[Vwdiesel] Vacuum Pump problems

Sandy Cameron scameron at compmore.net
Mon Mar 1 15:19:04 EST 2004

At 08:28 AM 3/1/04 -0800, you wrote:
>I recently bought a 82 Caddy that you had to push
>really hard on the brake pedal to get it to stop.  I
>rebuilt the pump by replacing the rubber (the old
>pieces were like leather) pieces that you get in the
>kit.  I had good brakes for a few days and then the
>problem was back.  I took the pump apart and the
>rubber was torn completely around the circle plate.  I
>rebuilt the pump again with another kit but I still
>have bad brakes.  I haven't taken the pump apart again
>but I'm guessing the rubber is distroyed around the
>circle plate again.  Any ideas on what is causing the
>rubber to tear around the plates?

YES!. When you install the diaphragm, do NOT tighten the circle of screws
until you  have pushed or pulled the connecting rod to its extremity. The
screws must be tightened when the diaphragm is fully extended, (distended)
in the direction with the most travel (deflection) (it's actually the same
travel in both directions from center), so it will not get stretched when
extended. It is not just plain stretchy rubber, it has fabric molded into it
like a tire sidewall, to PREVENT stretching, otherwise it could not pump. 
. It should be floppy and loose in the middle of travel, but then, you won't
be able to see that with the lid on. :^)


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