recap: i asked how to remove the back rest to find the annoying tapping sound (while driving) from the rear panel that is gettin' worse.

525SEI BRIT responded with possible causes, and bill g sent links with pictures how to remove the back rest. thank you guys. saved me tons of time.

now, i managed to removed the back rest, and still couldn't figure out what is that tapping sound; however, i locked in the source (it's in the left rear with metal to metal hitting each other sound). took it to my mechanic today, and he showed me there is a hairline crack in the body (rear-left next to the shock). this is my first encounter with hairline crack in the body of the car.

my mechanic applied some wd-40 on the hairline crack. annoying tapping sound is gone! he said that the possible cause of the hairline crack was due to my aftermarket wheels (20 x 8.5 all corners). i'll be back on his repair shop to monday to get the hairline crack welded before it gets worse per my mechanic's advice.

are bmw e34s prone of hairline cracking of the body? especially near the shocks. anyone have similar experiences?