Hitting the landing gear while driving

Hu people, I have next problem again. My Alfa 147 JTD 115 PS 1.9 Bj.2004 ,5 door, has low-laying spring by 30 mm lower. Until last time everything was ok, for a week hit on right rear side when I drive on impact holes or road canals, I notice then that is not normal because before was not the case. After my check the spring are completely and nothing is broken as far as the spring leg and also the spring bearing above is also ok. After my measurement on straight level with the customs stick it clearly shows that the right back side where I feel the strike is 1 cm lower than the rear left side. My question now: is the shock absorber in the bucket? My colleague has made the car up and also notices that the hand brake (fixed parking brakes) on right side is too tight d.h.with pulled out Hanbrake the wheel can move hard behind only right side , left side dret, with pulled hand brake, the wheel is fixed again the left side has to start with the left hand brake.