Abstract: The rear axle suspension system is retrofittably attachable to spaced-apart suspension mountings of an ambulance type of vehicle. The suspension system has an axle bearing arm having a first end that pivotally connects with one of the suspension mountings, and an opposite second end. A complementary arm has a first end that pivotally connects with the other one of the suspension mountings, and an opposite second end pivotally connected to the second end of the axle bearing arm. An axle bracket is secured to the axle bearing arm at or near the second end thereof, to receive the rear axle. A pair of spaced-apart absorber bearing arms downwardly project respectively from the axle bearing and complementary arms and face each other. A shock absorber is mounted between the absorber bearing arms.