[alfa] RE: alfa-digest V10 #80

[Mark Battley <M.Battley@xxxxxxxxxx>]

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Date: Tue, 11 May 2004 13:40:13 +1200
From: Michael Findlay <michael@domain.elided>
Subject: Re: [alfa] 105 Benditalia Brake Boosters

You are right to suspect that a failed seal in the master cylinder will 
allow fluid to enter the servo. Replacing the seals in the MC (or the 
whole MC) usually fixes the problem. To my knowledge, the servos do not 
cause much of a problem in themselves. They are usually full of loose 
rusty scale which should be cleaned out but I have not had to rebuild 
one yet. A cleanup usually restores them to working order. A giveaway 
sign of a perforated diaphragm (apart from non-operation of the unit) 
is drawback of fluid into the inlet tract. This occurs when fluid has 
got past the MC seals and then gone further through the diaphragm into 
the vacuum side of the unit. I have also noticed that the servo shaft 
is usually packed with silicon grease which aids the sealing.

Michael Findlay
1971 Alfa 1750 GTV
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Michael: remember it's a remote booster car (isn't yours also?)- there is no
way a failed seal in the MC can allow fluid into the servo, the servos are
in the engine bay, the MC is under the car, the only connection is the
hydraulic pressure line.

The remote boosters do cause all sorts of problems of their own, they are
much more complicated than the normal ones on the end of a MC. The fluid
doesn't have to get past the main diaphragm to get to the inlet tract, the
vacuum hose goes to the hydraulic cylinder side of the diaphragm.

Regards,

Mark Battley
Auckland, New Zealand

1973 Alfa Romeo 2000 GT Veloce (Two stainless resleeved boosters 6 months
ago, just lost boost this week again... Grr)
1989 Fiat Uno Turbo
1999 Fiat Marea Wagon, 2.0 20V
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