[Vwdiesel] Vacuum Pump problems

[Gary Shea]

Hey guys.  More on the vacuum pump rebuild problem.  I _think_ my second
replacement shredded a few hours after I installed it, and that's after
taking Sandy's advice and 'pre-tensioning' it.  So... I must be doing
something really stupid but... what?

You'll recall the diaphragm has a flat lip and bubbles up in the middle.
I'm putting the bubble on the same side as the screw heads (I think of
that side as 'up').  There are two plates (like Loren describes below),
one on each side of the diaphragm.  Each plate has a dished edge and the
dished edges are turned away from the diaphragm, so the plates are
concave in opposite directions away from the diaphragm.  On the first
replacement diaphragm I tightened the nut down tight so the plates
gripped the diaphragm firmly; this time I left 'em kind of loose.  Last
time I think the diaphragm lasted like two days instead of a few hours.

I would say tha the bushings are pretty tight, at least to
finger-wiggling.

I'm baffled...

        Gary


On Mon, 1 Mar 2004, at 11:44 [-0500], LBaird119 at aol.com (LBaird119 at aol.com)...:
> Any ideas on what is causing the
> rubber to tear around the plates?
> 
> 
>   The "plates" are dished sort of.  The outer edge is lipped up.  Were those 
> facing away from the diaphragm?   If not that could tear it.  Otherwise I 
> can't really think of anything that would unless there's a shot bushing in 
> the pump letting the portion that runs the diaphragm, work up and down 
> or side to side rather than straight up and down.
>      Loren