Glas 1700 GT: rebuilding the fuel pump

Update: I made a little Glas GT dedicated page above -check it out!

The Glas GT has a Weir type fuel system similar to the Porsche 911’s.  Two single throttle-body Solex carbs are fed from a remote float chamber.  Fuel pressure is maintained by a pair of mechanical fuel pumps operating off the same shaft.  I haven’t worked out the fuel path yet but it looks like one pump keeps the float bowl fed from the gas tank, and the other pumps fuel to the carbs.

The finished product -well, almost, I still need to make some paper gaskets and get some little copper crush washers.  Filter chamber covers have been plated and polished, screws just plated.  Very nice!

The diaphragms.  As they move in and out, fuel is pushed through a one-way valve.  Gas tank sits higher in the car than the pump so gravity keeps more fuel waiting to be pushed through that valve.  These are available at about $40 each -good thing these are serviceable.

Fuel comes in the big orifice at about 10 of the clock via the bent tube.  Goes out the through the straight line.

While I cleaned up the body parts of the pump, I plated the screws that hold it together.

Here’s the pumping linkage.  Tiny little C clips on a tiny pin used as the lever pivot, and the lever itself.  That green bit in the background is part of one of the seals I need to cut. 

Big part at the top is the pump rod housing.  The part on this side pushes on the split levers, the other side has a rod that projects into the engine and is driven in and out off a cam lobe on the distributor drive shaft.  In the foreground are the filters and filter housings fresh from the plating tank.

Some of the bits get assembled.  The seal I need to make goes between the filter housing cover and the filter seen here.  Originals were made of paper.  I’m thinking the seals can be cut from the Alfa Weber DCOE to air-box gaskets in the background -ID of the opening is perfect!  Plated screws look great.  It’s a sacrificial zinc coating that should last years -but not stay this shiny.

A single shaft presses on 2 levers -one of which is installed here.  It lifts the shaft of the diaphragm and pumps the fuel.  This chamber was full of hard old grease.  Now it will be full of nice new red grease.

All together now.  The other side of the finished product.  No one will ever see those plated screw heads, but I know they look good so there.

It’s a small thing, but it’s the first step towards a finished car.  A sub-assembly all ready for action.  Up next, the head, the starter, the cam box or?  Lots to do!

Need some work done to your Glas GT?  Drop me a line!


1 thought on “Glas 1700 GT: rebuilding the fuel pump

  1. Hi there
    Very interesting pump set up.
    How did you go about to restore / replace the diaphragms? I have to get a new diaphragm for my Giulia fuel pump and they are no longer available as spares.
    Thank you and cheers,

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