Hi again!
Rethinking this again this morning (without the gin but with a hangover!)
the valve, if backwards, would stop the application of brakes when selected
on but I cannot see how it would retain pressure at the wheels.
I probably was talking b#l###ks!
Simon
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Simon Smith
Subject: RE: Europa-List: parking brake system
Nigel,
Are you sure that you haven't got your valve arse about face? If you are
talking about the "MATCO PV-1" then this is the same valve that is supplied
with the factory finger brake kit for the Trigear.
A quote from the factory installation instructions:-
"The parking brake valve provides a means of retaining hydraulic pressure in
the lines between each wheel brake calliper and the valve. When the park
brake is set to "on" a check valve allows further pressure to be applied by
pulling on the brake levers."
The factory kit has the valve orientated with the flow from the finger brake
cylinders to the larger flat face of the valve and then out to the wheels
via the two ports on the smaller face.
I interpret the factory instructions as describing this as a one way valve
that is selectable in or out (of the system) rather than a on/off system.
If you have the valve connected the factories way round then you can select
the valve to park first, then apply wheel pressure which the valve will
hold. I suspect that you are having to apply wheel pressure first, and then
select the valve. Selecting the valve first (if it is installed backwards)
would stop pressure getting from the brake levers to the wheels.
Apologies if I'm talking b#ll##ks
Regards
Simon Smith
504 G-BZTN
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of nigel charles
Subject: Re: Europa-List: parking brake system
--> <nigelcharles@tiscali.co.uk>
I use the MATCO parking brake. It works very well. It is important thet it
is placed in a position where it cannot be inadvertantly selected. As it is
a hydraulic valve it will prevent brake application if it is selected with
the brake off. If it was knocked on in flight no braking would be available
on landing. Whilst the mechanical cam parking brakes are cheaper they are a
little more awkward to use and take more time to make and set up initially.
They are usually designed with teeth so the exact setting will be defined by
steps. Unless these steps are kept small the exact amount of brake pressure
with the parking brake set will change as the pads wear. The hydraulic brake
by contrast will hold whatever pressure is applied by the brake lever.
Nigel Charles
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