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Fuel Hose Replacement FAQ

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Courtesy of Adam Wilson

INTRO

This FAQ is intended to give some guidance on replacing fuel hoses in the E12 5 series. I'm assuming that there isn't any difference with the hoses or part #'s for the different year E12's, but for clarification purposes, this procedure was performed on a '80 528i and an '81 528i. The pictures used are a mix from these two cars.

NOTE:While very straightforward, you will get very dirty, cramped, and smelly from doing this job. You WILL get gasoline on at least your hands and probably your shirt and clothing as well. Some kind of eye protection would be a good idea in case gas were to spill out of the old hoses into your eyes.

NOTE:Your best source for these parts is your BMW dealer. Don't skimp on fuel hoses, BMW makes excellent quality fuel hose and you definitely won't want to do this job again anytime soon. They most likely won't have all of this stuff in stock so order it ahead of time, and be sure to get your CCA discount by presenting your card when you pick up the stuff.

This is what old fuel hoses look like! Don't continue to drive your E12 around with fuel hoses that look like this.
This is a picture of the 16 12 1 180 409 hose, along with the elbow bend version of it (16 12 1 176 821).
This is a different picture of the 16 12 1 180 409 hose lengths as well as the fuel filter.

MATERIALS

quantity part# length or size description
one 16 12 1 176 440 1 meter/$14 each thick diameter hose coming from in-tank fuel pump to fuel pre-pump by wheel well
one 13 32 1 270 038 $20 fuel filter
three 16 12 1 180 409 1 meter/$10 each smaller diameter hose used for majority of work
three 16 12 1 176 821 elbow/$3 smaller diameter hose but in a preformed 90 degree elbow configuration

Also, buy about a dozen hose clamps. They're cheap, you'll definitely encounter some hose clamps that are rusted and could use replacing, and any extra will find a good home in your tool box Buy the ones that will fit around the "16 12 1 180 409" hose, and maybe buy 2 of the bigger ones for the "16 12 1 176 440" hose.

FRONT HOSES

The first hoses to tackle are the two lines running into the engine compartment. One comes from behind the intake runners near the firewall and the other from the fuel pressure regulator near the fan blades. The best thing to do here is to do them one at a time, so you don't confuse the two when you replace the hoses. Remove these fuel hose ends by loosening the hose clamps, and pulling the rubber hose from the mounting. Some gas will leak out when they are removed. Now, both hoses go towards the brake vacuum booster and dive down to the hard lines mounted below the engine compartment. Looking down from the top of the engine compartment, the points where they meet can barely be seen. These mount points can only be accessed below the car. To do this, the car must be jacked on this side (drivers side) and you, the unlucky mechanic, must wriggle under it (removing the left front tire helps) on your back. By looking up, you will see the point where the rubber fuel lines meet the metal hard lines. Loosen the screws holding the hose clamps on. Then, carefully push the rubber lines from the mounts on the hard lines. NOTE:Gasoline will immediately exit the fuel lines when they are removed, not under pressure, but just what's in the line will drip out. Since you are laying on your back, the most likely path it will take will be into your face and eyes. You do not want this to happen. So either, prepare yourself and shield your face, or wear some kind of eye protection. I never said this job would be fun! Once you have removed the old lines, feed two lengths of the 1 meter (16 12 1 180 409) fuel hose down from above (from the engine compartment). Don't attach the lines in the engine compartment yet as you'll need all the slack for fiddling with mounting them below. Now crawl back under there and then, before you do anything else put the hose clamps back on the ends of the new fuel lines. Next do your best to push/pull the rubber line over the end of the hard line. It's difficult as you must snake your arm up between the suspension arm and the steering tie rod to reach it. It's a tight fit and a pain to get leverage. Once the hoses are pushed down onto the metal hard lines, (I hope you remembered to put the hose clamps on there first!) tighten the hose clamps in place. Up above in the engine compartment, the line going near the firewall will probably have about 6 inches of slack or so which you can cut off once you've determined how much you need. Save that in case you need it later. The other hose going forward towards the fan will probably be the perfect length and not require cutting. It's time for a beer!

This is a picture of the driver's side engine bay. Note the markers pointing to the fuel hoses that will need to be replaced.
This is the view of the line from the tank and the return to the tank line where they meet the chassis hard lines. This view is laying on your back under the drivers side front of the car looking up.

REAR HOSES

Now, you've finished the easy part. Here comes the big fun. The rear hoses consist of a crazy mess of twisting and turning hose connecting the fuel filter and pre-pump to the pump. This bundle of joy is hanging underneath the passenger rear fender. Removal of the wheel is necessary for easy access (unless you want to crawl on your back more than you really have to. In that case, you can leave the wheel on). The other part of this assemblage are the two hoses going from the main pump by the fuel tank (accessed through the trunk) to the fuel filter section.

Beginning with the first part, the fuel filter assembly, lets tackle the fuel filter itself. You will need to remove the hose clamps from the fuel filter on either end, and then remove the large clamps that hold the fuel filter canister to the mount. BEWARE of the orientation of the fuel filter, make sure that you pay attention to which way the fuel filter's directional arrow is pointing. (if its still visible on the side of yours, I had to wipe away alot of dirt to see the arrow on my old one). When you place the new filter in the bracket, ensure that the arrow is pointing in the same direction as the old fuel filter's arrow was. Tighten up the bracket clamps that hold the filter on, but leave the hoses hanging for now as they will be replaced in a moment.

