You learn something new everyday. This time it was time for me to get myself schooled on the intricacies of the rear disc brake pad replacement.
As shared a couple of posts above I had got a set of rear brake disc pads from Boodmo. Planned to fit it over a weekend and just about got it done after nearly having my plans derailed.
Tools:
- Jack stand and jack to jack up the car
- 12mm ring spanner. A deep offset ring is most convenient.
- Piece of rough grade emery paper or a rough surface to lightly roughen the surface of the pad before installation
Step 1 : Apply wheel wedges at the front wheels since you would not be able to put the handbrakes. The handbrake should be release otherwise the rear pad cannot be removed.
Step 2 : Jack up the rear of the car and remove the wheel. Safety calls for using the wheel jack only to raise the car and support the car on jack stands while you work.
Step 3 : Remove the rear brake caliper. As indicated in the picture below both caliper nuts have to be removed to remove the pads. This is the first difference from the front calipers. While replacing the front brake pads you can remove just one of the nuts and swivel the caliper on the remaining nut to gain access to the pads and remove them.
In the case of the rear disc pads, you have to remove both nuts and lift the caliper clean off, to access the pads.
Step 4 : Remove the pads but pushing them horizontally out of the retaining clips. Use a paint brush to clear the brake dust accumulated on the disc pad clips, the caliper and the piston.
Step 5 : Replace the pads. The picture below compared the thickness of the old and new pads. I did have around 5k life left on them but decided to replace them as the brake pedal travel was getting too long. The pads lasted for 48,000 kilometers.
I did get some molykote grease with the pads. This is used for lubrication between the metal shims, to lubricate the calipers pins and the seats of the pads. DO NOT apply on the braking surface of the pads.
Molykote paste Applied on the pad. The shim goes over this Step 6 : Since the new pads have a increased thickness, the caliper piston has to be pushed inside to fit it back over the pads. To push in the piston on the front calipers it is simply a case of placing a long T rod horizontally over it and using some leverage to push it in. Easy peasy... However this did not work for the rear caliper piston. A you-tube video threw some enlightenment. The piston had to be rotated clock-wise to push it in. In the picture below you can see some notches on the face of the piston for this purpose. There is a special tool to get this done easily but I made it work using a flat end screw driver and a mallet. Carefully place the flat end on the notch and tap it clockwise to send the piston back in.
Rear brake piston face. The pads are already installed. Tool to turn the rear disc caliper piston. Step 7 : Seat the caliper over the pads and tighten the caliper screws. Do not overtighten. Hand tightening is sufficient.
Old v/s new comparo
Drive on,
Shibu.