Dear Friend,
Let me share my experience, few months back i did some engine work and after that when i applied the brake tuk tuk sound comes and some time on uneven road (not bumby) the sound comes.
Before the engine work their was no sound at all, so machine told me that it is the exel and even he bring out some suspention wala woh told that ur excel length is not right, i almost had a fight with mechanic because i was sure he is trying to fool me.
Finally i visit Naseer Engineering (Saddar Lucky Star) with whom i did suspension work so Naseer Engineering guy (Javed) take a drive and confirm me that no excel work it is some thing related to brakes.
Than i check the same with other suspension wala at Soldier Bazar and he told me we have to check by taking the excel out,so they open and check every thing and every thing was fine and they adjusted the brake as well.
But the problem was related to the foundation, the choria of foundation was completly worn out and that machinic did not change the found when he was placing the engine and it was his mistake.
so i change the founding (2 foundation) and the problem was solved, the engine was moving as i applied the brakes and thats why it is making sound like dug dug or tuk tuk.
so please check the founding as well
Regards,
faizan