How would i go about taking out the rear deck and the seat back ?

Seat Cushion Replacement - Rear
Removal Procedure




Push the lower forward edge of the seat cushion (1) rearward.
Lift upward and pull forward on the seat cushion frame in order to disengage the cushion frame wires (3) from the retainers (2) on the rear seat pan.
If the cushion is difficult to disengage from the seat pan retainers, grasp the lower edge of the seat cushion at the retainer location on one side of the seat. Exert enough rearward pressure in order to disengage the seat from the retainers.

Installation Procedure


Carefully lift the cushion into the body. Do not damage the adjacent trim.
Position the rear edge of the cushion under the rear seat back while you position the seat belt straps.
Align the frame wire offsets (3) at the front of the seat cushion frame with the retainers (2) on the floor pan. Push the seat cushion rearward until the offsets engage in the retainers. Fully engage the retainers by pressing down and pulling the cushion forward.
If the cushion is difficult to engage to the seat pan retainers, grasp the lower edge of the seat cushion at the retainer location on one side of the seat. Exert enough rearward pressure in order to engage the seat into the retainers.

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Document ID# 299742
1999 Pontiac Bonneville

Seat Back Replacement - Rear
Removal Procedure
Remove the rear seat cushion. Refer to Seat Cushion Replacement - Rear .
Remove the following components from the inner studs:
The lap belt nuts (3)
The lap belts (4)
Remove the push-nuts from the outer studs.
Remove the rear seat back from the vehicle.



Perform the following steps in order to remove the armrest (6), if applicable:
Remove the bolts (5) from the seat back.
Remove the pivot screws (4).
Remove the armrest (6).
Remove the hog rings (7) from the seat back frame
Disengage the hook and loop strips (2).
Remove the cover (1).
Installation Procedure




Install the cover (1) over the pad (3). Align the locating holes ( in the cover to the work lines (9) in the pad.
Install the hog rings (7). Work outward toward the corners until you have installed all of the hog rings.
Turn over the seat. Engage the hook and loop strips (2).
Perform the following steps in order to install the armrest (6), if applicable:
Secure the armrest (6) to the support with pivot screws (4).
Attach the armrest (6) to the seat back with bolts (5).
Install the rear seat back.




Notice
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.


Install the lap belt nuts (3). Tighten
Tighten the lap belt nuts to 35 N·m (25 lb ft).

Verify that the shoulder belts (4) operate freely.
Install the rear seat cushion. Refer to Seat Cushion Replacement - Rear

Document ID# 299702
1999 Pontiac Bonneville


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Trim Panel Replacement - Rear Quarter
Removal Procedure
Tools Required
J 38778 Door Trim Pad Clip Remover





Grasp the roof inner side rear finish molding next to the upper quarter trim panel.
Pull the molding toward the front of the vehicle in order to loosen the molding from the body.
Disengage the retainers on the backside of the upper quarter trim panel (1).
Pull the panel toward the inside of the vehicle.
Remove the upper quarter trim panel (1).
Installation Procedure




Install new retainers to the upper quarter trim panel (1) if the retainers are broken or damaged.
Align the upper trim panel retainers to the holes in the body panel.
Press the trim panel (1) into place.
Align the inner side rear finish molding to the body.
Press the molding into place in order to secure.

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Document ID# 299702
1999 Pontiac Bonneville

Document ID# 416245
1999 Pontiac Bonneville


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Trim Panel Replacement - Rear Window Shelf
Removal Procedure




Remove the rear seat back. Refer to Seat Back Replacement - Rear in Seats.
Remove the rear quarter trim panels. Refer to Trim Panel Replacement - Rear Quarter .
Remove the push-in retainers at the front of the rear window trim panel.
Lift upward the rear window trim panel.
Carefully guide the rear shoulder belts from the opening in the rear window trim panel.
Pull upward the rear window trim panel.
Remove the rear window trim panel.
Installation Procedure




Install the rear window trim panel.
Carefully guide the rear shoulder belts through the opening in the rear window trim panel.
Install the push-in retainers at the front of the rear window trim panel.
Install the quarter trim panels. Refer to Trim Panel Replacement - Rear Quarter .
Install the rear seat back. Refer to Seat Back Replacement - Rear in Seats.

This write up shows how it is done. https://www.gmforum.com/performance-137/weight-reduction-tips-racing-seats-281813/

Nice write up Dan you guys have covered alot of areas, Good pics I just never know.