Brake line fittings on fuselage really needed?

[ChiefPilot]

One of the tasks I started to tackle tonight was running the brake lines from the cockpit to the wheels on my -6A. I'm passing the brake lines through the side of the fuselage just aft and below where the fuel line penetrates the fuselage, and it occurred to me that instead of putting fittings there (possible leaks) I might instead simply use a single piece of aluminum tubing to go all the way from the wheel to the firewall with a grommet used to isolate the line from the fuselage side wall.

Before I do this, however, I am curious if there is a good reason I shouldn't be doing this? The only reason I could come up with is possible heat, but I don't think the line would get so hot it would adversely affect the grommet.

[D-Dubya]

I'm thinking that Van's has the firewall fittings and a doubler there for a reason. The brake hose moves (albeit not much), and something needs to anchor the brake line tubing from the pedals to keep it from sliding back and forth through the firewall.

If you're comparing it with the fuel line penetration at the sidewall, it's somewhat different. The fuel line is fixed at both ends (the tank and the fuel valve), meaning the only real movement the tubing sees at the grommet is from vibration.

Others may have different experiences, but that's my two cents' worth.

[ChiefPilot]

This would not be going from the pedals directly; there is a parking brake valve on the firewall and the lines would be snaking from that valve through the center tunnel on the floor and then left/right to the fuselage sides with adel clamps holding the line along the way.

[D-Dubya]

Well that's a somewhat different situation than I had pictured. If the tubing is fixed and the grommet has proper firewall protection--just like a wire penetration--then it might be okay. I'll be curious to see what others say.