BRAKE PRO, LTD. TECH BULLETIN

For your information

RELINED BRAKE SHOE INTEGRITY
Relined brake shoes are essential to every-day business in friction relining. When the friction material is installed on the steel shoe that is being re-used, it is supposed to be ready for use. However, the technician's careful inspection of the shoe and the friction before installation is essential to insure that the brake shoe and friction will function properly when in service. Most brake shoe reliners do careful inspection, and many brake shoes are rejected for a variety of causes. It is up to the installing technician to carefully inspect the brake shoes and friction before installation to insure that there are no defects.

WHAT TO INSPECT
Is it the right shoe?
The shoe table being removed should be compared to the shoe table to be installed. Looking at the type of shoe, steel or cast, is the first and most obvious inspection to do. If there is an obvious difference, the shoe should not be used. Checking for the right mounting surfaces, the right contour, and the right amount of spring holes and mounting bosses is also essential.
Is the shoe aligned correctly?
Originally brake shoe steel is designed to insure that the friction material is aligned properly for actuating the brakes in a manner that will allow them to work without moving around and causing brake pulls. You should inspect with a gauge, such as a Frasier Gauge, that will allow you to check the shoe alignment. This will insure that the brake shoe is in alignment and that all of the mounting bosses are exactly where they should be. The Frasier Gauge also will allow you to check the anchor pinholes' dimensions to assure that there will be no excess play when they are installed.
Is the shoe table flat and rust free?
Brake shoe tables are designed to run flat to the surface of the brake drum. Re-used brake shoes have been used, and they do become rusted and bent in normal use. The reputable reliners find most of this rust and bending, and the shoe is discarded and not reused. Careful inspection of the installed friction material to insure that there are no gaps and separations between the friction and the shoe table is essential.
Are the rivets or bolts secure and tight?
Attaching the friction material correctly to the shoe table is very important. If the rivet holes or boltholes are larger than the dimension specified, it will allow the friction material to move around and come loose. This will cause loss of braking and severe damage. Elongated rivet or boltholes are cause for rejection and cannot be accepted in a relined shoe.
The installing technicians responsibility is to insure that all components installed in a brake reline will serve to make the braking system function as it was intended to function. The careful inspection of all brake shoes and linings will insure that problems are not encountered after installation.

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