Leaks usually occur in the hoses (37-22-1-120-825 & 826) running between the accumulators (37-21-1-124-595) and the shocks. I replaced the hoses on both sides and both accumulators. It took 1.5 liters of Pentosin (high grade mineral oil) 7.1 to refill. Total cost was $493.12 with my discount. Then found www.gapa.com & saw that I could have gotten the parts for much less! My other sources weren't this inexpensive! Next to go are the shocks -very expensive!! 191,600 mi. on this `88 M5 of my wife's.