If a customer comes to you with uneven brake wear and you just assume it is a bad caliper and replace it, you may be guessing. Imploded brake hoses and stuck proportioning valves produce hidden symptoms that are not easily diagnosed.
Symptoms of an imploded brake hose occur when the inner nitrile tube of the brake hose ruptures. One reason for an implosion is the use of vice grips to crimp off a brake hose when changing calipers. It is a bad practice since many times it will break the inner nitrile tube, setting the stage for a hose rupture and implosion. Another reason for a hose implosion is at the mechanical connection where the manufacturers clamp the brake hose to the fender wall. Over time, there is a chemical effect between the clamp and the hose causing the inner tube to harden and rupture again, setting the stage for an implosion of the inner tube.
Once the tube rupture occurs and the brakes are applied, the master cylinder has enough pressure to push past the rupture actuating the brake caliper. However, when the brake is released, the implosion acts like a one-way valve, not allowing the fluid to find its way back to the master cylinder or the caliper to allow it to be released. This has all the indications of a stuck slide or frozen piston, but it is only the hose that needs replacement. It is a hard lesson to learn when the car comes back with the same symptoms after replacing all the brake hardware, i.e., rotor, calipers and brakes.
For more on protecting your customers’ brakes, click here to read Test, Bleed, Flush: Protect Your Customers’ Brake System.
Information provided by Innovative Products of America, an original equipment manufacturer specializing in the development of professional tools and equipment.
Check out the rest of the July digital edition of Tire Review here.