by Hib Halverson
If you have a 1997 through 2013 with a parking brake which won’t hold the car on a hill, maybe it’s time for some service work.
The C5 and C6 parking brake system consist of three subassemblies: 1) the parking brake lever, 2) parking brake cables and actuators and 3) small, drum brakes inside the rear disc rotors. There are two adjustments to this system. The first is the “parking brake cable automatic adjuster”. To enable that, apply and release the parking brake handle three times. The second adjustment is the one few Corvette DIYs do and that’s the “parking brake adjustment” which sets the proper clearance between the parking brake shoes and the drums inside the rear rotors.
If you are lucky enough to have a hoist, raise the car waist high. If you’re not one of the fortunate ones, use a floor jack and an 18-inch length of 2×4 to lift the rear suspension cradle. Install a pair of Zip Products jacking pucks (PN X-1107) in the rear frame slots and support the rear of the car on jack stands. More specific jacking instructions along with factory information on the parking brake system can be found in Corvette Service Manuals, many of which are available from Zip Products. Such info, also, be found in ACDelco’s subscription-based, GM electronic service information.
If the car has cast iron brake rotors, remove the rear wheels. For C6 ZR1s and ZO6es with carbon-ceramic brakes, to prevent damage to the edges of the brake rotors, you first must install either the GM brake rotor protectors or a set of Reverse Logic M12x1.5F-200-mm Lug Guides–some call them “wheel hangers.” Only after doing that, do you remove the rear wheels.
C5s have “floating” caliper brakes. C6es have either floating or fixed calipers. Floating calipers slide laterally on pins attached to a mounting bracket which is bolted to the rear suspension knuckle. For the purposes of this article, a floating caliper and its bracket are removed as a unit. Fixed calipers are bolted directly to the knuckle.
In either case, break the two caliper bracket or caliper bolts loose, partially unscrew them and do not disconnect the brake hoses. If you’re working on a C6 with carbon brakes, disconnect the brake pad wear sensors.
With iron brake rotors, you may need to retract the brake pads slightly before you can remove the calipers. On a floating caliper, first, try to slide the caliper outwards by hand. If you can’t, use a C-clamp or large set of tongue/groove pliers for this. Place the inboard jaw over the caliper body and the other jaw on the outboard disc pad. Use a cushioning device (popsicle stick, rubber pad, plastic disc, etc) between the caliper and the inboard jaw to prevent damage to the paint.
If it’s a fixed caliper on an iron rotor, try to push the caliper slightly inboard by hand. Or, use a large set of tongue/groove pliers, one jaw in a rotor vent and the other on the outboard side of the caliper. Again, use a cushioning device between the jaw and the caliper to prevent damage to the caliper finish. Squeeze the pliers just enough to retract the outboard pistons slightly. Then, remove the bolts and lift the caliper off the rotor. Support the caliper with some mechanic’s wire or rest it on the top of the upper rear control arm.
For C6 carbon brakes, piston retraction is not necessary. Remove the caliper bolts then slide the brake off the rotor and either hang it with heavy mechanic’s wire or rest it on the rear upper control arm.
Using needle-nose pliers, remove any rotor retaining washers you find on the wheel studs. Finally, remove the rear brake rotors. If the brake rotors are rusted to the axle flanges, spray a penetrant on the rotor’s wheel mounting flange such that it weeps into the center hole and into the wheel stud holes. “Kroil”, “Aerokroil” or “Silikroil”, all products from Kano Labs, are some of the best penetrants on the market and are available from a wide variety of vendors.
Let the penetrant work for several hours or, better yet, over night. Then try and remove the rotors again. If you have iron rotors, install a large drift punch or long screwdriver into one of the rotor cooling vents and pull outwards. You may need to do this in several vents around the edge of the rotor. If you have carbon rotors, do not pry on them. Install screws into the threaded holes in the wheel mounting flange and use the screws to pull the brake rotor off the hub flange.
Once you have the brake rotor off, what you see is the parking brake shoe and actuator assembly. If the friction material on the shoe is severely worn or the adjustment is extended more than 1/4-inch out of the actuator body, replace the shoe assembly and its tension spring with new parts (PN PB-290) from Zip Products.
Fully retract the adjustment screw. Remove the tension spring, first, then spread the shoe assembly by hand and remove it. Before installing the new shoe assembly, spray the area with brake cleaner and inspect the parking brake actuator and adjuster parts. If they are worn, replace them with new pieces from Zip Products (PN PB299). Install the new parking brake shoe by spreading it slightly by hand then putting in place on the backing plate. Make sure its ends engage the actuator. Finally, install the tension spring.
On C5 and C6, the key to a properly functioning parking brake is getting the adjustment procedure right. To do this you need a “Brake Resetting” or “Drum-to-Brake-Shoe Clearance” Gauge and a set of flat feeler gauges. These tools are available from a number of vendors. We obtained ours from Gear Wrench (PNs 3377 and 161D).
