I have only opened one seatbelt assembly for examination. It was a
70's Toyota. This belt had TWO inertia based lock mechanisms.
The inertia pin, which looked like a 2" roofing nail with a 1 oz
fishing weight on the end. The assembly was hung through a small
hole. When the car stopped abruptly the weight would swing and
the head would cock and raise a plate that rested on top of it.
When the plate lifted it would engage the belt reel and lock it.
The other mechanism was a inertia reel. The end of the reel had a
set of fly weights like a centrifugal advance. When the seatbelt
was pulled quickley the weights would fly out and lock the reel.
I guess having independent two locking mechanism would be safer
incase one failed or got a french fry stuck in it.
In cany case, my drivers side lock when pulled and the passenger
side dosen't under the same conditions. The manual does not
mention this behavior. My dealer is replacing the belt. I will
see how the new belt works.
FWIW, I filed a safety report with the NHTSA using their web site.
Here it is, FYI.
>This report relates to your message:
>of 11 Apr 1998 06:49:23 -0400
>
>
>VEHICLE OWNER'S QUESTIONAIRE
>============================
>
>Submission Time: April 11, 1998 01:09:48AM
(hey I was up with the baby)
>
>
> OWNER INFORMATION
> -----------------
>
> NAME: Joseph C. Dille
> ADDRESS:
> Apartment
> Telford, PA 18969
>
>TELEPHONE:
> EMAIL: joe@dille.montgomery.pa.us
>
>Have NHTSA send signature card for authorization: Yes
>
> VEHICLE INFORMATION
> -------------------
>
> VIN: 1B7GL22Y2WS645783
> MAKE: Dodge
> MODEL: Dakota
> YEAR: 1998
>
> ODOMETER: 750
> PURCHASE DATE: 02/28/98
> NEW OR USED: New
>
> DEALER NAME: D'Ambrosio Dodge
> ADDRESS: Lansdale, PA 19446
>
> ENGINE SIZE: 5.2l
> CYLINDERS: 8
>
> FUEL INJECTION: on
> TURBO:
> FUEL TYPE: Gas
> ANTILOCK BRAKES: Yes
> CRUISE CONTROL: Yes
> DRIVETRAIN: Rear
> DRIVER AIRBAG: on
>PASSENGER AIRBAG: on
> 3-POINT BELT: on
> MOTOR BELT:
> 2-POINT BELT:
> BODY STYLE: Pickup Truck
>
>FAILED COMPONENT(S)/PART(S) INFORMATION
>---------------------------------------
>
>COMPONENT: Seat Belt
>
>PART NAME(S): Seat Belt Assembly
>
>LOCATION: Right
>
>NUMBER OF FAILURES: 1
>
>DATE(S) OF FAILURES: Since New
>
>MILEAGE AT FAILURE(S): 0
>
>SPEED AT FAILURE(S) 0
>
>MANUFACTURER CONTACTED: No
>
>NHTSA CONTACTED: No
>
>
>APPLICABLE ACCIDENT INFORMATION
>-------------------------------
>
>ACCIDENT: No
> FIRE: No
>
> DRIVER SIDE AIRBAG DEPLOYED: NA
>PASSENGER SIDE AIRBAG DEPLOYED: No
>
>NUMBER OF PERSONS INJURED: 0
> NUMBER OF FATALITIES: 0
>ESTIMATED PROPERTY DAMAGE: 0
>
>REPORTED TO POLICE: No
>
>
>INFORMATION ON TIRE FAILURE(S) (IF APPLICABLE)
>----------------------------------------------
>
>DOT NUMBER:
>TIRE MANUFACTURER:
>TIRE NAME:
>TIRE SIZE:
>
>
>ADDITIONAL COMMENTS
>-------------------
>
>
>I have a 1998 Dodge Dakota Clup Cab with bucket seats, the seat belt on my the driver's side
>will lock when I pull abruptly on the belt. I believe this is the
>inertia reel doing its job. The passenger's side will NOT lock no
>matter how hard I pull. I think this is a safety defect
>and I took it to the dealer. The dealer will replace the passenger's side seat belt.
>
> I am worried that other Dodge Dakotas may also have inoperative passenger side seat belts.
>
>
Drive Safe,
Joe
>Date: Fri, 10 Apr 1998 21:56:34 -0400
>From: Patrick & Kelly Engram <shetland@pop.erols.com>
>Subject: DML: seatbelt tug test
>
>Sorry Joe, but the proper method of testing a seatbelt is not by tugging
>on it but by subjecting it to the same type of force that it was
>designed to stop. You probably wont be able to in most cases get the
>seatbelt to grab unless you are doing this while the truck is pointing
>down a very steep hill. The inertia pin in the seatbelts locking
>mechanism grabs and holds the belt when there is a sudden change in
>acceleration (in this case it is negative acceleration, also known as
>deceleration-an accident) The inertia pin travels while the rest of the
>mechanism stays relatively stopped, and this is what causes it to
>function. Your tug test takes the change of rate of speed out of the
>equation. Otherwise, it would lock up no matter how easy you pull on
>it.
>Patrick J. Engram
>ASE certified blah blah blah
Joe Dille
Telford PA USA
(joe@dille.montgomery.pa.us)
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