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not affected.) The cost to carmakers should a mandatory recall become a reality was estimated at
U.S. $109.
Ultimately, this incident did not result in a formal mandatory recall by the U.S. National
Highway Traffic Safety Administration. The manufacturer of these seat belts, the Takata Corpor-
ation, and the affected automakers agreed to a voluntary recall of these vehicles. The following
excerpt is from a recall letter from Honda to owners of the affected vehicles:
The Reason for This Notice: Honda has determined that front seat belt buckle release buttons
have broken, and others may break in the future, in some (1986-91) Honda cars equipped with
seatbelts made by the Takata Corporation. These seat belt buckle release buttons are made of
red plastic, and are marked PRESS. If a button breaks, pieces may fall into the buckle assembly.
If this occurs, the buckle may not operate properly, thereby creating a safety risk. To prevent
this problem from occuring, Honda will replace all broken front seat belt buckles, free of charge.
In addition Honda will modify all unbroken buckles manufactured by Takata to prevent future
button breakage.
Under the terms of the voluntary recall, owners of affected vehicles were asked to take their cars
to their dealer who would perform an inspection and then either replace or modify the seat belts.
The details of the inspection and modification procedure are described later in this report.

2. The seat belt mechanism and its failure

2.1 The seat belt mechanism
While there are some variations in design among the various models of Takata-manufactured
seat belts affected, the basic mechanisms are quite similar. All include a release button, which is
part of the seat belt receptacle mechanism, that is adjacent to the slot into which the seat belt clasp
fits when the belt is engaged. A typical Takata seat belt receptacle of the affected design is shown
in Fig. 1.
In order to understand the function of the release button, and how it contributes to the various
system failures, it is necessary to first understand how the seat belt receptacle mechanism works.
A schematic of the seat belt latching mechanism is shown in Fig. 2. In the top part of the figure,
four key parts of the mechanism are shown and named. (Other parts are omitted for simplicity.)
In the middle part of the figure, the steel ‘clasp’, at left, is inserted towards the right into the
mechanism where it encounters a polymeric ‘slider’. The clasp forces the slider to compress a
spring. In the bottom part of the figure, the ‘latch’ and ‘locking slider’ rotate counterclockwise
into the locked position when the opening in the clasp becomes aligned with the male portion of
the latch. As the latch rotates into the locked position, the locking slider slides to the left into a
position where it is constrained along with the latch (by the unshown housing) from rotating back
to the unlatched position. To release the belt, the release button is pushed against the locking
slider, sliding it back out of the way of the housing, and allowing both the locking slider and latch
to rotate clockwise until the male portion of the latch no longer engages the opening in the clasp.
Finally, the compressed spring behind the slider can extend itself, ejecting the clasp from the
mechanism.