Set the brake rotor, face down on the work bench. Using the inside measuring points of the Brake Resetting tool, gauge the inside diameter of the parking brake drum surfaces. Do this while resting the tool’s arms on the edge of the brake drum such that the inside diameter being measured is perpendicular to the rotor axis. One you have the drum diameter gauged, tighten the tool’s lock nut. Turn the resetting tool to a slight angle to the rotor axis then withdraw it from the rotor.
Now, slide the outside measuring jaws of the Clearance Gauge over the parking brake shoe at its widest point. Then, turn the parking brake adjustment nut such that a .015-in or a 0.38-mm feeler gauge fits between the shoe and the Resetting Tool.
Once you achieve that adjustment, redo the procedure as a double-check then reinstall the brake rotor and any retaining washers. Clean the threads in the brake mounting bracket or brake caliper and on the bolts. Smear a little medium-strength thread locker–we prefer “Permatex Threadlocker Blue Gel“–on the threads of the bolts and run them down hand tight with a half-drive ratchet. Finally, tighten each bolt to 125-ft/lb or 175-N/mm. For its accuracy and ease-of-use, our tool choice for that is a Gear Wrench half-inch-drive Electronic Torque Wrench (PN 85077). If you’re working on a C6 with carbon brakes reconnect the brake pad wear sensors.
With iron rotors, reinstall the wheels. If your working with carbon-ceramic rotors, put the rotor protectors or the Reverse Logic Lug Guides back on, then reinstall the wheels and remove the protectors or Guides. Torque your lug nuts to 100-lb/ft or 140-N/mm using a star pattern and in three increments.
Sit in the car. First, if you had to retract any brake pistons, pump the service brakes a couple of times to reset the pads. Then, apply and release the parking brake handle three times, then set it again. With all the parking brake parts in good condition and proper adjustment, when you set the parking brake on a hill the handle should be at about 1/2-to-2/3 its travel.
01: The ’97-’13 Parking brake assembly.
02: The adjustment DIYs sometimes ignore is parking brake shoe clearance.
03: If you are working on carbon brakes, you must prevent damage to the edges of the carbon-ceramic rotors with either factory rotor protectors or a set of wheel hangers.
04: Shown is caliper removal on a car with carbon brakes. If you have iron rotors, you may need to retract the brake pistons.
05: Sometimes, rotors will be retained with toothed washers. They can be removed with needle nose pliers.
06: With the rotor removed, the parking brake hardware can be inspected. If the parking brake shoe is excessively worn or the P-brake adjuster is more than .250-in out, replace the shoe.
07: To replace the shoe, first remove the retaining spring, then, near its ends, spread the shoe enough to disengage it from the parking brake actuator then remove the shoe. To install it, spread it apart, engage the actuator with the shoe ends and push the shoe in place. Lastly, install the spring. Image: General Motors Co., LLC.
08: A lever (upper right), pivots in the actuator body (center) and spreads the shoe apart to apply the parking brake. Nos 1 and 2, are pushed apart by the lever when the brake is applied. No 3 is the adjuster screw which controls the parking brake clearance. Image: General Motors Co., LLC.
09: If the axle flange inside the brake rotor is rusted, remove the rust with an abrasive wheel. We used a Standard Abrasives general purpose Surface Conditioning Disc in a small air grinder. Do not abrade the parking brake friction surface.
10: Once the adjustment checking procedure is done, abrade the axle flange to remove rust. We use a Kent-Moore Wheel Hub Resurfacing Kit (PN J42450-B) to derust the areas around the wheel studs and a Surface Conditioning disc for the rest.
11: This is a Drum-to-Brake Shoe Clearance Gauge. It slides to adjust to different brake drum diameters and has a lock nut which retains the gauge measurement.
12: For accurate measurement, the line between the two gauge points must be across the drum’s diameter and perpendicular to it axis An easy way to ensure that is to rest the gauge arms on the inside edges of the drum.
13: With the gauge locked, put the gauge arms over the P-brake shoe then use a .015-in feeler gauge to check the clearance. If the feeler gauge will not fit, retract the adjuster slightly just until the feeler gauge slides between the gauge and the shoe. If the gauge goes between the shoe and the gauge arm without touching, extend the adjuster until it slides between them with some resistance.
14: The adjuster has a locking tang that engages the adjuster teeth and prevents the wheel from turning. To make an adjustment, push the tang back with a small flat-blade screw driver than use a larger screw driver to turn the adjuster.
15: With the hub flanges clean and the P-brake adjusted, the rotors go back on.
16: Brake caliper mounting bracket and brake caliper bolts must be torqued to 100-ft/lbs. Of late, we’ve switched from a dial torque wrench to one of Gear Wrench’s new, electronic torque wrenches. We like the increased leverage from its greater length and we like the aural warnings that you are approaching the desired torque and we like the haptic notification that the desired torque has been reached.
Servicing the 1997-2013 Corvette parking brake:C5/C6 Corvette Parking Brake
Text and images by Hib Halverson
Source: Zip Corvette Parts
8067 Fast Lane | Mechanicsville, VA 23111 | (800) 962-9632
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