Center Joints (Polhem Joint)

WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.

There are Polhem joints fitted between front and center pipe sections as well as between center and rear pipe sections. Their function is to handle the angle difference between pipe sections. The joints are angled 45 degrees in relation to each other to avoid vibration.

The Polhem joint consists of two forks, produced in forged steel which grip a cross by means of arms. The pins of the cross are mounted in needle bearings in the forks' bearing sleeves. The sleeves are permanently locked in the forks by means of compressive strain.

The bearing sleeves are permanently lubricated with synthetic special grease which contains molybdenum disulphide.

The drive shaft universal joint is friction welded to the relevant pipe section and constitutes one unit together with the propeller shaft.