I worked at PCL until 1989 making footpumps. The leather cupseals worked well and were soaked for a few days in "G" oil to soften them.
Leather was prefereable to rubber as the rubbers hardened and rotted if lubricated with motor oil.
We continued using leather until the EU introduced some...
The Turner bothers fell out in 1930s and the younger brother set up in competition on John Street in Sheffield.
The company's name was Pneumatic Components Ltd. PCL. They manufactured footpumps and airgauges and are still in business.
I have a large collection of Kismet & PCL footpumps including...