REVISED TREADLE ANGLE (NEW TREADLE & PLATE RELEASED)

SUBJECT: REVISED TREADLE ANGLE (NEW TREADLE AND PLATE TO ENHANCE DRIVER ERGONOMICS)

VEHICLES AFFECTED: 1988-89 S7 FORWARD CONTROL SCHOOL BUS

To enhance driver ergonomics, a revised design brake treadle and mounting plate have been released. This revised design positions the treadle to a more vertical angle, eliminating the potential of driver foot fatigue.

Vehicles manufactured beginning with the following VIN breakpoints are equipped with the redesigned treadle and mounting plate:

GMC: KV513997 Chevrolet: KV109739

To update vehicles manufactured prior to these Vehicle Identification Numbers, the following procedure should be used:

Service Procedure: (Figure 1) ---------------------------- 1. Remove cotter pin from fulcrum pin.

2. Remove fulcrum pin from treadle and mounting plate. Lift treadle from plate.

3. Loosen and remove three nuts and washers securing mounting plate to application valve studs.

4. Unscrew and remove three bolts and washers securing mounting plate to floor.

5. Position new mounting plate on floor and onto application valve studs. Install three bolts and washers to secure plate to floor. Torque bolts to 40 Nm (30 ft/lbs).

6. Install three nuts and washers to secure mounting plate to application valve. Torque nuts to 10 Nm (7 ft/lbs).

7. Position new treadle onto mounting plate and slide in fulcrum pin to hold treadle to mounting plate.

8. Install cotter pin into fulcrum pin.

9. Depress and release treadle a couple of times to assure proper operation of the treadle.

10. Road test vehicle to assure proper operation.

Parts Information

New Part Number Description Quantity --------------- ----------- -------- 15648827 Mounting Plate 1 15648828 Treadle 1

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.