Q: Should Coil Springs/Shock Absorber Assemblies Be Replaced in Pairs on Toyota Prius?
A: Shock absorber and coil spring assemblies should only be replaced in pairs. For 2009 and earlier models, begin by removing the safety plug from the high-voltage battery, then raise the rear of the vehicle and support it securely on jackstands before removing the rear wheels. For 2003 and earlier models, remove the rear seat, disconnect the speed sensor wire if it interferes, support the rear axle with jacks, and remove the upper fasteners and lower mounts of the shock absorber. For 2004 through 2009 models, remove the rear seat back framework and right side trim panel, unclip the battery cooling duct, and remove the high-voltage battery reinforcement to access the shock upper mounting fasteners. Support the rear axle with a jack, remove the upper fasteners, and guide the shocks out. Follow inspection procedures to determine if the shock absorber assembly needs disassembly for replacement. For installation, maneuver the assembly into place, install the lower mount, raise the axle beam to simulate normal ride height, and tighten all fasteners before reinstalling the wheels and lowering the vehicle. For 2010 and later models, remove the rear floorboard and storage box, sill plate, tonneau cover holder caps, armrest side panels, and luggage tie-down assemblies, then raise the vehicle and support it securely on jackstands. Detach the ride height sensor if applicable, compress the coil spring, and remove the shock absorber components. Follow inspection procedures and replace shocks in pairs. For coil springs, raise the vehicle, disconnect the speed sensor wiring, detach height control sensors if applicable, and access the axle beam pivot bolts. Compress the shock absorbers, remove the bolts, and lower the axle beam to remove the coil springs. Installation is the reverse of removal, ensuring not to tighten the axle beam pivot bolts until the vehicle's weight is on the wheels, followed by bouncing the rear and tightening all fasteners.