991 DIY: Removing / Installing Front 3-Point Seat Belts

Following is a brief DIY for those of you out there who want to swap their factory three-point seat belts for different color, need to remove the seat belts for another project, replacement after an accident, etc.  I don't have any pictures at this time, sorry.  This will have to be purely a description DIY until I can find some time to do this on my own C4S.

Let's go!

Preparation:

• You will need to have an assortment of Hex and Torx bits, sockets and a screwdriver available.  I don't have all of the individual sizes available at the moment.
• Have a set of plastic interior trim tools handy.  You will need to remove the trim covering the belt assemblies, etc.
• Disconnect the negative (-) terminal to the battery!  You must do this to avoid any issues with the pretensioner unit, either triggering or throwing fault codes.  Also remove the key from the ignition (if you have keyless entry, remove the starter key from the dash).  I have read various opinions on whether this is necessary on the modern P-cars or not, but why take the risk?  The official PAG Workshop Manual (WM 691119) instructs the disconnection of the battery, so I say do it!

Note:  The seat belt pretensioner unit is no longer usable or safe once it is triggered.  The unit triggers an explosive charge to lock the belt when there is an accident, and should then be replaced.  It works in conjunction with the Airbag (except in rear-ender where the airbags won't fire.)  If you need a replacement, you can order from authorized Porsche parts suppliers.

• Lastly, You are going to be working in some tight spaces.  Consider whether it would be a whole lot easier for you if you remove the front seats entirely from the car.  Totally something even the newbie DIY can tackle, and will make your life a lot easier.

Step 1: Remove B-Pillar Trim

• Loosen the three-point set belt bolt found at the bottom near the door sill.  There is a small black plastic cap covering the bolt.
• Using a trim tool or your fingers, grip the belt "collar" trim piece on the B-Pillar on the sides and pull directly out from the pillar. 
• Release the unlocking bracket on the clamps and pull it forward.
• You may need to use a pointy tool or wire hangar bent to release from within the pillar...
• Slide the trim piece down the belt out of the way (exposing the seat belt mounting points which were concealed by the trim piece).

Step 2:  Remove the Rear Side Panel Trim

• You may want to remove the C-Pillar trim piece (upper trim piece where the rear seatbelt enters the roof-line belt collar - and you will need to remove this piece if you are replacing the rear seat belts...) first.  The trim pieces for the side panel, roof panel, and C-panel all come together back there, and it may be less risky to remove the C-pillar trim first.
• Remove the rear seat cushions -- you can just lift up and pull forwards.
• Unscrew the rear seat back locking pins from the side panel -- using a socket or drill with appropriate bit ( I believe this is a T25 bit), unscrew the locking pin and place aside.  This is the only fastener holding the panel in place.
• Grabbing the side panel trim at the bottom and top, pull the side trim panel up and swivel it inwards from the top towards you.
• Disconnect the electric connector to the side panel speaker
• Pull the backrest bearing collar inwards and off.

Step 3:  Unfasten Front Seat Belt Mounts

• By the door sill, locate the lower mounting point of the front seat belt, which you loosened previously.  There is a plastic cap over the bolt --  remove the protective cap.
• Using an appropriate Torx, unscrew fastening screw and remove belt fitting and spacer sleeve.
• At top of the belt, at the B-Pillar, use your Torx to unscrew and remove fastening screw.
• Pull the belt strap out of the guide bar.

Step 4:  Remove Seat Belt Pretensioner Unit

• Moving down the B-Pillar, locate the Pretensioner unit.
• There is a single fastener holding the pretensioner unit to the pillar.
• Using your Torx, unscrew the fastener.
• Pull the pretensioner unit up and out of the pillar.

NOTE there are electrical connection(s) to the pretensioner!  There are variants, based on geographic region.  Following is for USA.  Rest of world there is only a single electrical connection -- I can't confirm this, but if you find one or more connectors, they all work the same way.

• Release the locks on the electric connectors (USA) on the seat belt pretensioner using a screwdriver.
• Disconnect connectors

And you now should have the entire seat belt assembly removed from the car.  Carefully wrap the removed / stock pretensioners and seat belts and store someplace safe -- or if the pretensioners have already been triggered slice the belt and toss since like an airbag, the pretensioners shouldn't be reused once triggered.

To install new belts and pretensioners, follow the above steps in reverse order.  Also, note that when hanging the new belts, you will want to "turn" the lower mounting plate of the belt 180 degrees before fastening-down.  

If you are tackling this project and take some pictures, I would be happy to post them and give you photo credits!  I think some pictures of the pretensioner, trim panels removed of that area would be very helpful to others!