cek wrote:Oops, I did it again...
I needed to do this on my 528e (Maytag) and since this is the third time I've done one of these I figured I'd take more pictures and share additional details.
Recall, the idea here is to replace the prone-to-fail in-tank "transfer pump" with a modern, high-performance pump. By doing this you also will delete the main fuel pump that sits by the right rear wheel next to the fuel filter.
You'll need the following:
- Your original OEM in-tank fuel pump hanger assembly.
- Several feet of 12x18 BMW fuel line
- Several feet of 8x13 BMW fuel line
- Soldiering iron
- A TRE "TRE-340" 255 LPH fuel pump (~$79 shipped)
Assembly is easy.
First, take the original rubber connector that goes from the original transfer pump and cut it in half, where the smaller diameter section meets the larger diameter section.You'll use the smaller diameter piece INSIDE your 12x13 tubing to step the size down.
Cut the smaller section into two peices, approximately as shown:
The shorter piece will step down the connector you'll make between the new TRE pump and your hanger. The length of this piece is pretty critical because it is what will determine the overall length of your pump/hanger, enabling the little filter on the bottom of the pump to be all they way at the bottom of your tank.
Slide this over the output nipple on the TRE pump. Slide the other end over the input nipple on the hanger.
Before clamping double check the overall height. In this picture I determined my height was too tall, so I used the shorter piece of tubing you see in the picture above, making it just right.
Get out your soldering iron and de-solder the old power lead. Then cut the new lead to length and solder it in. Solder a new eye-clamp to the ground wire, after cutting to length and use the screw that was already there to affix it.
Use hose clamps (I prefer Oetiker clamps because they are much smaller and make getting the pump into the tank easier).
Make sure the filter is oriented right. Use the original pump as a guide. You want it pointing the opposite direction as the vent inlet nipple on the top of the hanger.
When installing the hanger, be VERY careful because the rubber condom that comes with the TRE pump is fragile and can easily tear.
Under the car you need to remove the original main pump, filter, and hanger assembly.
Tie off the power wires for the original pump and seal the ends up so they don't short out. They'll never be used again.
Use the other piece of tubing you salvaged from the old in-tank pump to size-reduce the 12x18 line coming from your tank to the filter.
Use a piece of 8x13 to curl around out of the filter output to the nipple for the hard-line that goes to the engine bay.
Re-hang the filter, selling the old main pump to someone who, for some strange reason doesn't want to do this awesome upgrade.
Thank you very much for the explanation!
