UPDATE: Seat slide twist issue [SOLVED]

[Kkuba]

Hello folks,

I have just developed an issue with the passenger's seat of my 2008 135i.

It appears as though it has developed a twist due to a malfunction of the electric slide adjustment.

I have search a lot on the web, and found a lot of information on seat twist of the seatback, and some on the seat height/tilt, but only one thread on seat slide, that did not provide a resolution.

The seat was being operated by someone else, so I did not witness it, but I'm told it was being slid forward, and then one side stopped moving.

The seat then became bound. The motor would engage, wouldn't move (as if at end of travel), and disengage, in either direction.

I was able to unbind it, by unscrewing the seat from the front scissor lift mechanism. This then allowed the slide motor to run normally again. Forward and backward, as normal.

But now the rails are still crooked, one is further forward of the other, as if the gear skipped a number of teeth on one side, then re-engaged.

I have the seat out of the car, but not sure what to do next. There is a support bar that holds the motor, but at the moment I am unable to remove it, as I don't have the correct torx. It seems to be somewhere between 40 and 45. My first question, does anyone know what size this torx is, as all tool shops don't stock any like that, and need to order it in, so I need to know which one to order.

Wide

Motor member

Close up of torx that I want to remove and hopefully see inside.

Secondly, I'm not even sure what I will see under there, if anything. I'm hoping that the gear mechanism will be visible and easily manipulated, but it doesn't look like there will be any access under there.

Additionally, the motor was unseated form its mount when I started inspecting. The black thing immediately under the plug in the last image is soft rubber, and had two 'feet' had slipped out of the metal tabs.

This may have been the cause of the issue initially, but I have seated it again, and we are still stuck several teeth forward on one side.

Any suggestions welcome.

UPDATE: Seat is now fixed. Updating for others incase they have the same issue. What I did not know at the time was that there was something stuck under the seat while it was being moved. So to fix it, all I did was pull on the cable that reaches to the rail from the motor which turns the gear to move the rail, this can be seen in the third image poking out of the motor directly beneath the blue and yellow wires. This allowed the gear to disengage and skip teeth. At this point I operated the motor and slid the other seat rail forward to align it with the other one, while maintaining tension on the cable. As soon as the cable was released the gear re-engaged and the seat worked normally.

Thanks to all those that provided suggestions.

[JBT2]

Does this thread offer any clues? Looks like one of the drive cables can easily break. It also seems you can (easily?) pull the sheathed section of the cable out of the track/rail. If it can be disengaged like that, you might be able to re-align the tracks.
https://www.e90post.com/forums/showthread.php?t=252729

[Kkuba]

Thanks for your response.

I did see that thread, I tried to pull on the cable that come out of one side, the same side as in the picture I attached, and I managed to pull some slack (the cable bowed a fair bit) but it I felt if I kept pulling I would kink the cable as it is quite short and the angle is akward.

Maybe I will try it again.

[JBT2]

Hmmm...it's difficult to figure out without seeing the assembly. Maybe your first idea of removing the two torx screws might be best. At least it "looks like" you might be able to jiggle the motor and drive cable(s) out of the track(s) to get them re-aligned.
Can you take a plasticine impression of the torx bolt head to determine what size torx driver you need?

[RadiuM]

If you have a 1/4" / 3/8" socket set, id recommend getting a set of these.

https://www.kincrome.com.au/torx-set-tamperproof-11pce

From memory they were about $30 from Bunnings, and along with a set of e-torx you can pretty much undo almost everything on the car.

[JBT2]

..and these https://www.supercheapauto.com.au/p/...=en_AU&start=6

[RadiuM]

Derp, how could I forget the hex key!

[Kkuba]

Originally Posted by JBT2

Hmmm...it's difficult to figure out without seeing the assembly. Maybe your first idea of removing the two torx screws might be best. At least it "looks like" you might be able to jiggle the motor and drive cable(s) out of the track(s) to get them re-aligned.
Can you take a plasticine impression of the torx bolt head to determine what size torx driver you need?

I agree, I think removing those torx is the correct way forward.

The tool shop I called suggested I take measurements of the head itself, and bring those in. I tried taking some measurements, but I'm a bit sceptical of this, as when I took some measurements with a vernier caliper, I got different readings every time. As it depends on how deep you insert it, which 'gap' you are measuring (between which teeth). The differences in this dimension are so minuscule at this scale, it feels like a fruitless effort.

I checked against a dimensions chart for torx bits, but I could only find a chart with increments of 5 in that range, and so some measurements I took were just a bit larger than a T40, others a bit smaller than a T45, so it didn't really help me narrow down which one I need.

I considered calling BMW and asking what they would use, but I'm fairly certain that this is not a serviceable part, as the entire seat rail is sold as one assembly. And so they would probably not even touch it.

Originally Posted by RadiuM

If you have a 1/4" / 3/8" socket set, id recommend getting a set of these.

https://www.kincrome.com.au/torx-set-tamperproof-11pce

From memory they were about $30 from Bunnings, and along with a set of e-torx you can pretty much undo almost everything on the car.

Thanks for the suggestion, but I already have all of those sizes of torx, and none of them fit correctly.

The T40 fits very loosely, and I have been tempted to give it a go, but it feels like it is fastened very tight, and with so little engagement with the teeth of the T40, I am worried I will strip the screw, then I will be screwed. So I've resisted the urge to push on it any more than I have already.

I never thought it would be so challenging to find the right tool for the job.

The only other thing I am thinking is trying to find another T45, in case this one I have has a manufacturing defect, and is oversized.

[Kkuba]

Seat is fixed, explanation has been added to the end of OP.

Thanks to all those that helped!

[JBT2]

Great result!!
Please confirm which way you pulled on that cable - towards the motor or away from it.

[Kkuba]

Originally Posted by JBT2

Great result!!
Please confirm which way you pulled on that cable - towards the motor or away from it.

The cable is quite stiff and rigid, so the only way you can pull it is hook your finger around it and pull it so it bows, like you would hook your finger around and pull on a belt loop. This then gave the effect of pulling the cable out of the rail slightly, towards the motor.

Happy days.