Hello, I have a Citroen Zx 1.4i, heck built in 1996. Now the rear brakes are grinding, after 2-3 brakings and I then need a little more motor force to drive. Sometimes there is also a small ruck, and the brakes dissolve quite suddenly. I don’t know now if they are purely dirty brake blocks, or the brake power amplifier can be. So that suddenly the valve opens up. Sometimes it whistles also n n bissel back when I step on the brake. Do I have to change the brake drums when I have been driving around for too long? I wanted to order these sets now and then go to my private workshop:http://www.ebay.de//130571073690?…http://www.ebay.de/…/360260181246?…