Tires having unequal contact and grip on the road will cause unequal braking. Tires must be equally inflated, identical in size, and the tread pattern for both the right and left sides should be approximately equal. Refer to Radial Tire Lead/Pull Correction in Tires and Wheels for more information.
A heavily loaded vehicle requires more braking effort. When a vehicle has unequal loading, the most heavily loaded wheels require more braking power than others.
Misalignment of the wheels can cause the brakes to pull to one side. Measure the wheel alignment in order to determine if the wheel alignment affects the braking. Refer to Wheel Alignment Measurement in Wheel Alignment.