I got an 2003 produced apollo 1st stage,it doesn't work,when i dissassamble the hp seat ,i foung the seal rubber (looks like PU)has rot,i removed the rot sealant,now I want to replace the hp seat,i got some pu material ,and cut a shape to match the seat gap( the PU washer located where black material in the picture,) ,but can not adherent the new sealant to the hp seat body,maybe I need some powerfull gluse?have any diver repaired this part before ,you can share some infromation ,and the poppet valve is same like belowe pics.