Removing Fuel Pump LInes 1986 911 Carrerra 3.2

[Greg Greer]

I am attempting to remove my fuel pump check valve on my 1986 911 Carrerra 3.2 and want to make sure I clearly understand what I am getting into. I have heard to crimp or block the fuel pump line to prevent a gas spill. Does this refer to the short rubber hose on the driver side of the fuel pump that runs from the fuel tank? I have not taken this off yet, unsure of what kind of fuel leak to expect.
I have the nut loose on the passenger side of the fuel pump at the banjo fitting. This banjo fitting appears to be connected to a line goes to the rear of the car. It started seeping fuel when I loosened it, so I snugged it back up for now, unaware of how much fuel to expect.
Which side needs to be crimped or blocked, or both?
Thanks guys as always!

[Tom]

I am attempting to remove my fuel pump check valve on my 1986 911 Carrerra 3.2 and want to make sure I clearly understand what I am getting into. I have heard to crimp or block the fuel pump line to prevent a gas spill. Does this refer to the short rubber hose on the driver side of the fuel pump that runs from the fuel tank? I have not taken this off yet, unsure of what kind of fuel leak to expect.
I have the nut loose on the passenger side of the fuel pump at the banjo fitting. This banjo fitting appears to be connected to a line goes to the rear of the car. It started seeping fuel when I loosened it, so I snugged it back up for now, unaware of how much fuel to expect.
Which side needs to be crimped or blocked, or both?
Thanks guys as always!

This link may help:

https://blog.fcpeuro.com/how-to-change- ... orsche-911

The pump and hoses are full of fuel, so you will always see some fuel drip out when you undo the banjo bolt. You could plug or clamp that line, but the amount of fuel 'should' be small enough to catch with a drip pan or rags, and some is going to drip out the pump no matter what you do. (Disconnect the battery first, have fire extinguisher nearby, and no source of sparks, etc.) The short hose on the fuel tank side is open to the tank, so if you don't block that one, it will keep draining gas until the tank is empty. That's why most instructions say to block that one, or better yet start with an empty tank. Personally, on older cars like this, I don't like to clamp old rubber hoses. That might work fine on new pliable rubber hoses, but on older, harder rubber lines, clamping the lines puts them at risk of cracking. Even if you can't see the damage, they can start cracking on the inside and eventually fail. I'd run the tank down to a gallon or two, then drain it into a bucket to do your work, and I'd still probably replace the tank-to-pump hose it's original.

See the leak on my '86 944 below, and note how the crack/leak started on the inside of the hose....

inside hose crack.jpg (976.25 KiB) Viewed 461 times

[Tom]

p.s., why are you changing the check valve?

[Greg Greer]

It's one of those, "While you're in there" cases for a hard start condition. I have already extracted the old fuel pressure regulator (Ugh). I have replaced the cylinder head temp. sensor, which tested bad. The speed and reference sensors tested good for specified resistance. I have spark.
So, while waiting on fuel pressure regulator parts, I read of the fuel pump check valve also causing starting problems & residual fuel pressure leak down. In the meantime, I decided to replace it too . The hardest part has been unseizing all of those stuck fuel line fittings. I have been PB blasting, 'Kroiling", and tapping on fuel nuts & belly pan nuts for days. I'm pretty sure these are the original factory parts, but finally have them all unseized. Maybe I should just replace the old fuel pump too, "while I'm in there", hee, hee,?!