PS pump cylinder head O-ring seal.
b.benz at charter.net
Tue Feb 19 20:30:51 PST 2008
Repost from <http://forums.audiworld.com/9080/msgs/431403.phtml>
Hi guys. Nothing better to do right now than lurk on this site.
Problem with the rebuild kit parts kit and my original O-ring size
recommendation is that both were designed for the wrong interface
seal surface under pressure. This O-ring under pump pressure must
seal against the ID of bore in the pump housing, not the OD of the
cylinder head. If the latter, the O-ring must be moved by pump
pressure to seat against this bore ID, Not a good static seal design.
Use a 2-019 rather than the previously recommended 2-018 generic o-ring.
Further, when reinstalling the cylinder head with a new O-ring, the
ring must be well greased, not just with PS fluid, to prevent
differential area elongation and resultant localized cross section
reduction because of the cylinder head rotation. This cylinder head
need not be torqued beyond screwdriver tight to provide the required
initial o-ring squeeze.
More information about the 200q20v