Information?? High quality chassis partseries products. Made with high strength steel tubing for superior strength and durability. Stable performance, reliable quality and long service life Uniform thickness, no blow holes, slag, cracks, tearing, or incomplete fusion. Measured by specialized inspection tools after welding to make sure assemble hole , bushings insert, and installation sizes are proper. Professional InstallerisHighly Recommended(No Instruction Included) Alignment Highly Recommended After Install Booster has 2 bolts instead of4 bolts in front of the booster where the master cylinder goesCompatibility Chart?? For 1996 – 2000 Toyota 4RunnerPackage Content?? 1xBrake BoosterWorking principle: A vacuum booster works by drawing in air as the engine is working, creating a vacuum on one side of the booster, The differential pressure relative to the normal air pressure on the other side is used to enhance the braking thrust. Symptoms of a Failing Power Brake Booster: When vacuum booster is damaged, it should be replaced as a whole. Stiff brake pedal that is extremely hard to push Longer stopping distance Engine stalls when brakes are applied Prior to replacing your Power Brake Booster: Ensure the Vacuum Hose is properly connected and not loose Check the Vacuum Hose for a blockage or leak Inspect the Check Valve for cracks, looseness or damage Testing your Power Brake Booster: With the engine off, pump the brakes 5-6 times Turn the engine on while pushing down lightly on the brake pedal If your brake booster is working, the pedal will sink down about ?? If your brake booster is not working, nothing will happen or the brake pedal will push back against your foot