Unless you are removing the heads you will have to use the 2 piece spring loaded tubes. If the heads have been in place long enough for the tubes to rust through  then you should plan for their removal for some reason in the future. As such I would only replace tubes that have actually failed.

Dennis,
And I still can't type on this Windows 8 Phone!
________________________________
From: Dean Staltare<mailto:predsmaniac@GMAIL.COM>
Sent: ‎3/‎18/‎2013 12:06 PM
To: vanagon@GERRY.VANAGON.COM<mailto:vanagon@GERRY.VANAGON.COM>
Subject: push rod tubes dilemma

  Hello to all...looks like new push rod tubes will be need to be
replaced on my 85 westy..any and all recommendations/comments and where
to locate these tubes would greatly be appreciated. Although 2 are
leaking/rusted, I will replace all 8 at same time.

Much thanks to you all. DS
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