View single post by UKJames
 Posted: 09-20-2014 07:38 pm
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UKJames

 

Joined: 04-24-2014
Location: Berkshire, United Kingdom
Posts: 42
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The vacuum doesn't recover, drops off sharply for the duration of the full down brake pedal (that's the noise I was hearing). Recovers immediately the brake is released.
I suspect the output seal is partially worn, and only lets go when the push rod is extended. I guess these seals must get a fair bit of wear in normal use, they're not lubricated. Visibly the seal looks in very good condition... I'm not sure if you can replace it easily.