This thread will never go away.
I'd say pinch it or pull out the head shims to help regain compression.
If you need to replace it I would recomend the STS .28 it is allot cheaper (70.00uk on Ebay) than the SH and has allot more power.
http://cgi.ebay.co.uk/STS-28-PullSta...QQcmdZViewItem
or
http://www.racernine.com/sts28.html
rolland