Fred, Thomas,
We've seen this failure in a similar installation on a Glasair II, where the
construction manual called for "nylaflow" brake lines from brake master
cylinders all the way to the calipers. After an instance of heavy braking
and heating up, the nylaflow line softened and folded over, causing the
brakes to fail. Fortunately, an experienced test pilot was at the controls,
so no damage resulted.
Our suggestion is to terminate the plastic or nylon brake lines just above
the brake caliper and join with a union fitting to an Aeoquip-type brake
hose of the sort that is steel braided tubing wrapped in a rubberized cloth
braid, rated to 3000 psi. We allowed a 16-inch flex hose to accommodate a
360-degree service loop so that the brake calipers were free to move about
with pad-wear. We feel this is better than a hard aluminum line.
Cheers,
Larry Graves
AirCrafters Builder Assistance Center
5810 Obata Way Unit 7 Gilroy, CA 95020
Tel 408-847-5957 Fax 408-847-6957
www.AirCraftersLLC.com
----- Original Message -----
From: "Fred Fillinger" <fillinger@ameritech.net>
Subject: Re: Plastic Brake Lines
> Thomas Scherer wrote:
> >
> > When I was flying my Trigear to Southern France over the weekend
> > I had a failure of one brake: the brake line jumped off the elbow
> > fitting on the port wheel.
> > (snip)
>
> Has anyone else had such a failure? I am a bit
> suspicious of these plastic lines for my
> tri-gear. Is this black, nylon-like stuff used on
> the monowheel?
>
> Besides the integrity of the connection, I've read
> on the Lancair mail list where similar tubing they
> supply can get brittle and crack at the brake
> caliper (due to heating/cooling cycles). There is
> a variant of Murphy's Law that says were a brake
> line to fail while maneuvering on a crowded ramp,
> the most difficult to repair part of the Europa
> will strike a similar part on the most expensive
> jet on the ramp.
>
> I was considering substituting aluminum tubing,
> with appropriate AN fittings. Has anyone done
> this?
>
> Regards,
> Fred Fillinger, A063
>
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