Except low drag brakes, disc brakes have little clearance between the brake pad and the rotor. As the piston seal retracts, it pulls the piston away from the rotor. If the pad does not retract properly, the brake can drag because the pad stays in contact with the rotor. This friction causes the rotor to overheat and deform. The vehicle drifts or pulls to the side that's dragging.
A restriction in the brake line also causes brake drag. The master cylinder creates enough pressure to bypass the kink, but the return pressure cannot bypass the restriction. The restriction leaves the brake applied.
Brake calipers have a dust boot to protect the piston and seal from road debris and water. Inspect these boots for wear when replacing brake pads. Overhaul kits typically contain a new boot and seal. Square-cut piston seals and other rubber components are sensitive to water, oil, and contaminated brake fluid. Always lubricate the piston seal with clean brake or assembly fluid when rebuilding a brake caliper.
A Square Ring is a sealing device made in the form of a torus (round top view), with a square-shaped cross-section (side view).
Other names for Square Rings are Washer Rings, Lathe-Cut Rings, and TetraSeal©.
The primary reason for using a Square Ring in a sealing application is that they provide more sealing surface area – and at a cost that is comparable to other sealing device. For existing applications, there is no need to change the design or procedures. Square Rings fit in o-ring grooves and are interchangeable size-for-size.
Square Rings are available in a variety of rubber and plastic materials such as NBR, Viton, EPDM, Teflon, etc. In most static applications, a Square Ring will serve as a direct replacement for an o-ring and generally will perform a high-pressure sealing function as well as or better than an o-ring.
For more information or to request a quote on Square Rings, please give us a call at 832-448-5550 or submit the Product Inquiry Form.
We primarily stock American Standard (AS568) sizes of square rings in Nitrile and Viton®. We can also supply Square Rings to metric dimensions.
Standard Square Rings have the same Inside Diameter as the AS568 sizes. However, the Cross-Section dimension is slightly smaller for Square Rings. The chart above shows the Square Ring cross-sections for the American Standard series sizes.
SHOP FOR SQUARE RINGS