1. Verify that the joint shaft is not twisted or cracked.
2. Turn the joint shaft by hand and verify that the bearing rotates smoothly and freely.

Drive shaft
Joint shaft removal/installationMazda 6 Service Manual: Front brake (disc) inspection
Brake Judder Repair Hint
Description
Brake judder concern has the following 3 characteristics:
Steering wheel vibration
Steering wheel vibrates in the direction of its rotation. This characteristic
is most noticeable when applying brakes at a vehicle speed of 100-140 km/h
{62.1-86.8 mph}.
F ...
Mazda 6 Service Manual: Front upper arm inspection
1. Remove the upper arm from the vehicle.
2. Inspect for damage, cracks, and bending.
3. Inspect the ball joint rotation torque.
(1) Rotate the ball joint five times.
(2) Measure the rotation torque using a suitable allen socket and a
torque wrench.
If not within the specification ...