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From: "Rumburg, William" <wrumburg@cdicorp.com>
To: 'Graham Nutt' <GrahamN@trace.com.au>, "'lancair.list@olsusa.com'"
	 <lancair.list@olsusa.com>
Subject: RE: Matco Brakes and Audio panel
Date: Thu, 6 Jan 2000 12:34:22 -0500 
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          <<  Lancair Builders' Mail List  >>
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>>
	I see reference to the "old style Matco MC-1 brakes". Does anyone
know how
	to identify which is what and also what is the difference between
the old
	and current brakes. Presumably newer is better (though not always
so)

	Graham -
	   My 1989 320 kit has the MC-1 brakes. Several months ago, I
reported that one of the master cylinders failed suddenly and without
warning during taxi-out. I had "mashed" both brakes prior to starting the
engine and they both checked solid. Failure occured shortly after that
without warning. Luckily, I was at my home airport. Even at 10 mph, that was
an experience. The plane almost did a complete loop before I could shut the
engine off and stop. After disassembling both master cylinders, I was
surprised to learn that the design incorporates a rubber plug which seals
the actuating piston. A poor design, because when that rubber plug fails, so
does the brake. And, it can happen suddenly and without warning. 
	   I requested master cylinder rebuild kits from Lancair, but they
sent new brake cylinders instead. The new cylinders were MC-5's and the
overall design was just different enough that they wouldn't replace the old
MC-1's without modifications. Checking with Lancair, I learned manufacture
of the MC-1had been discontinued in 1992. I can see why. Rather than modify
my installation to accept the newer MC-5, I returned them and received
rebuild kits. I haven't seen the internals of the newer MC-5, but I suspect
they've been designed to eliminate the rubber plug which seals the piston on
the MC-1.
	   My primary reason for writing about this months ago was to alert
others who are flying with the older MC-1's that they are subject to sudden
failure, with no warning. If that occurs at a distant airport, you have even
more problems. The only solution is a preventative rebuild. I would
recommend that at least once every five years.
	Bill Rumburg
	N403WR  (Sonic bOOm)

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