Thanks, Scott, for that info. I'll have to check this on my sailboat's pump. Last I knew, Robertson (Simrad) were using Hynautic pumps. Is this the case? BTW, this is another good reason to have the steering pump run off a main engine PTO, IMO, which is what I have. If a backup is wanted, an electric pump could be fitted, too. John "Seahorse" lying St. Augustine Scott wrote: The only 47 on the NAR had two Simrad Autopilots. One failed on the way into Berumda the other failed on the way out. Very simple problem, too much carbon on the brushes.  I clean the brushes and fixed the problem. (Cleaning brushes 30 minutes, cleaning carbon I tracked thru the boat one hour!) This was after 9 months or 1500 hours total operation spilt across both units.