Fuel Pump Problem

Troublesome FUEL PUMPS

There's a problem with replacement fuel pumps that left my TR3 dead on the side of the road a couple of summers ago.  I didn't have a camera with me, but I did have a spare fuel pump with me so a ride on the wrecker was averted.  I knew it would only be a matter of time before I ran across another one, and sure enough a willing subject recently presented itself at the shop. 

This particular car was in for another problem and still running, but since the first one bit me, I now know what to look for, and I make a habit of checking these whenever I'm under the bonnet.  You should too, unless you carry a spare fuel pump and enjoy making repairs along the side of the road.

The problem is that the pivot pin which holds the actuation arm into the pump will work loose and allow the arm to stop pumping fuel.  This is on most if not all of the replacement pumps which do not have a priming lever because they were assembled without any kind of clip or distortion to hold the rod into the fuel pump.  If you take a quick glance at the two nuts which hold the fuel pump to the engine, and see any part of a round pin in the vicinity of the nuts as shown by the arrow in this first photo, failure is imminent! (click photo for larger view).  This one moved forward, and the one that failed on my own car moved to the rear, so look at both sides!

Here's another view from down low on the side (this engine is out of the car).  No doubt about it, this pin is working it's way out.  You can see from the exposed end of the pin that there's no provision for a retaining clip, and the end of the pin has not been 'staked' or distorted to keep it in place.

View from inside the fuel pump, and you can almost see that the 'rear' end of the pin has already disappeared into the actuation arm.  It won't be long before it pops out the other side and the fuel pump stops pumping immediately!

Here's a new reproduction fuel pump from Moss (377-000) with the priming lever.  Look closely and you can see that the ends of the pin have a hex shape to engage the priming lever, and have been staked to hold the priming lever in place.  This also offers the added benefit of trapping the pivot pin in the pump, and eliminating the possibility of this type of failure.  If you have a fuel pump without a priming lever, I recommend replacing your fuel pump with one of these at your earliest convenience.  And it looks original too!