That's all enough information to convince me to go ahead and order a new MC.
Yes...I did stroke all the way.  The good news is I have all new clean
brake fluid in my
system now.  I'll be happy to hear any more opinions, if any one has some.
I'd have probably gone ahead and gotten a new MC if it hadn't been the
holidays.
Just seemed worth the effort to give the old one a shot.
Best wishes and thanks.
'80 Westy Aircooled

John Jensen
johnjensen@johnjensenartist.com
http://www.johnjensenartist.com
bluesbug@verizon.net

On 5/29/2011 3:54 PM, Scott Daniel - Turbovans wrote:
> sure sounds like a 'new' bad used master cylinder.
>
> the poor things seldom get serviced anyway - like lots of old vans have
> 'black water' in the brake system that once was nice brake fluid. ( as
> you
> know...bf absorbs moisture from the air ..
> even just sitting ........eventually it turns to 'just very black  water'
> ..........and water leads to corrosion. )
>
> AND..........I'll bet you right here and now ..
> tell me you *didn't* do this .. !
> you stroked the pedal all the way to the floor in your manual bleeding
> process.
>
> In case you did .........
> One should never stoke the brake pedal all the way to the floor in
> bleeding
> unless it's a brand new cylinder.
> Because ......on an old one, or a used in-service one...since the piston
> never slides down to the bottom in normal use....there's a section of the
> cylinder that gets rough .......from corrosion ..and from the seals not
> sliding over that section, since the brake pedal should never go to the
> floor anyway.
> As soon as you stoke the pedal to the floor on a used MC ...you make the
> seals slide over that untouched area, and that isn't good for the piston
> seals.
>
> I have lots of used brake master cylinders.
> If one works properly after being put on a van ..I consider that just
> good
> luck.
>
> And never ever stoke a used brake master cylinder all the way to the
> floor
> with a manual brake bleeding process.
> ( which I prefer btw, since there's 'feel' involved in the process,
> and you
> can feel that it's actually producing pressure. With a pressure
> bleeder you
> don't get that advantage. )
>
> Scott
> www.turbovans.com
>
>