Brake Pad: Service and Repair
FRONT DISC BRAKE PAD CHECK AND REPLACEMENT
Required Special Tools:
^ MB990520 Piston Expander
NOTE: The brake pads have indicators that contact the brake disc when the brake pad thickness becomes 2 mm (0.08 inch), and emit a squealing sound to warn the driver.
CAUTION:
^ Take care not to contact the parts or tools to the caliper because the paint of caliper will be scratched. And if there is brake fluid on the caliper, wipe it off quickly.
^ Whenever a pad must be replaced, replace both LH and RH wheel pads as a set to prevent the vehicle from pulling to one side when braking.
^ If there is a significant difference in the thicknesses of the pads on the left and right sides, check moving parts.
1. Check the brake pad thickness through the caliper body check port.
Standard value:
Minimum limit: 2.0 mm (0.08 inch)
2. When the thickness is less than the limit, always replace the pads at an axle set.
1. Holding the cross spring with one hand, pull the pin out of the caliper
2. Remove the pad from the caliper
3. To measure brake drag force after new pads have been installed, use a spring scale to measure the turning sliding resistance of the hub with the pads removed
4. Clean the piston and, using special tool MB990520, push the piston into the cylinder.
5. Apply repair kit grease to the portions of the pads indicated on the left. At this time, make sure that the grease will not be applied to any other surfaces.
6. Mount the pads to the caliper so that its side with the wear indicator is on the outside of the vehicle. With the rear pads, ensure that the arrow on the pad faces in the same direction as the brake disc turns when the vehicle moves forward.
7. Holding the cross spring with one hand, It pins in the caliper.
8. Using a spring scale, measure the turning sliding resistance of the hub in the forward direction.
9. Find the brake disc drag force [the difference in measurements taken in step (3) and in step (8)].
Standard value: 69 N (15 pounds) or less
10. If that drag force exceeds the standard value, disassemble the caliper assembly. Then check the piston for contamination or rust, and confirm if the piston or the piston seal is deteriorated.