I have a better idea. With the spring still in the car, but slightly compressed from full droop, wrap lots and lots of bailing wire around each coil. Then slowly lower the control arm. Remove the bailing-wire-wrapped spring and give it to you child as a toy to play with while you tinker with the car. When ready to re-install, the spring is already wire-wrapped and set to install, no pliers & wrapping needed! Why didn't I think of that before? I could have saved $75 on a rental! What was I thinking!
