if your oil level is right your oil pressure light will still come on, i read it in the series 3 handbook. Your brakes are drifting to one side beacause they either need adjusting or your wheel cylinders are leaking and brake fluid has gone all over the shoes- this happens when you leave all the mud in your brakes after off roading in muddy puddles, has happened to me twice and it is a real [!Expletive Deleted!] putting new wheel cylinders on especially if your brakes lines are siezed onto the nut!!!