1997 GMC Sonoma Owner's Manual - Page 272

Some driving conditions or climatesmay cause a brake squeal when the brakes are first applied or lightly applied. This does not mean something is wrong with your brakes. Properly torqued wheel nuts are necessary to help prevent brake pulsation. When tires are rotated, inspect brake pads for wear and evenly torque wheel nuts in the proper sequence to GM specifications. Your rear drum brakesdon't have wear indicators, but if you ever hear a rear brake rubbing noise, have the rear brake linings inspected. Also, the rear brake drums should be removed and inspected each time the tires are removed for rotation or changing. When you have the front brakes replaced, have the rear brakes inspected, too. Brake linings should always be replaced as complete axle sets. See "Brake System Inspection"in Section 7 of this manual under Part C "Periodic Maintenance Inspections.'' Brake Adjustment Every time you make a brake stop, your disc brakes adjust for wear. If your brake pedal goes down farther than normal, your rear drum brakes may need adjustment. Adjust them by backing up and firmly applying the brakes a few times. Replacing Brake System Parts The braking system on a modern vehicle is complex. Its many parts have to be of top quality and work well together if the vehicle is to have really good braking. Your vehicle was designed and tested with top-quality GM brake parts. When you replace parts of your braking system -- for example, when your brake linings wear down and you have to have new ones put in -- be sure you get new approved GM replacement parts. If you don't, your brakes may no longer work properly. For example, if someone puts in brake linings that are wrong for your vehicle, the balance between your front and rear brakes can change -- for the worse. The braking performance you've come to expectcan change in many other ways if someone puts in the wrong replacement brake parts. Brake Pedal Travel See your dealer if the brake pedal does not return to normal height, or if there is a rapid increase in pedal travel. This could be a signof brake trouble. 6-34