Tom Tom One XL attachment point 'swivel'.

My Tom Tom One XL GPS is functioning perfectly even though it is many years old. My challenge is this - The windshield attachment arm connects to the GPS unit bracket by means of a 'ball joint'. The 'ball' is part of the windshield attachment arm. The 'joint' is on the back of the GPS unit bracket and is held in place with two Phillips screws. Inside that joint is a soft-plastic grommet providing the friction necessary to hold the GPS unit in the desired position. That soft-plastic grommet has evidently decomposed over the years and lost its ability to hold the GPS unit in position. Is there somewhere I can find a new grommet so I can restore the function of the mounting hardware?