You can actually replace a couple of the non-collapsing ones that are near
the edge, but I would recommend going with the collaspible ones.  They are
$19 each, but they work excellent.  I have used them many times with no leaks
and I have pulled engines that have had them installed for several years, and
no leaks.  

Thanks,
Ken Wilford
Van-Again
John 3:16
http://www.vanagain.com
Office: (856)-765-1583
Fax: (856)-327-2242