yeah, i had the same problem. the ml's are plagued with the steering clamp coming off- it's pretty much a given...i had to deal with this problem for about 6 months. every day i kept putting more fluid in it, including the stop leak stuff. i had to eventually rebuild the pump and it continued to leak, and just like the above post mentioned it was nothing but a rubber o-ring. the dealer wanted to sell me a new pump, when i just had rebuilt the old one! saved about $1000 using a little intuition and common sense....now it's perfect.