Section 13 - Electrical Equipment - Group 13 Automatic Belt Tensioner (13-05) M11 Page 13-5 Inspect the lower bracket and mounting capscrews. If the bracket is cracked, it must be replaced. The front and rear faces of the lower bracket, where the lower bracket and upper bracket contact, must be flat and parallel. If these surfaces are not flat, the rear face ONLY can be re-faced by milling a maximum of 0.50 mm [0.020 inch] deep to clean up. However, the minimum dimension allowed from the front to rear contact faces of the lower bracket is 210.7 mm [8.30 inch]. Do not re-face the front surface.
If the front surface needs re-faced, or the dimen- sion is less than the minimum allowed, the bracket must be replaced. Automatic Belt Tensioner (Bus Appli- cations) - Cleaning and Inspection for Reuse (13-05) Cleaning Warning: When using a steam cleaner, wear protective clothing and safety glasses or a face shield. Hot steam will cause serious personal injury. Steam clean the automatic belt tensioner. Dry with com- pressed air. Inspection Check the tensioner pulley and body for cracks. If any cracks are noticed, the tensioner must be replaced. Check that the bottom tensioner arm stop is in contact with the bottom tensioner arm stop boss on the tensioner body.
If these two are not contacting, the tensioner must be replaced.