Bulletin updated September 2008
This safety bulletin only applies to PRB/Birkin S3 clubman with Independent Rear Suspension (IRS) resold by PRB in 2005.
Other PRB models are not affected
Failure of two cast alloy rear suspension uprights have been reported to PRB. These failures resulted in detaching of the main wishbone mounting, and/or toe adjuster mounting from the main body of the rear upright. Fatigue related cracks have also been found in the body of the uprights.
Both of the failures reported resulted in loss of vehicle control due to sudden loss of rear wheel location.
The following pictures detail the locations of the failure and where cracks have been found. Cracks are visible to the naked eye. A die penetrant crack testing compound has been used to facilitate photography of the cracks.
Image 1 - Failure of attachment of toe adjuster linkage to upright |
Image 2 - Failure of main wishbone to upright attachment |
Image 3 and 4 - Details of main wishbone attachment failure |
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Image 5 - Die penetrant detail of crack in upright |
Image 6 - Die penetrant detail of crack in upright |
Although Birkin Cars in South Africa, and their local agent Birkin Sportscars Pty Ltd, have continued to assert that there are no issues with the design or construction of the rear uprights, they have since made two statements:
1. That Birkin cars are not warranted for racetrack usage
2. That they have developed a strengthening plate for the rear uprights, and are offering to supply these plates for no cost. However they must be factory-fitted, to existing uprights, at a cost of $290 per car
Given that only two owners have decided to have the strengthening plates fitted, PRB Australia has decided to initiate an upgrade program. PRB Australia will pay for the fitting charge for any owner who requests that the strengthening plates be fitted, and the PRB agents at the time will also provide assistance in removing/refitting uprights.
PRB recommends that PRB/Birkin S3 IRS cars with uprights of this design should not be driven under conditions that could cause high suspension loads. This includes any driving on race tracks, competitive events or roads with severe bumps or uneven surfaces.
PRB has contacted all owners of the affected cars, with a strong recommendation that they participate in the Upgrade Program, which will remain in operation till Dec 15, 2008. It is hoped that all owners will respond, resulting in all cars being fitted with the factory-supplied strengthening kits.
PRB is undertaking this program as we believe it will significantly enhance the durability of the rear uprights, and upgrade all cars sold by PRB to the same state as kits which are currently being sold by Birkin Sportscars Pty Ltd.
