Fuel Pump Lines Removal 1986 911 3.2 Carrerra

[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 in volume and rate.
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 as always everyone! By the way, I got that fuel pressure regulator out after days of PB blasting and tapping on fuel nuts. Big thanks to John Walker and all others for dialing me in on a plan of attack w/o having to drop that engine.

[rs6er]

I just changed the pump and all the fuel lines in my ‘81 SC with new lines from Len Cummings. The line by the check valve that connects to the fuel tank has to be crimped. When you disconnect the other line, some fuel in the line will trickle out because there is fuel in the line. I don’t remember, because I drained my fuel tank, but you may have to also crimp the short line on the other end of the pump. Others will chime in.


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[famoroso]

First off, let's agree on different nomenclature, as fuel line crimps, or crimping, is something different. I believe the term you want is temporarily "clamping" (i.e. pinching) the short flexible fuel hose from the tank to the suction side (driver's side on a LHD car) of the pump with something like this...



If you do that, and also relieve pressure via the fuel rail test port at the trailing end of the engine compartment fuel rail, near cylinder one (see post that I hijacked from another thread below), you'll only lose a small amount of fuel.

Be cognizant of the condition of the fuel line coming off the tank. Scrutinize it before and after you pinch it. Pinching it may reveal / exacerbate cracking...




Engine compartment test port...

Paraphrased from a RickM post: Here is the cap that unscrews at the end of the rail. Be careful as there's a ball bearing under the cap that seals the port. It will fall out when you remove the cap.


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FWIW, when you've finished your work with the lines (including what sounds like a regulator replacement) you might consider testing the fuel pressure, which would be done at this same port, with a fuel pressure tester / gauge.


A view of the port, with the engine compartment heater blower motor duct removed and a shot with Harbor Freight fuel pressure tester...