Originally Posted by glenncof

1985 Porsche 911 – at 198K miles


1) Remove the fuel pump fuse as extra precaution.
2) Remove splash pan under the front – 8mm hex and 17mm socket.
3) Pump is located on a cross member behind fuel tank. Remove cap holding banjo connection using 19mm socket with 17mm open-end wrench to hold check valve. Very little gas came out as pump stops gas coming from tank.
4) Two copper washers are used, one on each side of banjo fitting. I reused them after sanding since small ridges could be felt.
5) Nuts on the terminals are 7mm and 8mm wrench size, studs different sizes so +/- don’t get mixed. Note the orientation of the terminals for reinstallation, my small + terminal was down.
6) I did not replace crimp-on terminals, instead cut old boots off with diagonal cutters. Cut new boots to slip over old terminals and sealed with small zip-tie.
7) Squeeze inlet hose to limit gas flow from tank. I used needle-nose vice grip since jaws were flat.
8) Remove inlet hose from pump. A small gas drip was stopped using the rubber cap covering the check valve on new pump.
9) Remove old pump and replace with new. I sanded the + lug due to small corrosion and covered it with dialectic grease before fitting the boot. Connect terminals before tightening pump strap for better access.
10) Cut the ½” replacement hose to length. Porsche says 90mm length, mine measured 4.0 inches. I connected the hose/clamp before installing pump.
11) Keep pump strap loose. Remove old hose from tank and quickly put your finger on the tank connection. With the pump/hose in place I was able to connect it to the tank losing only a table spoon of fuel. Have a new clamp on the hose before connecting it as the ½” hose will leak somewhat (maybe it should be 12mm).
12) Tighten pump strap and connect banjo fitting/copper washers with cap nut.
13) Replace fuse and turn ignition on to build pressure and check for leaks.

Note: You can measure the pump circuit from the fuse block with ohm meter but you need to remove the fuse otherwise something (DME?) gives you ~5-10ohm reading even if pump is open. The resistance of the new pumps was ~7-8ohms.