REFLECTOR: Brake Lines

[Dave Philipsen]

While we're on the subject of brake lines I'll just throw in my two 
cents' worth.  I have a STD FG with Nylaflow lines.  The other day I was 
taxiing out to the runway and doing a lot of pumping on the right brake 
due to some crosswind and the fact that I haven't lubed my nose gear 
Belleville washer.  I am not the original builder but my brakes have 
absolutely no heat shields to keep heat away from the gear leg or the 
brake line.  Well, it finally caught up with me.  During my run-up 
before takeoff, I was holding both pedals down and the right one gave 
way and just sank to the floor.  To make a long story short, the 
Nylaflow tubing popped right out of the ferrule and fitting and sprayed 
all of my brake fluid out on the taxiway.  Had to get towed back to the 
hangar.  I figure that the heat caused some expansion/contraction 
problems which caused the line to blow out.  Anyway, I ordered and 
installed a Stopflex brake hose made with a Teflon core, a Kevlar inner 
braid, an elastomer barrier, and stainless steel braid with a clear 
vinyl cover.  They are advertised as having "no volumetric expansion" 
and surpass DOT specs.  The Stopflex line is long enough to get inside 
where a fitting converts back to the Nylaflow for the rest of the way to 
the master cylinder.  I believe that the Nylaflow is ok but probably not 
well suited to hi-temp environments.  So far, the Stopflex modification 
seems to perform as well or better than the Nylaflow that was there 
before in terms of 'soft pedal' or sponginess.



NMFlyer1 at aol.com wrote:
> Need some input:  The original brake "Nylaflow" that came with my kit 
> isn't quite long enough for the 173 FGE.  So, I bought some new stuff. 
> They are the same OD, but not the same ID. The NEW stiff is thinner 
> wall and is too big for the compression inserts that came with the kit.
>  
> The Original part:  S&L Plastics Nylaflow Pressure Tubing Type 3/16"H 
> SK8201
>  
> The New Stuff:  S&L Nylaflow Pressure Tubing Type 3/16"T SK8201
>  
> I am guessing the "H" is Heavy Wall, and the "T" is thin wall.
>  
> The inserts from the factory fit the heavy wall tubing  (that is too 
> short for the airplane).
>  
> The thin wall stuff is what the Wicks and Spruce Catalogs say is used 
> for brake lines. Spruce doesn't have an insert listed that I could 
> find, Wicks has one that says "3/16" part number 2030x4"
>  
> What kind of Nylaflow is being used? If it is the thin wall stuff, 
> what is the part number for the insert?
>  
> I either need to order new (correct) nylaflow, or new (correct) 
> fittings. any input?
>  
> Another screeching stop due to incorrect parts.
>  
> Thanks   Kurt

-- 
Dave Philipsen
Velocity STD-FG
N83DP