Philes' Forum by Vic Lucariello

Hello, Bimmerphiles! I apologize for being absent from this august journal for a couple of months, but some driver school tech issues and, unfortunately, some work-related stuff have kept me from spending any quality time with the ol' keyb oard.

Sometime ago, I wrote about a BMWNA 'Service Action' pertaining to underhood fue l hoses. Judging from the condition of the fuel hoses we see at driver school t ech, it seems appropriate to rerun the item. [As I understand it, a service act ion differs from a recall in that a recall is intended to correct a defect, whil e a service action, to use BMWNA's words, "allows customers to benefit from tech nolgical improvements that are incorporated as running production changes".]

Most fuel injected Bimmers use metal tubes to convey fuel to and from the engine compartment. The "from" refers to the fuel return line which is required for t he fuel pressure regulator. Flexible 'rubber' hoses connect the metal tubes to the engine. These hoses (specifically, the return hose) are the subject of the service action. If anyone out there can explain to me why the supply hose is no t affected, I'd appreciate it! The only possibility that makes sense to me is t hat the supply hose, which carries fuel from the tank, may operate at a lower te mperature. BMW has come up with a different hose material which "has an optimiz ed composition which improves resistance to the various types of additives used in todays fuels". I suspect the new material is more compatible with the oxygen ated fuels we have come to know and love.

BMWNA has a hose kit for each affected vehicle. The kit consists of the appropr iate length(s) of hose, and a new type of hose clamp whose drive hex shears when the correct tightening torque is reached. My recommendation is that all the und erhood fuel hoses be replaced, not just the return hose. I believe the kits add ress the return hoses only, so be sure to obtain enough hose and clamps for the supply line as well. An extra 3 ft. [1 meter] of hose and two additional clamps should suffice for most Bimmers.

Which vehicles are affected? Good question. Certainly some E-30 cars ('84-92 3 -Series), E-28s ('82-88 5-Series), and E-34s ('89> 5-Series). To find out for s ure about a particular vehicle, call a BMW dealer and ask him/her to run your VI N in the computer. As it was recently explained to me, any dealer should be abl e to tell you of any recalls or service actions which have yet to be done on you r bimmer. If you experience difficulty, call me with your VIN and I'll try my d ealer contact, who is extremely helpful.

Even if your Bimmer is not subject to the fuel hose service action, I recommend that your take a close look at your underhood fuel hoses. If they exhibit any c racks, abrasion, and/or fuel seepage, by all means replace them. [Sometimes the supply hose connections seep fuel only when the car is cold] If they are more than about 7 years old, replace them whether they need it or not. The fuel pre ssure in these hoses gets up to about 45 psig under full-throttle conditions, s o why take a chance? If you are unsure of what to look for, just bring your car to a monthly meeting and I'll be glad to show you.

Some cars came equipped with pulsation dampeners in the fuel supply hoses. Thes e dampeners are made of metal and are disc-shaped; about 2 in. [51 mm] diameter and about 1 in. thick. I recall that BMW had problems with these underhood damp eners leaking fuel and replaced them with short lengths of tubing. If your car has either the dampeners or the tubing replacements, you can eliminate them when you change the hoses.

Although replacing the hoses and dampeners is a simple task, please keep the fol lowing in mind when doing the job:

1. Before you begin, be sure to de-pressurize the fuel system by cranking the en gine for 10 seconds or so with the fuel pump fuse removed.
2. Work in a well ventilated area, as some gasoline will be spilled. Do not do the job in your attached garage!
3. Be sure that the engine is cold, and disconnect the negative battery terminal .
4. Wear eye protection and have your fire extinguisher handy.
5. You will need to raise the front of the car and support it on jack stands or ramps.

The brake drums and rotors of Bimmers newer than 2002s are retained by an 8 mm, internal hex bolt ("inner hex bolt" - Part No. 34-11-1-123-072). Removing these suckers can be a real bear, especially if they've been in place for awhile or i f someone has previously overtightened them or butchered the 5 mm internal hex.

Here are some things to try if you experience difficulty in removing an "inner h ex bolt":

1. Hit it with some penetrating oil and let it sit for awhile.
2. Use a nail or other suitable object to clean out the internal hex. You'll be surprised at how much better the hex wrench will work if you do this.
3. If the 5 mm internal hex is butchered, try using a 7/32" hex wrench and tappi ng it into place with a hammer. The tapping action will help to loosen corrosio n. Moreover, a 7/32" wrench measures 5.6 mm and sometimes does the trick.
4. If you have access to an impact driver, use it. An impact driver is a hand-h eld device with a square drive on one end which accepts sockets, hex wrenches, etc. Striking the driver with a hammer imparts a torque impact to the drive end. This works very well to loosen rusted fasteners, without shearing them as woul d a powerful pneumatic impact wrench.

Be sure to use a bit of anti-seize compound when you reinstall the inner hex bol ts, and don't overtorque them. 120 lb-in (Uh, Ross.....that's lb-in, not lb-ft; For you technoids....that's 13.6 Newton-Meters; And finally, for Al Drugos..... that's not very tight, Big Al.) should be plenty. I suggest that you keep a cou ple of these bolts in your toolbox and use them to replace any you come across w hose internal hexes are even slightly butchered.

Upcoming Philes' Forums will feature material from two of our Lime Rock Driver S chool hotshoes, Warren Brown and Dave Hellman. As I have previously mentioned, Warren replaced the notorious Profile Gasket on is 318is and Dave has installed a suspension kit in his. Both drivers were kind enough to write up their experi ences to share with us. Actually, this month's Forum was supposed to have Warre n's write-up, but technical difficulties [Our word processors don't seem to like each other] precluded it.

Anyone wishing to contribute to Philes' Forum should contact me via the info on the masthead. I'm interested in tech tips, repair/maintenance questions and/or tips, dealer horror stories, product evaluations, etc. Please call before 8 PM , and if you leave a message, PLEASE INCLUDE YOUR WORK PHONE NUMBER. Also, plea se be patient, I try to return every phone call, but it sometimes takes awhile. The best way to contact me is via e-mail.

Copyright 1997 - V. M. Luca riello, PE