butchmalloch

can i eliminate the dual function reservoir? what does it do exactly. leaking like crazy now.

klricks

The DFR is the dual tank switching valve. There is a diaphragm type value inside which is operated by fuel pressure from the low pressure pump inside the selected tank.
The DFR also acts as a reservoir to keep fuel flowing in extreme 4x4 maneuvers where the tank pump could momentarily draw air.

There is also a fuel filter inside which you can change by unscrewing the DFR. There is an 'O' ring between the 2 halves which could leak if it is bad.
(Note that not all versions have the filter).

If the DFR is broken or one or both of the in tank pumps are not functioning, then excess fuel returned from the engine EFI could be returned to the wrong tank and/or other issues such as bucking etc.

I replaced the DFR on my '86 302 with an electric type switching valve and added the biggest in line fuel filters I could find to sorta act as a reservoir.