OOSC, Part II, Item 1. Brake Systems, a. Defective Brakes - Loose Brake Calipers
| Entry Date | June 13, 2008 |
|---|---|
| Issue Number | 08-026-VEH |
| Name | Wes Roth |
| Agency | Alberta Transportation - Commercial Vehicle Enforcement |
| Address | #346 - 3 Street SE, Room 6Medicine Hat, AB, T1C 1R5CanadaMap It (opens in a new tab) |
| Phone | (403) 529-3540 |
| Fax | (403) 529-3684 |
| [email protected] | |
| Committee | Vehicle Committee |
| Status | Closed |
| Summary of Issue | The brake caliper V-ways and brake caliper mounting plate support rails will wear and eventually cause the brake caliper to fit loosely. The OOSC does not include excessively loose calipers for hydraulic braked vehicles. Manufacters of floating caliper type disc brakes address this issue as a rebuild of the caliper and anchor plate assembly. For this type of caliper the rebuild allows for wear up to 0.145 inch (1/8\")to be correct by shimming/keying the looseness measured at the bumper gap. Looseness in excess of 1/8\" is excessive and requires replacement of the caliper or anchor plate or both.Attachments include:1. Installing Caliper Bumper Gap Shims on All-Makes Hydraulic Disc Brakes Kit E-6890 Meritor Heavy Vehicle Systems.2. Video Clip showing excessively loose floating caliper type disc brake.3. Floating Caliper Type description document.4. Freightliner Business Class Trucks service manual brake Caliper rebuild exerpt.5. International Truck Caliper Service. |
| Justification or Need | Excessively worn caliper and/or anchor plate on a hydraulic disc brakes floating caliper design may cause uneven pad wear and braking as the caliper twists in the anchor plate housing during braking. Additionally the caliper may eventually completely seperate from the anchor plate causing complete loss of braking on that wheel. This type of caliper is used on steering axle of several manufactures business class trucks and school buses.Currently the OOSC does not include excessively loose calipers for floating caliper type disc brakes in Part II, Item 1. BRAKE SYSTEMS, a. Defective Brakes. |
| Request for Action | Include in the OOSC proposed amendments as inserted below (b) Caliper to anchor plate looseness exceeds 1/8" at the bumper gap. (6) Hydraulic and Electric Brakes. (b)Caliper to anchor plate looseness exceeds 1/8" measured at the bumper gap. This amendment would be similar for loose wheel end components for air braked systems as in the OOSC under Part II, 1. BRAKE SYSTEMS, a. Defective Brakes, (3) Loose brake components including air chambers, spiders and cam shaft support brackets. |