Jeep fuel pump update

[motto (RIP)]

I purchased a Dodge Weapons Carrier many years ago that had been fitted with an electric fuel pump wired to run whenever the ignition switch was turned on. It was a 12 volt truck so the battery was in a stowage box in the tray body and the battery lead passed through the pedal mount area as does the fuel line.

One day when I was manoeuvring the vehicle close to the house I stalled the engine and when I pushed the clutch pedal down there was a very audible arcing type noise and the amp gauge flickered wildly. I got out and lifted the bonnet to have a look and was shocked to find the battery lead had shifted and been rolled between the clutch pedal arm and the edge of the chassis which had peeled the insulation off. There were flash marks on the nearby fuel line which was a copper replacement.

If luck had been against me I could have blown a hole in the fuel line and the Auto Pulse would have worked its little heart out to feed the fire. There was a distinct possibility of loosing not only the vehicle but my house as well.

Modern vehicles with electric fuel pumps have to have them powered in such a way that they cease operating if the engine stops so as the fuel supply ceases in event of an accident.

In regards to WW2 vehicles, the original mechanical fuel pumps with hand priming are perfectly adequate if in good condition. The greatest exception to that is the Ford V8 side valve which was notorious for vapour lock.

Richard's advice on diaphragm removal is good, there is a knack to it. Particularly if the pump is fitted with the stem seal that prevents fuel getting into the sump in event of diaphragm failure. I find that if you hold the pump in both hands you can use both thumbs on the metal disc to push against the spring and also toward the pump mounting face to unhook the stem from the pull arm.

Reassembly is more tricky as the pull arm falls to the bottom, away from where you want it. I hold the pump upside down overhead. It also helps to hold the cam follower in against spring tension. You will figure it out.

David