This is the section where it is difficult to gauge whether to use the elbow joint hose (16 12 1 176 821) or instead to use a small piece of the 16 12 1 180 409 hose. If you need a small section of the 16 12 1 180 409 hose, you should have a small length left from the engine compartment hoses that you can use. The reason for all this caution stems from the experience I had doing mine. I used the elbows for all the joints because that is what the parts CD said to use. However, this twisted the apparatus in an unusual way which was different from the manner in which the old hoses had connected. This twisting caused torque on one of the elbow joint lines where it connected to the fuel filter and it popped off while driving and stranded me (I didn't realize how simple the problem was, otherwise I wouldn't have waited 2 hours for a tow truck. I would have crawled under the back of the car and pushed the hose back on the fuel filter.) The other concern with making sure this apparatus is set up properly is that the small section of hardline that kind of hangs in the air suspended by a piece of fuel line on either end (elbows, or small length, whatever they are) comes very close to the driveshaft boot exiting the differential. Having this come into contact with the driveshaft boot at speed is an experience best left to the imagination. So, the procedure here is replace one piece at a time, using an elbow joint hose or a piece of the 16 12 1 180 409 hose, whichever seems to fit best. I took the whole thing out at once and that is why I had difficulty figuring out how it had originally looked. Its best to do it one at a time to keep everything straight.

The final part of the rear hoses will be the most difficult and involve the most swearing. First to access the hoses by the fuel pump, lift up the trunk mat and you will see a black circle with three screws. Remove the screws and the circle and this will grant you access to the top of the fuel pump and the fuel tank. You will see two lines and some wires running to the fuel pump. One line is LARGER than the other. This line is the 16 12 1 176 440 hose. The other hose is our old friend, the 16 12 1 180 409 hose. These hoses disappear to the right and reappear down by the chassis hard lines leading to the pre-pump (over the passenger rear wheel). Along this route, they pass through an extremely small space between the bottom of the trunk and the fuel tank. This is tight enough for the 16 12 1 180 409 hose, but the thicker 16 12 1 176 440 has a tough time fitting through here. One solution that Jim Davis came up with (see picture below) is wrapping the end of the old hose in duct tape that is wrapped around the end of the newer hose and pulling the hose through in that manner. On the day that I did my hoses, it was quite hot so the duct tape was not sticking very well and came off. If this happens, the only way to do this is hope that there is sufficient space to push the hoses through towards the right (towards the fuel filler door almost) and then looking towards the rear of the passenger rear wheel-well, you should see the hose appear. From here, it needs to be snaked through a small opening between the wheel well liner and up towards the hard lines under the car. If you look at the setup for a while before you attempt to remove any of these fuel lines (look at the hard lines and see where the hoses seem to be coming from) it will make sense. It is a bear of a job though and the hoses don't have quite enough strength to maintain their shape when you push on them to get them from the trunk opening to where they need to be to connect to the hard lines. Once you have snaked the hoses through this maze of twists and turns, hook them up to the hard lines as usual (replacing any rusted or worn out hose clamps that you may see). Then cut any excess that you don't need where they meet the fuel pump by the trunk opening, and attach them there. There should be one more small section of the 16 12 1 180 409 up by the hard lines that you'll see. There is a picture of it below. Cut a small section of the hose to fit there and replace that piece. That piece was very cracked and in terrible shape on my car (it is the first picture in the beginning of this FAQ showing the need to replace old fuel hoses).

Crit Taylor adds the following:
I'd like to share some addtions though that I found made the most difficult part a lot easier. The part I'm refering to is where the two hoses go from the top of the gas tank (accessed through the port in the trunk) down to the assembly behind the right rear wheel.

I tried the FAQ's suggestion of using duct tape to bind the old hose to the new and then tried pulling the whole thing through from the top (trunk). Figuring that the duct tape would not be strong enough I even sewed the two hoses together before I taped. This might have worked but I did not realize that the hoses were attached to the frame via a plastic tie that was in the middle and out of sight. In fact the large hose was held by two ties, one easy to spot and one not. So here is addition #1 - look and or feel for the hidden tie and remove it.

I then studied the path that the hoses had to go through and decided I needed at least 1/4" more in order to get them through without too much struggle. So I loosened the four bolts that hold the gas tank in place and let the tank go lower just enough without taking any of the bolts out. This definately made things a lot easier.

Since I had already pulled the old hoses out and did not have them as pull guides, I then took some more duct tape and created long (8" or so) thin extensions on the ends of each of the hoses with the tape. These I found were easy to get through and then I was able to pull on the duct tape and get the hose through without much struggle. — Crit

Congrats, you're done. Make sure the car starts (it may take a few seconds of cranking for the fuel to cycle back through the new lines you've installed).

Access panel in trunk to fuel pump and top of fuel tank.
The hoses connecting to the in-tank fuel pump.
View of fuel filter assembly and hoses.
Fuel hoses coming from in-tank pump over the top of the fuel tank and towards the opening in the wheel well to reach the hard lines.
Looking up at the fuel filter assembly.
View of one of the elbow bend hoses coming from the pre-pump.
Looking up at the small piece of hose connecting two hard lines, near where the hose from the in-tank pump goes to the hard line. This is the piece that was in bad shape on my car.
Another view looking up at the small hose, the 16 12 1 180 409 meeting the hard line, and the large thicker 16 12 1 176 440 hose on its way to the pre-pump.
The duct tape method of pulling the new hose through to the wheel well.
Location of the rear fuel filter assembly.

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