Most folks are focussed on pads and discs when servicing brakes with a dab of the right lubricant here and there – ProSlip! The forgotton player is undoubtedly the piston seal. We view the seal as just a way to keep brake fluid in – but the seal plays a major role in making sure the piston sits back off the disc.
The seal deforms when the brake pedal is pushed, when released it wants to resume it’s shape and as it does so, pulls the piston back. Remember we are talking micro movements.The material of the seal is calculated to deform and reform correctly. Not only that but groove the seal sits in is cut at an angle to facilitate this process. This angle isn’t selected at random but is chosen after lengthy bench testing.The material of the seal is also chosen carefully.
The ProSlip Way video shows a method of lubricating the piston seal. This is important in order to facilitate the recoil of the piston. It should now be clear why corrosion under the seal can disrupt this carefully thought out process