AC Delco Fuel Pump Assembly
Posted: Sun Nov 29, 2015 9:16 am
I read recently that when assembling the diaphragm on these pumps, you should bias the rocker arm upwards to bring the diaphragm down level with the pump flanges while you tighten the flange bolts.
Needless to say, I did not do that when I refurbished and the pump is back on the car, and working OK.
After some head scratching as to why you need to do this I reasoned that the diaphragm must be stretched upwards on assembly if you leave the rocker arm down, This puts slack in the diaphragm when the pump is working which might affect the pumping action.
I am telling myself that the replacement red diaphragm is elastic rubber rather that the old composite black diaphragm, so this does not matter so much. I can see the edge of the new diaphragm is flush with the outside of the flanges. So should I leave well alone or re-assemble the pump (which means taking it out again) ?
Dave Chapman
Needless to say, I did not do that when I refurbished and the pump is back on the car, and working OK.
After some head scratching as to why you need to do this I reasoned that the diaphragm must be stretched upwards on assembly if you leave the rocker arm down, This puts slack in the diaphragm when the pump is working which might affect the pumping action.
I am telling myself that the replacement red diaphragm is elastic rubber rather that the old composite black diaphragm, so this does not matter so much. I can see the edge of the new diaphragm is flush with the outside of the flanges. So should I leave well alone or re-assemble the pump (which means taking it out again) ?
Dave Chapman