thesaintlyone
Well-Known Member
I'd use a heavy lump hammer and use a socket set extension bar or steel rod as a drift. Spend more time on hammering and less on asking advice. Don't try to hammer them from outside, as has been said, they are coach bolts with a square on the shank so won't go.
There is very little room above the valve and due to the design of the valve itself no room to drop the hammer squarely onto the bolt. So just knocking them through is well add to that the 40 year old sealant that coats everything. Interior Backing plate, Bolts etc