Passenger seat won't recline - gearbox removal

[CastleAlver]

Looking at the 'passenger seat won't recline thread' https://z4-forum.com/forum/viewtopic.php?t=65853&start=15 there was no further info on disassembly, and I've got the same problem. Does anyone know how to get the recline gearbox out?

I've got the seat out, side trim panel off and other parts out the way, and removed the motor - but I can't see how to physically get the gearbox out. **UPDATE** detailed added in thread, to explain the solution.



I've removed the two torx bolts holding the gearbox to the seat frame, but it's still held in position with the tube. Releasing the small circlip at the other end of the tube doesn't seem to help either.

For info, to remove the side trim panel it's one torx screw, then unclip the visible lower clips, and release the two hidden upper clips with a flat blade screwdriver (access through the inside of the trim via the bottom edge you've just unclipped).

Then you can remove 4 torx screws (one smaller tucked inside) to release the plastic piece behind the switches , which is covering the screws to the motor gearbox.

Two screws holding the gearbox to the frame removed, now it can move it slightly, but can't see how to physically remove it from the seat base frame! Any ideas or suggestions welcome!?

 

[CastleAlver]

Update - it’s out !

The frame has a bit a of flex, so levering between the metal gearbox front , and the seat frame enables just enough clearance to encourage it out, up and slide off the tube. Turns out it’s just the large plastic cog in the gearbox missing a few teeth. I don’t have much optimism in finding the actual replacement part , so probably will be a replacement gearbox and motor complete.

 

[CastleAlver]

I remembered I had a different seat motor, which was bought in error thinking it was the reclining part (£14 eBay). Left Seat Angle Adjustment 52107111877
I decided to strip this down to see if it’s the same gear wheel (this was mentioned on the other thread) - success!! It’s same part.

For reference, this was a tilt/ height adjust seat motor/gearbox which is much easier to get hold of than the reclining part.

The other one I bought on eBay:


Repairing my broken recline gearbox:

Cover removed,


Old broken gear


New plastic gear going in



Fixed, ready to reassemble into the seat

 

[SW_Coupe]

Hey - exact same problem! Are you able to explain in more detail how you removed the gearbox?

I can get all of the trim off, but am stuck from that point - with no obvious way to release the tension holding everything in place.

Thank you for your follow up thread!

 

[CastleAlver]

Hi, Really sorry - I've only just seen this! You've probably got it sorted by now, but here's some detail for the next person:

There is some flex in the seat frame (when enough force is applied). The gearbox can be removed by using a suitable lever between the metal face of the gearbox and the seat frame - but it's tight, and a fair amount of force is required. Once you've created enough space, the gearbox can be easily removed. The frame will spring back, so similar force is required to re-install and to finish off, apply some additional leverage/force on the other side of the frame to ensure it's back in the same position and clamped up nicely.

 

[SW_Coupe]

Amazing! I actually haven’t fixed yet, and really appreciate your reply.

Sounds like lots of force is required - we didn’t push too hard, but will try this and see. Had wondered if you had further disassembled the seat, so your reply is helpful for confirming that you had not.

I do wonder if there is less leverage possible due to the recline position that my seat failed in - fully reclined - but will revisit and confirm.

Thanks again for picking this up from the dead!

 

[CastleAlver]

Glad it's been useful. I'd suggest using a decent size lever or two (at least 18") and ask someone to hold the seat down, to stop it moving whilst you start applying force. Hope you get it sorted.

 

[tinted184]

I've just done this exact same repair on my own car so thanks for the tips. The gearbox was extremely difficult to remove and although I was able to get some leverage on the frame I manage to snap part of the external motor shaft which is ultimately how I removed it. Fortunately I found a replacement gearbox (complete with shaft) from another car on ebay. It was listed as "BMW E53 X5 SERIES OEM FRONT LEFT SIDE SEAT ADJUSTMENT ACTUATOR MOTOR 8251615" and looked like an exact match in the photos and it was! I swapped out the gearbox keeping the old motor and used the new motor shaft to recouple the two shafts. Putting it back in was an absolute pain as you need to make sure the seat incline is the same on both sides of the seat and it also needed to be pulled into a more upright position before engaging with the motor shaft. I ended up removing and replacing the whole mechanism numerous times to get this right, not helped by the fact that by this point the seat frame was now warped. Many many hours later and its fully working again so I'm pretty chuffed but this is not for the faint hearted! Thanks again for everyone's tips, they definitely helped!

 

[MikeyH]

Amazing how incredibly inventive forum members are on here

 

[platinum]

Working on the same problem now. From the above it looks like you can get the parts needed from either of these to other parts?

BMW E53 X5 SERIES OEM FRONT LEFT SIDE SEAT ADJUSTMENT ACTUATOR MOTOR 8251615
or
Left Seat Angle Adjustment 52107111877

Is there a part number for what is actually broken or is taking parts from one of the above the only way?