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Monday, June 24, 2024

Doug's Domain

Doug Vetter, ATP/CFI

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Saturday, August 6, 2016

Front Seat Prep

I dropped by the dealer to chat with my technician to get a refresher course on removal of the front seats. I told him my plan -- to remove the seats from the car outside of my garage and then drive the car into the garage where it will wait until the seats have been rebuilt. I suggested that I'd probably just throw a milk crate in the car as an impromptu seat but he suggested I could just sit on the floor and I'd have sufficient visibility over the hood. Apparently the techs do this all the time.

We then discussed the procedure to remove the electric seats:

  1. Remove the headrest. This is needed to allow clearance through the door opening.

  2. Move the backrest to a "normal" position -- not excessively reclined, nor fully upright.

  3. Move the seat forward to expose the rear mounting bolts and remove them.

  4. Move the seat rearward to expose the front mounting bolts and remove them.

  5. Move the seat to the middle of is travel range and then gently tip it backward.

  6. Disarm the seatbelt pretensioner by turning the actuator until the indicator turns from green (armed) to red (disarmed).

  7. Disconnect all wiring.

  8. Put a heavy cloth or padding over the door sill.

  9. Open the door fully and extract the seat from the vehicle.

It should be noted that according to the diagrams we examined the electrical connectors should all be keyed and different types with the exception of those that power the seat heating elements. The connectors for the backrest and base elements are identical but fortunately can be installed in any order. As far as the car's seat heating control system is concerned the elements are the same.

To wrap things up I asked whether there would be any problem starting the vehicle with the seats removed. As I surmised, he said the only result was likely to be an SRS annunciation due to the missing seatbelt tensioners and possibly the passenger side occupancy mat, but the car would otherwise run. Good news. Of course SRS errors are persistent so I'll need to bring the car to him to clear the code but I was planning to do that anyway to show him the finished restoration and the end result of his valued assistance over the years.

A Few More Parts

The other reason I went to the dealer was to swing by the parts department to grab another package of 100 hog rings. I wasted more than planned doing the rear seats and didn't want to come up short while doing the front seats. Those were in stock because apparently the techniques BMW uses to attach seat covers hasn't changed -- even the new cars use hog rings. I was pleasantly surprised to hear this, thinking BMW might have chosen to reinvented the wheel, or worse -- use some kind of glue instead.

With the cringe-worthy rear seat belt plastic cover repair still fresh in my mind I half-heartedly asked if if the plastic covers were still available. I conceded that I could accept a color different than beige, as I knew in a pinch I could paint the part as needed, but that turned out to be unnecessary -- not only was the part still available, I could get it in beige! It took me all of about two milliseconds to decide to order two when he informed me of the very reasonable price. I hate how this part is basically designed to fail, but considering that they were broken, as well as a bit scuffed up cosmetically, before I ever touched the backrests I'm happy that I will be able to replace them. On the other hand, dealing with all that epoxy is unlikely to be fun.

With this success I decided to push my luck and ask if the rear seat belt receptacles were available. These are the parts that accept the shoulder belts and are recessed into the seats near each bolster. Call me obsessive, but I have never liked the fact that the bright red plastic tabs had faded over years of exposure to sunlight, so I figured I'd replace them if they were still available and for a reasonable price. Amazingly, I struck gold on these as well so they are on the way.

I'd noted some time ago that the webbing on the driver's side front seat belt had started to fray, much as it had while the car was under warranty and it was replaced at no cost. There are plenty of aftermarket companies that can re-web these things so I had options in case the part was no longer available but I was again pleasantly surprised to hear that they were in stock so I placed an order. While the part can be replaced reasonably easily with the seat in place the job is definitely easier with the seat removed, so this will be the best time to tackle it.

To wrap up my spending spree I asked whether the receptacles for the front seats could be replaced. I had two goals here: first to match the cosmetics of the new rear receptacles, and second, the somewhat more legitimate need to replace the receptacle on the driver's side after tens of thousands of operations. It turns out that the receptacles are not sold separately and the only way to get them is to buy the entire pyrotechnic seat belt pretensioner assembly. While they are not particularly expensive in the grand scheme of things, they are priced above my impulse-buy threshold so after learning BMW had near 100 each left/right in stock I decided to delay purchase of these units until I have the seats apart. One thing is sure -- replacement of these units requires removal of the seats -- something I'd rather not have to do ever again, so I will probably take this opportunity to replace them.

Up Next

The goal is to remove the seats tomorrow and begin disassembly next week, at which point I have made arrangements with GAHH to ship back the two front seat bases as well as one of my covers to serve as a pattern. This will allow them to rework the strip of leather that joins the seat base and thigh rest covers. I'm expecting a turn of about a week at most, but it will take me at least that much time to repair the foam, prep and paint the bases, inspect the frame for cracks, and install the backrest covers.

Update: 8/7/2016

I managed to remove the seats. I found two 16mm nuts in the front and two 16mm bolts in the rear of each seat. Clearance near the inside rear bolt did not permit use of a socket so I instead leveraged a 12 point box end wrench.

It appears that my seats are equipped with a newer version of the seatbelt pretensioner that lacks the often referenced green/red indicator so I was not able to disable the units, assuming it's even possible or necessary. I plan to contact my technician to figure out what to do with these units so I can begin work.

Feel free to check out the video tour of the front seat.

Mileage: 264000