Hello Raf,
Try to drill and tap a hole so you can use a threaded screw where your terminal post was located. Also someone may have a bad pump which you can use for parts to repair your old pump?
A later EFI series Bosch electric fuel pump will work fine. Of coarse the mounting will be different. You will need to mount the pump's intake at the same level as the bottom of the tank. The fuel is "gravity feed" to the electric fuel pump before it is pumped to the engine.
Remember you are dealing with fuel pressure and volume. Many off brand pumps have enough pressure but not enough volume. Your original W113 fuel pump will provide your engine with about 13 to 16 psi. and a liter of fuel about every 15 seconds. This is with a return line OPEN back to the tank. If the line is temporarily pinched off, your original pump actually produces much higher pressure, 30 to 40 psi!! The injection pump has a orifice fitting or check valve to maintain a pressure in the pump before the fuel returns to the tank. In a sense this is the fuel regulator for the W113 system.
The original electric fuel pump on the EFI (electronic fuel injection) Mercedes cars of the early 70's used a Bosch fuel pump which works fine without any modifications. This pump was used on the early W108 3.5 and 4.5 sedans and the early 450 SLs, SLCs and the early W116 sedans with the EFI systems. All the later cars around 1975 used the CSI injection which used a Bosch electric fuel pump which developed as much as 90 PSI in the fuel lines!! You can also use this Bosch electric fuel pump and it is quite common all almost all modern Mercedes and other makes of German cars. It is also much less expensive new and more easily found in wrecking yards. I believe I have seen a procedure on how to use this later high pressure pump in earlier low pressure systems like the W113. I believe it involves, simply installing a couple of "T" fittings back at the fuel pump outlet so another line can be used to route much of the excess fuel pressure and volume directly back to the fuel tank. The engine is supplied with fuel pressure and volume as original to the W113 system. I will try to find the procedure. I may be able to post some pictures a little later also.
Remember that the CSI systems with the latest Bosch electric fuel pumps produce as much as 90 psi. Just putting a regulator on the line will produce pressures much higher than the standard W113 systems are designed for. The fittings and rubber fuel lines and even the filter canister may fail at these pressures. Controlling the fuel pressure must be done not with a regulator but by allowing it to bleed off back to the tank as the original system did.
Joe Alexander
Blacklick, Ohio
