Gerber Ceramic Cartridge Install

[Tso1ab]

I've got the old compression cartridge out of a 70’s Gerber shower valve and am about to install a ceramic (Gerber 98705). But first, do I need to remove the compression seat? If so, is there a different seat for the ceramic?

 

[hj]

Normally a ceramic stem does NOT need a seat, but for a conversion sometimes it does and other times it does not, and you may have to try it both ways to see what works, but if you do, try it without the seat first to avoid damage to the stem.