what is the "expansion unit" in my fuel line

[CBradio]

This part #: 16 12 1 120 970

What is it? What is its function?

Recently I got under my car and noticed my fuel line is really rusty,
especially near the fuel pump where it looks like I may be able to stick a pencil through it.

I'm going to change my lines (is this difficult? It seems I can just slide the new ones in, easy peasy, but if this isn't the case, somebody please let me know!)

I'm just wondering whether I may skip this expansion unit item altogether, I'm not sure what it does, its pricey, and the one I have now is also rusted and crumbling.

[Mike W.]

They did things like this for a few years then seemed to discover they didn't really need them. I've seen E23s with multiple devices designed to reduce the pulsations in the fuel feed. But no, you don't need it at all. Not for performance, not for drivability, not even for emissions here in the once golden state.

Fuel line if you're referring to the metal part, I believe comes in a straight piece. Installation is easy, bending to correct shape a little more difficult. Get a tubing bender if it's straight like I think it is.

[CBradio]

Great! I noticed the 528i did not have such an item...

And yes im talking about the fuel lines.

I think they are pre-bent because there are separate part #s for each line...
They are also inexpensive at about 25usd each,
But shipping for the two is almost 100!

Still worth it to replace my rusty lines.

I will order them hopefully this week; ill let everybody know if they were pre bent or not!

Thanks !!!

[Mike W.]

Great! I noticed the 528i did not have such an item...

And yes im talking about the fuel lines.

I think they are pre-bent because there are separate part #s for each line...
They are also inexpensive at about 25usd each,
But shipping for the two is almost 100!

Still worth it to replace my rusty lines.

I will order them hopefully this week; ill let everybody know if they were pre bent or not!

Thanks !!!

That then is the perfect thing to order from a local dealer, they usually don't charge shipping, so even if it's an extra 20%, it's cheaper in the long run. I avoid them too, but sometimes it really does make sense.

[D.]

They're pre-bent.