Like many Z3 owners, my seat belt guides cracked and fell apart. I bought mine with both of these broken, thinking "No big deal, how much can a little part like that cost?". Well, I was right, they are pretty cheap. Unfortunately, they are cost a lot of time and energy on top of that.

After a week or two of seeing these eye sores every time I got in the car, and having to fish the seat belt out from behind the seat, I decided it was time to make them right.

Required tools:

13mm socket
16mm socket
16mm combination wrench
Large slotted screwdriver
Small slotted screwdriver
Needle-nose pliers
Diagonal cutters
Large towel(s)

I. Remove the seat(s) that need to be worked on
Removing the seat is not difficult, but can be a lot easier with a second set of hands to help you lift it out.

WARNING: Do not put the key into the ignition with either of the 2 seats out of the car. If the airbag sensor connectors are disconnected when the ignition is turned on, the airbag light with come on. This cannot be reset without an airbag reset tool. The dealer will rake you over the coals for this (~$70, I think).

A. Cover the door sill, center console, and anything else that you might bump into with large towels. This will help prevent collateral damage to your interior while you are wrestling the seat out of the car.
B. Slide the seat back to expose the two nuts on the studs holding the front of the seat bracket.
C. Using a 13mm socket, loosen and remove the nuts.
D. Slide the seat all the way forward and fold the seat back forward.
E. Using a 16mm socket, loosen and remove the two rear bolts.
F. Using a 16mm combination wrench, remove the seat belt from it's mount on the seat.
G. Disconnect the wiring harness under the seat. There are 4-5 connectors per seat. The driver side is the easiest of the two, as the seat heater connectors are in the rear and fairly easy to get to. The passenger seat is another story. The heater connectors are deep under the seat. Take your time with all of the connectors and never pull them apart by pulling on the wires. It helps to tip the seat forward while disconnecting. I was able to tip the seat forward by wedging my shoulders between the seat and the carpet behind it while I was disconnecting.
H. This is where an extra set of hands comes in handy. Carefully lift the seat off of the front studs and out of the car. I found it to be easiest to do this with the seat back fully reclined. This can be done solo in a pinch. I personally did it by myself, and I am not all that strong. Take your time. It is very easy to scratch things with the seat brackets while removing the seat (hence the towels ).
I. Take the seat someplace where you can lay the seat out without damaging the leather (carpet works well).


II. Disassemble the seat
This is the part where you realize why BMW charges $200+ per seat to replace the seat belt guide.

A. Remove the two plastic plugs at the bottom of the rear plastic shell. You can either pry them out from the top with a slotted screwdriver, or slide the screwdriver behind the plastic shell, next to the plugs, and twist the screwdriver so that it pushes the plug out. This method results in MUCH less damage to the area around the plug. I figured this out after the first one .

*Note the electrical connections in the bottom center. This is where they are on the driver seat.



With any luck, your plug won't be too banged up.



B. With the plugs removed, lay the seat down on its front. Lift the bottom of the plastic shell and pull it towards the top of the seat. I wrapped a thick towel around the bottom edge of the shell and gave it a couple taps with a rubber mallet to get it loose. There are plastic hooks on the shell (circled) that snap onto the seat (circled). Once the hooks slide free, remove the shell and set it aside. The nylon portion of the seat skin is now exposed.



Before you can unzip the seat cover, you will need to remove the yellow sensor. Be VERY careful with this sensor, as it is not very sturdy and could be easily damaged. There are two funky-looking expanding plugs holding the sensor onto the seat frame.



C. Using a small screwdriver, push the black center portion in towards the seat. Don't worry about it popping out the back of the plug, as it will just fall to the floor.



Once the center is popped out, just wiggle the plug out of the seat.



D. Using diagonal cutters, clip the zip-tie holding the sensor wire to the seat frame.



E. Unhook the bottom of the seat back skin by finding the plastic channel at the bottom of the seat back where the front of the seat hooks together with the back.



You can unhook the two sides by reaching under the plastic channel and rolling the plastic strip downwards and out of the channel.



F. With the channel unhooked, you can now unzip the back. Needle nose pliers help if you have a hard time with the zipper.


G. Unhook the leather straps around the lower seat frame cross brace. These are just tucked behind the brace, so just wiggle them free.





H. Push the plastic channel and leather tabs through the crack in the seat.



I. Begin pulling the seat skin up off the bolsters to reveal more of the back.



J. Unhook the nylon straps along the frame of the seat. These straps are stitched in to the vertical seams of the front of the seat. When the straps are pulled tight and attached to the frame, they hold the seat skin in the right shape.



Each strap is held to the frame by a "hog ring". You can open these rings up by forcing a screwdriver into the overlapping part and twisting it open. Needle nose pliers help turn the run on the frame so you can get the strap loose. I believe there are 5 of these rings per side of the seat. Make sure you don't damage the straps, as the seat will look like crap if you can't hook them back to the frame when you're done.



Here is where I ran into serious problems. The bottom strap is hooked to the frame behind the crossmember where the yellow sensor was mounted. I couldn't reach these rings, so I couldn't pull the cover up all the way. Because of this, I had to do the rest of the operation by sliding my arms up the skin and working blind. This is the worst possible way to do it, and my hands were screwed up for a couple days after. I will continue the how-to assuming that I had been able to get those straps loose and do everything right.

Get all of the straps free of the seat frame and pull the seat skin off of the seat.