Take it to a professional shop that can pressure bleed the system.
Master cylinders should last many years.
They are a fast moving inventory item and I doubt that you could possibly
have gotten two bad units. (unless they came from Pep Boys , Chief Auto
Parts or one of the known to sell those high quality made in China
parts.)

Stan Wilder

On Sun, 15 Dec 2002 21:50:28 -0800 michael johnson
<gatorxray@EARTHLINK.NET> writes:
> Somebody please give me some input.
> Replaced the 2nd master cylinder today. New seals on the front
> calipers(didn't need them)new rubber brake hoses,new rotors and
> pads. Rear brakes appear to be fine. No leaks.Drums and shoes are
> not new but plenty of lining remaining.
>  The pedal is still very soft and very little change (little) after
> you pump the pedal 2-3 times.
> Checked the brake servo and it passed along with the one way check
> valve.
> I suspect either my brake pressure regulator is failing or I am on
> my 3rd bad master cylinder.
> HELP !
>
> gatorxray@earthlink.net
> Mike
>
>

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