Yesterday I took my 2000 Vitz for service. I got the wheel off had the washed and swapped the front wheels with the rear ones.

After service i am having 2 issues

1. A "Knocking Sound" is coming from the rear passenger side wheel every time i Brake. The sound is loud enough to be clearly heard apart from that braking is fine and car is not pulling towards any side. Today i went to the mechanic and had the brakes services (just in case) but the sound is still there, i intend to go back again and get the car on the lift and check from under the car for any problem. Any similar experience/knowledge would be appreciated.

2. Also after the service during which the engine was also washed, when running on CNG and specially with AC running the car starting a small bit of Missing. It feels as if the AC is tripping again `n again. I check and saw the emulator's body broken from one side & good chances are water/moisture did go into it. This problem is only when on CNG, while the car runs smoothly on Petrol both with and without the AC turned on. Shall i get the Emulator checked if it has been damaged by the moisture?