Power Steering 2000 S70

[CRF Rider 57]

I have a 2000 S70 that I replaced the steering rack Aug. 2011. The rebuilt rack developed a severe leak in about 8 months. Replaced with another rack - warranty (I'm getting better at the R&R of steering racks!) I noticed the power steering reservior has very high pressure - indicated by a large release of pressure when I remove the cap. There is enough pressure to cause a small amount of fluid to spray out when the cap is removed.

I wondered if there is a system problem that is causing excessive pressure leading to rack seal failure? Anyone experienced anything similar?

Thanks!