When servicing front struts on 1988-90 'W' Models for a leak condition, strut cartridges, P/N 22074850, should be utilized in lieu of complete strut assemblies.
Parts are currently available from CANSPO.
Replacement procedures are outlined in the following service manuals:
1988 W Body Page 3C-4 and 5 1989-90 W Body Page 3C-3 and 4.
Use appropriate Labour Operation, "Cartridge front shock absorber/Strut-replace" found in the respective Labour Time Guide.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.