The power steering leak was from the low pressure hose. The hose had dried out, and cracked. There were many little cracks along the length of the hose, and the hose "weeped" fluid. I replaced the hose with p/s hose from a hydraulic shop, along with 2 new clamps and presto! problem solved. The hardest part was getting my chuppy little paws in to remove and replace the hose, which ends down behind the pump.
Look at the ends of the hose, down behind the pump. You can almost see where it ends if you look hard. The hose is only a foot long, (rubber part), and about 7/8" diameter. The low pressure side has hose clamps, while the high pressure uses fittings.
As far as the cold and your rear suspension: The pump is mounted to the front timing case of your engine, and this should heat the fluid up. Unless the fluid does not mix with the fluid in the shocks? Not sure on this one, as we don't get much of that cold stuff here in sunny florida!
Good luck! and keep warm.....
1989 560SEL (172k)
1989 325IC (122K)
2004 Suzuki Volusia LE (3500 miles)
2005 Yamaha Road Star (20 K miles)