Tom,
Those gas springs don't last too long any in application it seems.
I have included a link to the vendor I use when I buy replacements. I have been lucky is being able to get the information on spring pressure from the springs I have replaced. It seems to vary depending upon how my bay door is made (bus type or piano hinge type ) as well as the weight of the door.
Hope this help as the prices seem reasonable and the service has been good.
http://www.spdhardware.com/catalog/l...E2E52A3BDA2%7D
Also including this an a short link in case there is any problem with the long link.
http://tinyurl.com/4qfplnq
Russ White - #530