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kschitoskey · 02-05-2023, 07:36 AM

I'm in the final stretch with my FASS instal. I mounted it in engine bay to L of primary fuel filter. My question is this: I have all these fittings and some leftover 1/2" fuel hose. Can I replace the line going between my FASS and the secondary fuel filter with 1/2" fuel line? Will that be enough to feed an 8.3 ISC? I know the stock is slightly larger with 10 AN fittings. I appreciate the ease of putting a union on the original fuel lines by the now-unused lift pump, but the idea of replacing the 24 year old fuel line with new is quite tempting.

jacwjames · 02-05-2023, 08:11 AM

Hard to say as the original configuration relied on first the transfer pump to push fuel to the filter and then after it shut off the CAPS pump to pull fuel all the way from the tank.

My gut says you'd be fine but personally I wouldn't do it. Not worth the risk.

When I installed my FASS system I was reluctant to use the hose for the supply side since it was not a reinforced type hose. I was afraid that over time it might become soft/pliable and with the suction might collapse. So I went to NAPA and had a hose made using wire braided hosing. I did use the hose for the return side that sends excess fuel back to tank, I didn't feel there was much risk there.

zmotorsports · 02-06-2023, 09:56 AM

Personally, I prefer to use steel braided fuel line on the suction side to prevent collapse such as Jim mentioned.

kschitoskey · 02-06-2023, 07:24 PM

Good advice - thank you. I'll confine the use of the push lock tubing to the pressurized side (post-FASS) in the engine compartment. In the interest of fewer restrictions I went ahead and sourced some 10AN fuel line and fittings to complete the FASS ->secondary filter setup. Would probably have been OK with 1/2", but I figured the coach builder used 5/8" line for a reason. At least peace of mind for me. Thanks for the replies.