Flaring stainless steel tubing

[yaofeng]

When I took out the final drive of my 540 I saw the fuel lines severely corroded. In particular the fuel return line. BTW I think it is asinine that BMW uses electroplated fuel return lines on the car. The painted fuel supply line is not much better. It is utterly inconsistent with the build durability of the car. If you crawl under your car, you will know what I mean. My SAAB's use plastic coated fuel and brake lines. They are still pristine after 10 years.

Anyway I bought 5/16" stainless steel tubings to replace the fuel lines. My plan was to make a small bubble at the end so the rubber hose won't slip out when clamped. The tubings are 78" straight sections. I was going to make double flare connections between sections.

I found neither works. The stainless steel tubing is too hard. It slips out of the vise grip when I tried to flare it. I think my double flare tool won't fare any better.

Does anyone know if the machine shop can flare stainless tubing for you? Bending the pipe is not that bad I found.


The first section of the fuel return line.


I need to make a reverse flare on the tubing so the hose won't slip out. My bubble flare tool is no good.

[BillionPa]

how do you plan on getting them on there anyway, my return like looks about 3 times more corroded than yours does (thanks minnesota!!!)

[gale]

If all you want to do is have a larger diameter to keep rubber hose from sliding off, you could get a few Swagelok fittings, and use them to swage a ferrel onto the tube. After removing the fitting, the ferrel will stay in place.

[yaofeng]

how do you plan on getting them on there anyway, my return like looks about 3 times more corroded than yours does (thanks minnesota!!!)

The section in the picture is the best part of the fuel return line. That portion is behind the front wheel covered by the wheel arch. I wouldn't have touched it if all is like that. Judging from the portion hidden by the rubber hose connection now exposed, it wasn't even painted. The supply line which is painted doesn't look nearly as bad.