Rob writes:

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Brent Regan recommended Parker PDH-2. It is a
1/8 ID  X 3/8 OD flex hose with nylon / kevlar / polyurethane
construction. It can be bent in a 3/4" radius and cannot be kinked.
It's burst pressure is over 12,000 psi. In another post he said
that DH Instruments (http://www.dhinstruments.com) (800 414 9990)
manufactures a flexible test hose that is only 0.19" in diameter.
It has a 0.080 bore (plenty big enough for brakes), 20,000 PSI
burst and is tested at the factory to 6,000 PSI.

 >>
Thanks for the detailed information.
To expand on it, the Parker PDH hose requires some grinding on the
inside of the gear leg to get it past the trunion pin. Regarding
diameter, the DH Instruments Hose is a direct replacement for Nylaflow,
so it is preferred. The correct DHI part # for a IV is F3737-60 (60"
long with two 37 degree female swaged flare ends) and the last price I
have is $80 per assembly. You will have to disassemble the gear leg and
press out the trunion pin to install the tube but it is effort well spent.

Given that a brake line failure WILL result in an "Off Tarmac
Experience" I believe it is foolish to depend on that naked fish tank
tubing supplied in the kit. Spend the $160. Live longer. Sleep better.

Regards
Brent Regan