I have this problem also. On the verge of just buying an exchange pump. However, I also have a number of other issues on my engine, and would ideally like an engineer familiar with the BMC 1.8 to have a look. Problems include; fuel pump leak, idle speed, white smoke/steam, belt wear, pulley adjustment. Shaft alignment, exhaust hose, exhaust elbow. Not too bad then! Forgot to say, I am mechanically challenged to the extreme. Location is Torbay. Thanks in advance