The original fuel pump for all of the Silver Cloud and S Type range mounted directly to the chassis with two studs that were part of the fuel pump body.
Two types of chassis mounted fuel pumps were fitted:
All Series 1 models and early Silver Cloud II (before SAE10) and S2 (before B28DW) were fitted with fuel pump DB1935 which had a longer diaphragm RD6881.
Later Silver Cloud II (from SAE10) and S2 (from B28DW) and all Series 3 models were fitted with fuel pump UD8137 which had a shorter diaphragm CD2358.
Both of the stud-mounted fuel pumps have been superceded by Bentley to the Silver Shadow pump UD22715FC which is mounted to the chassis with a fitting kit RH2380. These pumps are listed below under Replacement Fuel Pump.