I have a 2007 ford focus and the power steering is making noises and after I shut off the car it starts to leak fluid around the cap. I have taken it to the shop and they changed the pump, resev., and flushed it and it still does it. I think it is a leak somewhere because it causes the fluid to be foamy. What do you think?
Could be a leak on the return line or at the reservoir return o ring. Have them pull vacuum on the system and see if it will hold. This will also bleed the air out of the system if there isn't a leak. You should also use Mercon V instead of the generic power steering fluid if you aren't already.
The reason the fluid overflows like that is because of the aeration of the fluid and the power steering pump putting pressure on the system.