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Seat Looseness

44522 Views 107 Replies 37 Participants Last post by  rorz12
I couldn't find the original thread on this subject, so forgive me for starting over. (Maybe it was the other forum.) I finally got around to looking under the seat and this is the letter I wrote to BMW. I'll let you know if and when I here back.

There's a second issue I didn't mention, but I didn't want to muddy the waters. I also found that the thigh support can move a little if it's positioned anywhere other than full in.


I would like to bring to your attention an issue with the 6 Series front seats that seems to be common amongst many owners based on the forums that I read.

Simply put the front seats have a looseness that allows movement under load when the car is cornering. It does not take much lateral input to generate movement.

I have investigated this problem to isolate the cause. I am an engineer with 30 years automotive experience, so please take my analysis seriously and forward it to the appropriate personnel.

There is a cross-car steel support tube that passes through two (I assume urethane) bushings under the forward edge of the seat frame. This assembly is part of the mechanism used to raise and lower the front edge of the seat cushion. The bushings, attached to the seat cushion pan, are oblong in relation to the diameter of the tube to allow longitudinal movement as the mechanism is raised and lowered. Lateral movement is controlled by flared "stop" features on the steel tube on either side of the outside (driver) bushing. It is the relationship between the sides of this bushing and these stop features that is problematic.

If the front seat edge is adjusted to any position other than full stop (high or low), which places the tube firmly against the bushing, lateral movement can occur between the sides of the bushing and the flares on the tube. This motion is easily felt by the seat occupant as the bushing (and seat) bounce back and forth between the two stops on the tube. Hardly acceptable on this class of automobile.

Many 6 Series owners have taken their cars to the dealership with no resolution. A permanent solution needs to be driven from the top down. It seems a simple solution would be a wider, harder lubricious bushing to prevent the unwanted lateral movement without binding the adjustment mechanism. But I will leave that analysis the the BMW engineering staff.

Thank you for your attention to this important matter. I look forward to a solution and positive response.

Feel free to contact me at any time to discuss this further.

Best regards,
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Could we get an update on the success of Allan Thompson***8217;s bracket. Either from Allan or others that have tried it. Has it worked for the long haul? Us ***8220;out of warranty***8221; guys would prefer this to paying the dealership for a new seat pan.
Thanks 640ijims, are you implying that flopping the seat back into position causes the problem?
Not sure what that means. The simplest solution??
Well with my coupe I very seldom even move the seat back forward to allow passengers in the back seat. I have done that maybe 4 times in the years I have owned the car. So I don***8217;t think that***8217;s the cause of the dreaded seat thump in my case. The car does not see the snow much, but has proven to be very good the few times she***8217;s been out in it.
Hey RORZ, I posted a fix 2 yrs ago, maybe you missed it. It’s been 2 yrs and NO thump when I turn corners. The only compromise is I do heard a click when adjusting the seat, like giving rear seat passengers access to get on. It isn’t a problem because I am the only driver and the seat stays in one position most all the time. Here’s the link to my post, complete with pictures. Good luck!
Thanks! I hadn't come across your post so thanks for sharing. As a matter of fact, I was thinking of doing the exact same thing with zip ties! I was thinking of placing them in the groove itself, wedged between the bushing and the flared part of the rod, but maybe there isn't enough space realistically. I'd really prefer not taking the seat out so hopefully I can slot those zip ties in with the seat still bolted?!
The seat isn’t that hard to remove. It is heavy, but I did it alone and I’m an old fart ( 70 at the time). An assistant would make it easier. Good luck
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