Hydro boost issues

[Hydratech®]

Your description actually sounds to me like more of a conventional brake problem as opposed to a problem with the hydraulic brake assist unit itself. My thoughts are that you should thoroughly bleed your brakes (especially from sitting so long / age), adjust up your rear brakes (if drum or calipers with integral e-brake). It is also possible that your master cylinder may be starting to ail (corrosion pitting inside the bores from moisture in the brake fluid). If that doesn't clear it up, read up further: http://www.lateral-g.net/forums/showthread.php4?t=27741