you have wont accept a flare you have the wrong fittings. Brake lines DO NOT rely on the threads to seal.
Brake lines DO NOT require thread sealant, it is the flare that seals the line not the threads

cucumber1949 03-30-2011 09:33 AM

I think the OP was asking about thread lockers, not sealants. Perhaps he is concerned about having a brake flare nut working loose and allowing the flare seal to leak. He mentioned the through frame fittings (on the inside of the frame) which perhaps could be a bit of work to get to.

I see no problem with using thread locker on the threads making sure the material doesn't contaminate the fluid. I have not used any thread lockers on brake fittings and have never had any come loose. A fastener that has had thread locker applied such as Loctite, when unfastened at some later time, will have to be cleaned up to be re-used, as the thread locker material has a tendency to remain on the threads. Could be a problem on the female side of the fastener.

Frisco 03-30-2011 09:42 AM

Quote:

Originally Posted by T-bucket23
Every brake like fitting requires a flare, if the fittings you have wont accept a flare you have the wrong fittings. Brake lines DO NOT rely on the threads to seal.
Brake lines DO NOT require thread sealant, it is the flare that seals the line not the threads

NOT so! There are several brake line fittings (T connections, thru frame connections, fittings for hydraulic brake light switch) that use 1/8" NPT threads. If the fittings are quality made brass material, no thread sealant should be required. Definitely no locking compound. I have used a single wrap of teflon tape on occasion.

Where a flare connection is used, then NO tape, lubricant, sealer, etc. should be used. A correctly formed double flare will seal without excessive torque being applied. For the poster who asked about tightening (or over tightening) a flare connection, check the flare of the tubing and the seat in the fitting. If the flare is off center it will not seal. If the seat of the fitting has been crushed from over tightening it will not seal and should be replaced. If you are using a single flare for non AN fittings, this style of flare will crack and not seal and is illegal for use on brake lines (with the exception of AN fittings) in the U.S.

T-bucket23 03-30-2011 10:38 AM

Quote:

Originally Posted by Frisco
NOT so! There are several brake line fittings (T connections, thru frame connections, fittings for hydraulic brake light switch) that use 1/8" NPT threads. If the fittings are quality made brass material, no thread sealant should be required. Definitely no locking compound. I have used a single wrap of teflon tape on occasion.

Where a flare connection is used, then NO tape, lubricant, sealer, etc. should be used. A correctly formed double flare will seal without excessive torque being applied. For the poster who asked about tightening (or over tightening) a flare connection, check the flare of the tubing and the seat in the fitting. If the flare is off center it will not seal. If the seat of the fitting has been crushed from over tightening it will not seal and should be replaced. If you are using a single flare for non AN fittings, this style of flare will crack and not seal and is illegal for use on brake lines (with the exception of AN fittings) in the U.S.

A brake lite switch is not a brake line it has pipe thread and is designed to seal with the threads. If you are connecting a LINE to it it needs a flare. All the through the frame fittings I have seen are flared on both sides, how else would the line seal.
Brakes are nothing to screw around with, get the right parts and do it right or you are risking your life

staleg 03-30-2011 10:50 AM

Thank you for your answers. Very useful as always!
I think I have control on the 45 degree double flares and 37 degree AN single flares in my brake system.
It was the 1/8" NPT fitting on the inner connection of the thru frame fitting that worried me a bit.

One more thing.
I'm using a Corvette MC and to make it accept the 3/8" double flare fittings, I had to buy two adapter fittings intended for this purpose.
But one of them seems to not have enough threads? It screws all the way in and I really don't know if it is the flare inside that stops it, or that the threaded area on the adapter fitting simply is too short and stop it that way..?
Any of you with experience on this?

001mustang 03-30-2011 10:55 AM

on flare fittings i still use anti seize w/o issue. no fun removing rusty flare or replacing damaged brake line.

i tighten flare nut pretty firm; tighten more if required to stop leak. even brand new double flares can leak until firmly seated.

never found good data for flare nut or pipe thread torque limits so i pretty much rely on calibrated elbow. i have tried counting turn method but don't have data for all sizes and materials.

i've had bare brass pipe threads leak. i normally use ptfe tape on brass pipe threads and never had issue.

i use ptfe tape or pipe dope or both on pipe threads.

Irelands child 03-30-2011 01:48 PM

Quote:

Originally Posted by staleg
Thank you for your answers. Very useful as always!
I think I have control on the 45 degree double flares and 37 degree AN single flares in my brake system.
It was the 1/8" NPT fitting on the inner connection of the thru frame fitting that worried me a bit.

One more thing.
I'm using a Corvette MC and to make it accept the 3/8" double flare fittings, I had to buy two adapter fittings intended for this purpose.
But one of them seems to not have enough threads? It screws all the way in and I really don't know if it is the flare inside that stops it, or that the threaded area on the adapter fitting simply is too short and stop it that way..?
Any of you with experience on this?


The Corvette MC takes a special fitting - and some of them are metric, depending on the year. If it threads all the way in, it's wrong. I know you are in Norway, but if you can easily remove your MC and take it to a parts store, you might be in luck. Also, some are straight fittings rather then pipe - again, depending on the year/part number of that MC.

I used banjo fittings from Inline Tube(http://www.inlinetube.com/) to plumb this one:

http://i70.photobucket.com/albums/i8...tforpipes1.jpg

Dave W

staleg 03-30-2011 02:19 PM

Thanks!
Both the MC and the fittings are from The US. The fitting threads are correct.
I solved the problem this way:
First I removed the fitting and measured the depth of the hole in the MC and compared this with the threaded area on the fitting. It was very close, but the the fitting was app 2 millimeters (1/13 inch) too short.

I filled the hole with some thin plastic to make sure no dirt could enter and carefully drilled with a large drill a app 1/13" inch down.
The drill was larger than the outer diameter of the fitting. Then I could screw the fitting a little more in and I can clearly see a couple of un-engaged thread rounds. I also feel the fitting hits the flare in the bottom.
No threads in the MC hole was destroyed. I just widened/sunk the part of the hole above the threads.


All times are GMT -6. The time now is 05:47 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.