Spring Compressors

A deceptively dangerous tool that requires great care for safe operation. They allow you to remove pre-loaded springs from MacPherson struts in order to change the springs or shock absorbers. They also allow you to safely disassemble a MacPherson strut to re-use the top mount with an aftermarket adjustable coilover strut.

Springs store energy, just like petrol, a battery, or a vehicle which is lifted above the ground. The springs in your car are capable of holding up a car, which means they can store a very large amount of energy and release it immediately. This presents a great danger when the spring has the ability to rapidly decompress.

Before removing the MacPherson strut from your vehicle, loosen the nut at the centre of the top mount SLIGHTLY. DO NOT REMOVE IT YET. This nut holds the pre-load on the spring, and removing it when the spring is not compressed will send the spring flying extremely far and fast. You will likely need to turn the nut against an Allen or torx key in its centre. Turning one without bracing the other just damages the shock absorber by spinning the shaft in circles.

Clean and oil the threads before use. Run the threads across their full length to check for any binding. Set the length of the spring compressors to about half way along their threads, and position them on opposite sides of the coil spring. Mount the MacPherson strut in a bench vice. Tighten each compressor alternately so as to keep the spring straight - do not allow it to bend from one spring compressor being tighter than the other. Continue until all pre-load is removed from the spring and it is no longer touching the top mount. Remove the top mount nut which was loosened earlier. Carefully move the spring to a safe location lying down on the floor, pointing at a wall, preferably with something between the spring and yourself. Loosen the spring compressors alternately so as to keep the spring straight. The spring will reach a length greater than when you started, as it is no longer constrained.

  • If you've never used spring compressors before, ask for help. They can be a very dangerous tool.
  • Don't remove any nut that's still holding a spring which is loaded against that nut.
  • Don't have a compressed spring which is no longer contained by the shock absorber and top mount pointing toward any person or pointing upward. Keep the spring pointing at a wall from a fair distance.
  • Have a soft but heavy cover such as an old blanket in the path of the spring when it is free from the shock absorber and top mount. This will dampen any bouncing in the case of an accident, so that the spring will stop when it hits the wall, rather than bounce back at any person.
  • Don't allow the spring compressors to slide around to the same side of the coil spring.
  • tools/mechanical/spring_compressors
  • Last modified: 22 months ago
  • by unmeg