This is the valve head from the Fuel Delivery Module (FDM) used in '90-04 F-series & Broncos (and some other Ford products). This one is the first I've found in good enough shape to dismantle its valves. All the others have been abandoned for so long they're caked in stale gas varnish.
Surprisingly, the shuttle valve isn't stuck - the problem is the ruptured diaphragm that operates the shuttle valve. Apparently, it worked enough to let fuel return when this pump was running (as it should), but it also let fuel from the other pump leak in, and flow thru the venturi into this tank. The symptom was that THIS tank was able to run the engine, but it struggled when using the GOOD tank (because the good pump's fuel was leaking into this tank).
In any case, there is no repair - the FDM must be replaced, and even the cheapest ones come with a new fuel pump. Fortunately, the pump from this one can be saved for when the new one goes out. The best new FDM (when the Ford/MC isn't available) is Bosch, but only those made in USA (not Brazil). All '90-04 F-series front tanks & all '90-96 Broncos take
67000; F-series rears take
67003.
Alternatively, ANY working FDM top plate can be swapped in, making a junkyard fix very tempting. That's how I fixed this one for a several years.
See also:
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To temporarily or permanently convert a '90-up 2-tank truck to a single tank, read this caption:
