If you’re an owner of a BMW E39 5-series between the years or 1997-2003 then odds are you may experience or have experienced what is known as seat twisting when trying to recline or raise the back of your seat. There’s probably many other BMW’s that experience this issue but the following fix is done on a ’99 BMW 540i some some steps may differ if you have another model or year BMW.
This rather annoying occurrence means you either leave your seat reclined in one position for the rest of its life or fix it! Which isn’t that difficult and aside from a few supplies it’s doesn’t cost you anything but time.
The reason the twisting occurs is that the back of the seat’s left and ride side are independently controlled through cable operated electric motors and almost always one side cable fails not both hence the awkward twisting of the seat.
What you see in the photo above is the culprit of all our troubles. It’s the cable that operates the recline/raise function and over time the plastic shielding around it ages and expands which causes the cable to retract out of the electric motor that spins it. Thankfully, the fix can be done by any novice DIY mechanic.
Start be removing the twisting seat from the car. There are four bolts holding it to the floor and an electrical harness that you have to disconnect before it’s free.
Once it’s out of the car, flip it upside down and this is what you’ll be looking at.
Pro-tip: If you’re working on the passenger side seat, it has an additional cable attached to it that you’ll need to pop off and before the seat can come out. After you removed all the bolt, tilt the seat up which will give you easy access to it.
Look at the front of the seat base, we’ll need to get access to the electric motors but there’s no real way to get at them without lifting the metal base of the seat up and away.
Using a torx bit remove both bolts that hold the metal base to the seat.
There are two tension springs that are a bit of a pain to get at but using vice grips and a lot of determination they’ll eventually unhook.
Remove the plastic trim that runs around the base of the seat. If you’re lucky like me you’ll find coffee stains and many stray strands of hair.
At this point, the base of the seat should swing up with relative ease. Place a block or similar object to hold it up. You’ll notice that I have already unplugged the connectors from the electric motors. If you haven’t done so yet now is a good time.
We got great access to the motors now but the battle isn’t over yet.