Seat Belt Systems: Description and Operation

Seat Belts

An inertia reel, three point seat belt is installed at each seat position (front and rear). The front seat inertia reels incorporate a lift shaft locking system with webbing sensor and car sensor activating mechanisms. The webbing sensor activates the locking system if the webbing is subjected to a sharp pull. The car sensor activates the locking system if the vehicle is subjected to sudden deceleration or a severe tilt angle.

The inertia reel of each front seat belt is attached to the body B post, behind the rear quarter trim casing. A locating peg on the top front of the pre-tensioner unit mates with the B post to prevent rotation, and a bolt at the base of the unit secures the pre-tensioner to the body. The seat belt webbing runs from the inertia reel, up to a height adjuster on the B post to an anchor rail just above floor level. The height adjuster unit is attached to the upper B post by two Torx screws and the webbing runs through a 'D-loop', which is attached to the adjuster by a Torx bolt. The seat belt fixing point of the mechanism slides up and down the adjuster to provide the required seat belt setting. The webbing then passes through an aperture in the B post upper trim and the long end is attached to an anchor rail which is secured to the floor panel cross member at the base of the B post.

Buckle
The buckle assembly for each seat belt is attached to the inboard side of each seat frame and incorporates a flexible stalk and pre-tensioner.

Warning Switch
Seat belt warning switches are fitted into both front seat belt buckles. Both the driver and passenger buckle switches have three-wire switches, all of which are connected to the MRS control unit.

Inertia Wheel
The inertia reel of both rear seat belts are attached to the body inner rear quarter panel. Each inertia reel is fixed to the body rear inner quarter panel by a bolt with a locating tag holding the assemblies in position on the body.

Webbing
The seat belt webbing passes from the inertia reel through the C post upper trim with the long end of the webbing secured to the body rear inner quarter panel. The buckle assembly for the rear seat belts is mounted directly to the body floor via a mounting bracket. This mounting bracket is secured by a single Torx bolt.

Seat Belt Pre-Tensioners - Pyrotechnic

Both Driver and Passenger seat belt pre-tensioners are mounted to the seat cushion frame on the inboard edge (as shown below).

ISOFIX Brackets
The MINI COOPER is equipped with ISOFIX points for child seat retention. The ISOFIX brackets are accessed through trim plugs in the rear of the seat cushion. These brackets (as shown) are attached directly to the body.