:: Double Fuel Filter Assembly – ’94 530i

[artguy]

There's nothing hard about changing your fuel filter, or filters, but between Bentley and every source I’ve checked on-line, you don’t get much info regarding a Double Fuel Filter Assembly.

So for anyone who’s curious here are some install notes with picts:

A) The Double Filters are located by the right, rear wheel. IIRC, the single filter assembly is located on the left, rear wheel. (Right and left of car is as if you are standing at the trunk looking forward to the front).





B) Remove excess pressure in the fuel system by opening the Filler Cap. Also, pull the fuel pump fuse in the forward fuse box, start and run the car until it stalls. Get a shallow pan ready to have under the filters to catch the fuel that spills. I only lost about 1 cup of fuel, so not much. Fuel is not going to spray out, but it will drain from the filters and the lines attached.

EDIT: Originally I was incorrect about fuel spraying out. The reason my fuel pressure wasn't much was due to the fact my fuel pump had died and I was changing the filters in connection with changing the pump. Typically, on cars with healthy fuel systems, there will be 3-3.5 bar pressure (depending on the regulator) in the system. That's more than enough pressure to give you a face full of gas, as anyone who's been in the business a while will tell you. A common practice is to pull the fuel pump fuse in the forward fuse box, start and run the car until it stalls.

C) The filters are held to the car by a Double Barrel Mounting Bracket. You loosen the filters by turning the Retaining Bolt in the middle of the bracket. IIRC it takes a 10mm socket. You do not need to remove the bolt. I loosened it enough so I could slide the filters back and forth. There is a rubber cushion sleeve that goes over each filter which is then between the filter and the bracket. You will need to remove these rubber sleeves carefully from the old filters and install them on your new filters.



D) I loosened the four hose clamps and then removed the hoses from the side of the filters farthest from the wheel well first. That way I could slide the filters out of the bracket and get a better grip on them to remove the hoses closest to the wheel well. Be careful of the hoses and replace them if they are cracked or damaged in any way.

E) I used new hose clamps (9/16”-5/8” size) which were rated for high pressure fuel injection lines. Overkill…maybe, but I didn’t want the cheap ones which become oblong and pinched rather than remain circular when tightened. If the clamps don’t tighten evenly they can cut the hoses.

F) Installation of the new filters is simple…just reverse the steps above. NOTE: Remember to install the new filters with the arrows pointing in the proper direction for the fuel flow. (Flow is from right side of car to the left).

Hope it helps somebody.

[Ross]

One pump, one line, two filters in a paralell configuration. WTF is that all about? Sometimes BM engineering just pisses me off.
I've bought ONE filter for mine and intend to abandon the second one... F 'em!

[Fred/Houston]

I was driving my 94" 540i and smelled really strong gas. When I stopped to check I noticed the underside of the car dripping gas right where those fuel filters are.
I bought replacements but they were shorter than the originals, so I swapped them out for the exact same ones. I changed the lines 1st and the dripping stopped and will be changing the filters in a matter of days, so good timing with your write up and thanks!
Fred/Houston

[artguy]

I was incorrect regarding the fuel possibly spraying out due to pressure.

My fuel pump had died and I was replacing the filters in connection with replacing the pump. So my dying pump de-pressurized my system as if I had pulled the fuel pump fuse in the forward fuse box, and run the car until it stalled.

I edited the procedure above.