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Saturday, October 19, 2019

Doug's Domain

Doug Vetter, ATP/CFI

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Tuesday, April 7, 2015

Passenger Airbag Recall

Last fall I received notice of a campaign that affected the E46's passenger airbag. The gist of the issue was that the airbag gas generator was overcharged during manufacturing and might cause the metal case of the generator to explode during actuation in a crash. The effect would send shrapnel everywhere, potentially injuring vehicle occupants.

When my technician pointed out there was no time limit on the recall I decided to postpone the work until a more convenient time -- now. Although after discussing the scope of the job with my technician I knew I could tackle it myself that would have made no sense because both labor and materials were covered and I knew the car would be with my technician for other reasons. So today a defective nine year old airbag was replaced with a new part worth almost $1K retail.

When I was 15 years old I was a passenger in my brother's barely-one-year-old car when an idiot came over a rise at well in excess of the speed limit and half way into our lane on the narrow street. We hit nearly head on, and not only were there no airbags in the cars of this era, I wasn't wearing my seatbelt. The collapsible steering wheel helped decelerate my brother more slowly so he walked away without a scratch. I wasn't so lucky, and still bear a scar on my forehead to this day.

For this reason I have always seen the value in airbags, but I sometimes wonder about the long term cost of supporting cars equipped with them. This one was free. The other airbags won't be, and assuming I still own the car in another ten years I wonder if they will even be available for purchase at any cost. This is one of the reasons why I think a couple of airbags up front are a good idea but any more than that are a long term liability that few people fully appreciate.

Pilot Super Sport Installed

(Image: E46 after installation of summer rubber)Last fall I found a small bubble in the sidewall of one of the original Bridgestone runflats. That and the fact that the tires were near the treadwear indicators was enough to convince me that the tires needed to be replaced so I ordered a set of the best street tires on the market -- the Michelin Pilot Super Sport. As usual Tire Rack drop shipped to my dealer where my technician of 17 years installed them today.

I've driven the E46 less than 20K miles over 9 years and figured out some time ago that the suspension was good, but not perfect. And now I know why. Leaving the dealer for the trip home I was struck by how much better the car felt with non-runflat tires. The conditions did not permit a full exploration of the performance envelope but off the bat I could feel the skittishness I'd long associated with the ZHP over bumps in the pavement was completely gone. The ride was better, and the steering even more crisp and sure-footed than usual.

Today during vehicle development suspensions are tuned along with the tires to produce the desired performance. That was not the case back in 2006 when, nearing the end of the model run, BMW saw fit to equip the E46 with runflat tires. The end result was less than ideal suspension tuning. With the installation of regular tires I have corrected that mistake, and I'm looking forward to exploring my "new" E46 in the coming months.

Full Size Spare Issue

While installing new tires I decided to move to a full size spare to replace the crummy space saver that is limited to 50MPH. Some earlier tests with some spare ZHP wheels I had on hand demonstrated quite clearly that the rear wheel (8.5") would not fit but the front wheel (8.0") should. However, these wheels did not have tires mounted to them and it's well known that the Michelin PSS are wider than their official section width might otherwise suggest. So I wasn't exactly surprised when I put the new spare in the trunk and realized I could not secure it because the retaining stud was too short and the spare tire cover sat about 1/2" proud of its proper, level position simply due to the excessive width of the wheel and tire.

The rusty, cobweb-infused gears in my head reluctantly started moving. I could fix this by installing a taller mounting stud or by machining a deeper retaining cup so the wingnut can grab the threads on the existing stud. It's not clear whether the threaded stud is actually a bolt and whether it's press-fit or threaded into the body. If it's threaded and I can remove it easily enough I'll install a longer stud and reuse the factory retaining cup. Otherwise I'll have to manufacture a new cup.

Even if I address the retaining bolt issue there is still the minor problem of the spare tire cover not sitting level. The factory cover actually consists of two pieces -- a hard fiberboard piece and a flexible rubber-backed carpet. Ideally I'd create a new raised aluminum panel to replace the fiberboard component so the carpet sits level, but it's not really a big deal. The entire trunk is usable as is.

Mileage: 19284