Description Modified Bracket Now Fits 2007 Silverado/Sierra Applications. Releases Tension on Both Large and Small GM Single Spring Brakes During Servicing. Many GM brakes use a heavy single spring. The 50600 engages the spring and quickly releases the spring tension. The brake can then be disassembled to replace brake shoes, emergency brake cable or service the brake cylinder. Also works on older C & H body vehicles with single brake springs.