replacing hard fuel lines

[528i-1981]

Thanks, Robert. I've ordered from Blunt in the past and they've been great, so I'll shoot them an email.

What are the structural differences between the feed and return lines? If the return is NLA, is it possible to modify a feed line to suit? Is it just the ends that are different, or are there differences along the run?

[528i-1981]

They're also really good with email...quick responses.

I sent an email at 10:19 and had a response at 10:22. NLA. I wonder what the difference is between the pre- and post-79 return is?

[Robert Bondi]

Thanks, Robert. I've ordered from Blunt in the past and they've been great, so I'll shoot them an email.

What are the structural differences between the feed and return lines? If the return is NLA, is it possible to modify a feed line to suit? Is it just the ends that are different, or are there differences along the run?

At least you got a quick answer from Blunt.

I saw no difference in the feed and return lines...both formed from the same stock steel lines as far as I could see. One line might be a little longer than the other - note that one line extends several inches farther to the front where they emerge from the frame rail into the engine bay. They may even be more similar length and just staggered a little, although I think they basically end at the same spot in the rear....I may have that captured in recent photos.

The pre-/post-79 difference: My best guess is the difference is at the rear, but don't hold me to that since both my cars are 1977. The later E12s had the pre-pump. I know that's in the tank, but it must lead to a little different routing of fuel hose back there too. I also know the later 528i cars use some right angle fuel hose elbows back there, again suggesting some different routing. I think it would be easiest to tolerate differences at the rear, where several inches of difference could be made up with a little extra fuel hose. Too long would be harder....you could cut the hard line shorter, but then you have to have a means (special tool) to make that bead/flare on the end of the steel line.

[528i-1981]

Helpful, and you're probably right about the in-tank pre-pump.

I think a double-flare tool can make a good end on a hard fuel line. I may go in this direction if the German outfit doesn't come through. They said it would take 4-6 weeks, so we'll see.

Incidentally, the high shipping cost from Schmiedmann is likely because they planned to ship it the way ECS did. Free shipping is a good thing:

[dutch]

I replaced the fuel lines on my 76 carb 528. I made them myself. I used 8mm CuNiFer and used the old lines for shape. Feed and return look the same but the feed line is about 3"longer and it does have a different shape... I found was the factory clips are not forgiving when it comes to shape of the lines. So, where the lines take a turn left or right to follow the floor`s shape, you need both lines to bend in a slightly different location, or they won`t fit the clips side by side... I hope that makes sense...

As for the the end-flares, I used a regular brake line flare tool first step / single flare and pressed the line about half the cycle for a complete single flare. Gets you a nice edge for the rubber line.

[528i-1981]

Dutch - yes, that makes total sense. The lines are run side by side, not stacked on top of each other, so the geometries are slightly different.

Now a battery of follow-up quesitons.

Did you have the rear axle on the car during the refit? Maybeillbuyit raised a PITA flag, and this is a guy with the patience to replace his heater valve lying on his back.
Did you prebend the lines and then fit them or did you do some of the bends on the car?
Any other tips appreciated.

With the old lines and one new I should be able to tackle this. Do you recall what bending tools you used? I need to kit up.

[dutch]

I didn`t plan on removing the subframe when I pulled the old lines, but there were some rust issues down there so it had to come off anyway. I don`t think you do yourself a favour with the frame in position. I do think it could be done on a lift when the frame is dropped an inch or two. I pulled my old lines in 2 pieces and even that was a struggle to get them out. There is one clip above the diff which is really hard to get to to loosen the screw. Personally, I would just drop the frame. It will save time & headache.
I prebend both with just a simple El-Cheapo brake line bender , a ruler and a marker... and patience. I only used the bender for the serious bends. Light bends I did with the thumbs. Minor adjustments were made on the car. A couple helping hands would help when bending and checking shape.

[Robert Bondi]

Main advice on the bending tools is to have multiple options....no one tool will do everything was my find. I had a picture earlier in the thread...most used tool to straighten back to the factory bend was that fairly cheap Performance Tool bender with the red handle. I guess from the giant ECS box you won't need to uncoil and straighten.....

[528i-1981]

I never was able to source the return, so I'll be making that one. I bought nickel-copper line which should be easier to bend than steel. I found a cheap beading tool for 8mm tubing.

Dutch is right about having the subframe off for this job. I'm also replacing the gas tank, so with that also out of the way it's wide open under there, which gives me the chance to tidy things up a bit. There are a couple little hard lines back near the pump that now can also now be easily replaced. As well as some crusty brake hard lines. A few small rust spots but not bad at all for a New England car.

[maybeillbuyit]

Robert, thx again for posting this. I just ordered both pipes for my 77. $60 plus $12 shipping. Seems almost silly cheap. I've just been replacing prebent brake lines on my Toyota Tundra and I'm up to about $500 for about 6 lines. And those lines are made in Kentucky. I'll be storing them till I drop my rear subframe for a big refurb/suspension refresh. Nice to see some guys still on here.

[528i-1981]

I'm rounding the corner on my rear axle rehab and fuel tank replacement. The entire fuel pump/filter set needed some love as well. I'm just waiting on some additional hardline to finish up.

[Robert Bondi]

Looks great! Is that a fresh coat of black paint on all that steel or other? I swapped in a bunch of powder coated rear suspension parts while I was back there on the restoration car.

[528i-1981]

It's POR-15. The prep is a total PITA but way easier with the axle off. I've had some bad outcomes with POR-15 but always because I wasn't anal about the prep. POR-15 also does best out of direct sunlight - I did buy some chassis topcoat that I can apply later if it loses its gloss. I would have loved to have powder-coated the whole thing but that's a different level of commitment.

Lock swapped an E28 rear axle into his E12 and I still have a twinkle in my eye to do that someday. I picked up the required diff cover from eBay for when I run out of projects and the right donor car magically appears.

[528i-1981]

Car is back on the road. The only hitch was that the feed and return hoses were criss-crossed above the tank, so that when the tank was bolted up the feed line was crushed. Keep the hoses parallel above the tank, and also keep weatherstripping from where the hoses are. It may also seem obvious, but cut hoses long and trim in place (amhik).

[Robert Bondi]

Sounds like some worthwhile work on the fuel system. I've got a new Euro gas tank queued up when I shift my focus to that spot.

Yeah, I've never really had POR15 fail if prepped properly. Sometimes it's not quite possible to get adequate prep
into the very tightest spots. I always topcoat it with something....Rustoleum at minimum.

Even powder coating can have issues. In my most recent batch, the guy I've been using for several years skipped a bunch
of the requested masking. I've spent too many hours with Q-tips and MEK, razor blades, Dremel wire brushes, etc....