Rear brakes on 2009 Cobalt SS/TC:
Special tools needed:
3/8” drive, 7mm hex bit socket
Piston tool (Harbor Freight has one for $3.99)
Brake parts cleaner
Permatex Ceramic Brake Grease
DOT 3 brake fluid
Rear pads for Solstice GXP / Sky Redline / Saab 9-3 (e.g. Hawk HB478F.605 for HPS pads)
1. Set wheel chocks for the front wheels
2. Jack up the rear of the vehicle
3. Remove wheels (you may want to loosen the lugnuts when the car is still on the ground)
4. Pop off the small plastic caps for the caliper bolts:
5. Insert the 7mm hex bit socket and remove the 2 bolts:
6. Using a flathead screwdriver, gently pry one of the “wings” of the front spring clip out, and remove the other part of the wing. Don’t force it out.
7. Lift up the caliper and remove both pads. They should easily come out of the anchor plate.
8. Loosen the bleeder screw and attach a hose to a suitable container to receive the brake fluid, rotate the piston back using the special tool (clockwise rotation). Tighten the bleeder screw.
9. Install new pads, apply Permatex grease on the anti-squeal pads and corner pad surfaces. Also use it on the caliper contact points and the piston surface.
10. Apply ample grease in the slide pin bushings. There are grease-grooves inside the bushings to retain grease. Apply copious amounts of grease on the smooth part of the bolt. I noticed the factory did NOT use any grease whatsoever, and this can cause binding. Binding calipers will cause the in-board pad to wear out faster than the out-board pad!!
11. Insert the bolts and torque them to 25 ft-lb.
12. Apply some grease on the grooves of the plastic caps and pop them back into plate. Brake grease won’t absorb water so it helps to seal off the slide pin from moisture.
13. Re-install the front spring clip by seating one side first, and then pulling back the “ear” while inserting the tip into the hole simultaneously.
14. Repeat for the other wheel.
15. Re-install the wheel, torque the lugnuts to 100 ft-lb (I usually go a bit lower, like 96 ft-lb because I’m used to it with Ford aluminum wheels).
16. Bleed the brakes. Haynes provides the following order for bleeding the brakes: right rear, right front, left rear, left front.
17. Burnish the pads/rotors in accordance with the pad manufacturer’s instructions.
Here are the new Hawk pads next to the stock pads:
Notice how the stock pads do not have the center groove. This can hinder the clearing of debris or material from the rotor surface.
My theory on why the inboard pad wears out faster than the outboard pad is related to binding. The factory did not use any lubrication on my caliper slide pins/bolts. This can cause the caliper to bind up. I’ve seen factory slide pin bushings before and they all have grooves inside to retain grease. Ford uses a white dielectric grease (silicone grease) that is rated for brake caliper pins. I am surprised GM did not use any, yet chose to seal up the bushing with a special plastic cap. I looked carefully and observed that the slide pin bushing is “sealed”, so you really want to grease it up with the right lubricant. Do not use regular wheel bearing/axle grease because it can mix with water or absorb moisture. Permatex makes a silicone brake lube that handles up to 400-500F while the Permatex purple “ceramic” lube can handle much higher temperatures.
The other factor could be pad material. I’ve had stock factory pads chew up my rotors within 500-3000 miles and the OEM will consider it normal unless the grooves are of a certain width and depth. Some catalogs show the stock pads as “ceramic” and it isn’t unusual for an OEM to equip factory cars with pads that use an organic or ceramic filler material.
The reason I don’t feel the lack of a backing plate contributes to the rotor wear is that many brake applications do not have a backing plate. Ford’s Super Duty trucks and cargo vans have exposed rotors for faster cooling. If any debris does get in there, the pads will generally clear it off and it flows through the groove in the pad.