gcthree

I'm about to change the fuel filter on my S4, and after popping the cover and discovering that the last time the filter was replaced was 2004 by way of a sticker on the filter from the shop that changed it.

The issue is that the fittings are not moving. I have the counter wrench 19mm on it and a 17mm to loosen the in-flow side and it is not moving. I squirted it with PB Blaster to soak overnight, but clearly, heat is not an option. Anyone else have this problem? Suggestions!

Thanks,
Bob

Mrmerlin

before you go any further , order the short curved metal line and 6 sealing washers so you will have spares you need 3.
if the fuel pump is old order a new check valve .
if the short rubber hose from tank to pump is old replace this as well.

With your new parts in hand get a pair of channel locks and grip the bulging portion of the short hose just under the cap on the pump hold the line with pliers and unscrew the cap being careful not to let the jaws touch the cap or the pump. the hose will be damaged but the cap will unscrew.


Remove the cap and short metal hose,
and then use a socket on the check valve,
NOTE this is the part that the cap screws onto,
use a new sealing washer and a dab of Loctite PTFE non setting pipe sealant on the check valve threads.
Screw this tightly into the pump, then install a new sealing ring and the new short metal line then another sealing ring, install the cap loose then fit the other end to the filter, add some anti seize to the threads on the line where it goes into the filter, then snug down the filter connection.
Move to the cap and snug the cap dont over do it as you can crush the new bulging area of the new line by over tightening it thus a new line will need to be purchased.

jpitman2

Take the whole pump/filter assembly off the car - only additional work is the R&R of the pump wiring. This makes the wrangling of the S pipe etc a lot easier and safer, you are much less likely to damage anything, and it should be easier to tighten things up properly.
jp 83 Euro S AT 55k

gcthree

Do I need to drain the tank were I to remove the complete assembly and attend to the work that Merlin outlines?

Mrmerlin

with your new rubber hose, get a bolt that fits the hose, then remove the old hose from the pump end,
plug the bolt into it and then remove the pump assembly.

NOTE tie a rag around each of your wrists this will prevent gas from running into your armpits

76FJ55

Yes, you wil need to drain the tank first.

MFranke

No need to fully drain tank, IMO. Remove the whole pump/filter assembly. Pinch initially while disconnecting the rubber line then finally plug the rubber line from the tank so it doesn't leak fuel out the tank. You may get a splash of fuel while doing this but not much. Then you are free to work.

Take the assembly to a workbench. IIRC I used heat without issue once everything was drained and evaporated.

Replace with new or anneal with a torch the old sealing washers.

Ensure everything is suspended on the rubber mounts and nothing is touching when reinstalling the assembly or the pump vibration will transmit louder into the car.