That Isn't A Solenoid, It Is The Reserve Pressure Accumulator. The Older Ones Had An Internal Accumulator. That Is The One Pictured. If It Has Low Miles On It, We Could Rebuild It. The Internal Accum Units Hd Loose Spol Valves In Them, And With A Lot Of Miles The Spools Won't Hold The Boost Pressure. We Could Disassemble It And See, Or Set It Up With A Later Unit. Any Way The Hydroboost Is The Best Way To Go. The Steering Box Will Have To Be Exchanged Also, With That Rust Inside. The Rust Will Come Back Up Into The System And Jam The Pump Relief Valve. Just Start Out With All Fresh Components.