Why you should always install new brake shims with new brake pads
DIYers often reuse old brake pad shims and then complain about noise shortly after installing new brake pads. Well guess what? The brake shims play an integral part in reducing brake noise and reusuing old brake shims isn’t smart.
All brake pads make noise when they rub against the rotor. If you think of the brake pad like a stylus and the rotor as an LP record, you can see how the pads “play” the wear grooves on the rotor. Modern brake pad shims are multi-layered with a thin rubber membrane between the two shim panels. The rubber dampens the vibrations. But it can deteriorate and harden over time due to the high heat in braking systems. That’s why it never pays to reuse old shims. If the shims don’t have a rubber layer, the shop manual usually recommends applying a light coat of molybdenum grease between the pad’s backing plate and the shim. Molybdenum grease dampens the vibrations.
In addition to dampening vibrations, the shims also act as a thermal barrier, preventing heat from flowing to the caliper face and piston. That provides constant temperature to the pad, resulting in more consistent braking.
If your new brake pads don’t come with shims, BUY a new set. Then you’ll have a top quality brake job.
©, 2016 Rick Muscoplat
Posted on by Rick Muscoplat