71supreme

Hey all,

I hope I am posting this in the right place. I have a fuel leak somewhere in the lines(volume of fuel in tank doesn't drop too much, but it takes forever for fuel to reach the carb), so I am going to do the easy thing first and change all the 40 year old rubber fuel lines. Are they the same diameter all the way back? If so, how much would you estimate I need for my 71 Cutlass Supreme?

If not, what am I in for? Since this stuff usually sells by the foot, my hope was to just get a length of hose the diameter of the one to the fuel pump, and keep using it as needed all the way back.

Thanks for any help or advice you can offer!

Yellowstatue

I believe the hose is 3/8" and you need about 12" at the tank and 3" at the rear of the front tire and another 16" or so from the frame to the pump...try that

MDchanic

3/8" sounds right, and it should be the same all the way through.
You've got extra on the '71 because there's a return circuit.
Just buy about 6' and you should have enough left over to throw some in the trunk just in case.

Also, it does sound like a leaky line - what happens is that the line becomes cracked and porous, and when the pump sucks, it sucks in air through the gaps, making it hard to get enough fuel to the carb. You'll be amazed at how crappy the old hose was .

- Eric

Lady72nRob71

I ~believe~ the short vent lines at the tank may be 5/16". The main fuel line is 3/8"
I remember having to have 2 sizes when I replaced them all.

71supreme

Thanks guys! After checking the hard line and finding no fuel, I pulled the soft line from the pump. It was very soft, and had no fuel coming out when I pulled it, that's what really got me thinking this is probably the way to go.

Thanks for the tip on the 5/16 line at the tank Rob, I'm sure I will see it when I get back there. It's funny, of all the lines I thought to replace this one never occurred to me until these symptoms presented themselves.

71supreme

OK, I replaced the 2 lines up front, and have a question as I look at the 8 or so lines in the back.

Is there a trick to easing the new soft lines onto the hard lines? Since it's a fuel line, I don't want to heat the soft lines, but thought perhaps a little petrolium jelly, or wd-40 might be ok to use. I just want this to be as quick and painless as possible, without any leaks or other complications when I finish.

Any help, thoughts, ideas welcome. Thanks!

rustyroger

WD40 should help, I found having a pan of very hot water to heat the rubber before fitting helps - especially in cold weather.

Lady72nRob71

HEating them a little (100*) in the oven will help and a tiny bit of gas or wd40 can help. Apply that to the metal lines then push and twist the hoses on. I did not have too much difficulty getting mine on and I just put a tad of gas on them.

My442

Use fuel injection hose. It has a barrier inside to protect it against pressure and ethanol.

More expensive but worth it.

oldzy

71's have a return fuel line? My 72 doesn't, just the main 3/8 fuel line, and a vapor line.

Was 71 the last year for return lines?