1999 "EE" Evinrude 70HP 4-Stroke Service Manual, P/N 787023, Page 194Get this manual
Disassembly &
Before removing the manual release valve, operate the unit to the full UP position, then jog the unit DOWN and loosen the reservoir cap one full turnTo avoid personal injury, always wear eye protection when servicing the hydraulic unitSince there might be significant residual pressure behind some components, cover each component with shop cloth as you remove it
Thoroughly clean the unit before disassembling itScrub all outside surfaces with stiff brush and hot, soapy water to prevent surface dirt from contaminating internal parts
Do not apply heat to the cylinder body or cylindersExcessive heat can cause high pressure leaks or failure of parts
Always use "lint free" shop cloth when handling power trim and tilt components If painting the unit is required, paint it after it is completely assembled Painting of individual components may cause flakes of paint to enter the hydraulic passages during assemblyTape th trim and tilt piston rods before painting