Along with this list for steps to replace an old Raritan
Painsless head replacement & lubrication. Raritan.
I promised some photographs.
1. After pumping in 4 bowls of fresh water
dry, close raw water
2. Disconnect 4 bolts on the base of the cylinder -> 1/2 cup brown water
3. Remove base of toilet completely, taking care not to spill any water.
4. Put a 2 qt pan under the cylinder & pump and slowly loosen the joker valve.
5. Letting brown water into the pan < less than 1/2 full of water.
6. You're home free now to install the new head
PS: We like the new Raritan
Superflush. Lower bowl more comfortable, larger cylinder is good and pumping action is good. Valves are working nicely and the cylinder valve joker works! I was considering finding a better toilet made with something other than plastic due to bending of plastic at joints over the 23 years, but this toilet appears to be fine.