Can`t open rear brake caliper - A6 Audi Cars & Trucks

Replace caliper with old brake pads put 1 bolt in place to hold together while taking a large screwdriver and prying caliper piston so that it compresses piston & block wedge to rear of bracket it should make enough room to install on new brake pads, the other way is to use a large c clamp put 1/4 pice of wood in between c clamp and caliper so you don't damage or Mar the caliper also check YouTube.

Remove the caliper mounting bolts and remove the caliper. Replace brake pads as necessary. Special tool is required to retract caliper piston to fit over new pads. (see picture below)
Retract piston in caliper using special tool to rotate clockwise and make sure the notch in the piston is aligned properly so the tab on the inner pad will fit in properly.
Reinstall caliper assembly and caliper mounting bolts.

try to get it overhauled..because might be it has gone jammed due to dust clottings......else get it replaced due to severe risks of brakes jams

Brake Pads Removal & Installation Front To Remove:

1. Remove the front wheels. Front brake caliper (exploded view)
   
   
2. Loosen the caliper bleeder.
3. Hold the slide pin; remove the 2 mounting bolts and remove the brake caliper from the support.
4. Support the caliper.
5. Open the brake bleeder. Press the caliper piston into the bore.
6. Close the bleeder after the piston has reached the bottom of the caliper bore.
7. Remove the brake pads, support plates, wear indicators and anti squeal shims.
8. Remove the slide pins and bushings from the caliper support.

To Install:

1. Lubricate the slide pins and bushings with brake grease.
2. Install the bushing on the slide pin.
3. Install the slide pin on the caliper support.
4. Install the brake pad support plates on the caliper supports.
5. Lubricate the anti squeal shims with brake grease.
6. Install the anti squeal shims on the brake pads.
7. Install the pad wear indicator facing upward and install the pads on the caliper support.
8. Install the caliper on the support.
9. Install the 2 mounting bolts, hold the slide pins and tighten 25 ft-lb (34 Nm).
10. Fill the reservoir and bleed the brakes.
11. Install the front wheels.

Rear To Remove:

1. Remove the rear wheels.
2. Loosen the caliper bleeder. Rear brake caliper (exploded view)
   
   
3. Hold the slide pin; remove the 2 mounting bolts and rear brake caliper assembly from the support.
4. Support the caliper.
5. Open the brake bleeder. Press the caliper piston into the bore.
6. Close the bleeder after the piston has reached the bottom of the caliper bore.
7. Remove the brake pads, support plates, and anti squeal shims.
8. Remove the slide pins from the caliper support.

To Install:

1. Lubricate the slide pins with brake grease.
2. Install the slide pin on the caliper support.
3. Install the brake pad support plates on the caliper supports.
4. Lubricate the anti squeal shims with brake grease.
5. Install the anti squeal shims on the brake pads.
6. Install the rear pads on the caliper support.
7. Install the rear caliper on the support.
8. Install the 2 mounting bolts, hold the slide pins and tighten 25 ft-lb (34 Nm).
9. Fill the reservoir and bleed the brakes.
10. Install the front wheels.

Rear disc brake pads offer better performance and are not as affected by moisture like conventional brake shoe style brakes are. Rear disc brakes are similar to front disc brakes. The main difference is that rear disc brake systems must incorporate the emergency brake system. There are two methods widely used for the emergency brake with rear disc systems. The first system is a brake shoe inside the brake disc that is actuated by the emergency brake lever. The second is a screw style actuator inside the brake caliper. When activated the brake pads are forced into the brake disc and held tightly by the emergency brake lever.
READ COMPLETELY BEFORE STARTING
Step 1 - Identify Rear Disc Brake Components
Rear disc brake assembly includes; rear brake disc, rear brake pads, brake caliper mount and a caliper mounting screw. (Note: Some vehicles do not have the rotor mounting screw.)
Step 2 - Removing the Rear Brake Caliper Mount Bolts
To replace rear brake pads and rotors the rear brake caliper needs to be removed. First loosen the rear brake caliper mount bolts and remove them. Turn counter clockwise.
Step 3 - Lift Rear Brake Caliper from The Caliper Mount
After the caliper mount bolts have been removed, gently lift the brake caliper from the caliper mount. Inspect the caliper slides; they should move freely in the caliper mount. Remove rear brake pads and hardware.

Step 4 - Removing Caliper Mount Bolts
With a socket wrench or other appropriate removal tool, loosen the rear brake caliper mounting bolts. Remove bolts and lift the caliper mount and remove it from the vehicle. Remove the retaining screw from the disc mounting hole. Tap the rotor gently to release any rust that has accumulated between the rotor and bearing hub. Lift brake rotor from wheel hub holding on tightly, using both hands. You do not want to drop the rotor.

Step 5 - Removing Rear Brake Rotor
Remove the retaining screw from the disc mounting hole, tap the rotor gently to release any rust that has accumulated between the rotor and bearing hub. Lift brake rotor from wheel hub, hold on using both hands and do not drop.

Step 6 - Install New Brake Rotor
Check the new rotor against the old brake rotor to make sure they are the same size. Clean the mating surface on the wheel hub before the new brake rotor is installed. Reinstall rotor retainer screw.
Step 7 - Reset Rear Brake Caliper
Before new brake pads can be installed, the rear brake caliper must be reset. The reset tool winds the piston back into position so the new brake pads will fit. This style of brake caliper will not compress with a clamp tool; it can only be reset with the proper reset tool.
Step 8 - Reinstall Rear Caliper Mount and Install New Rear Brake Pads
After the caliper has been reset, reinstall caliper mounting bolts and make sure the bolts are tight. Then match up the old brake pads to the new brake pads. They should be exactly the same except, of course; the old ones will be worn out. Check the new brake pads for proper fit and install any brake hardware that is required.
Step 9 - Remount Rear Brake Caliper
Reinstall the brake caliper, align brake pad hardware and reinstall caliper mounting bolts. (Note: align the rear peg of the brake pad to the groove in the caliper piston.) Recheck and retighten all caliper and caliper mount bolts. Bleed brake system to relieve any air in the system. Before driving the vehicle, push the brake pedal down and let it up slowly. This operation forces the brake pads to travel to the brake rotors. DO NOT DRIVE VEHICLE until proper brake pedal operation resumes. When test driving vehicle listen for any unusual noises during the operation of the brakes.
WARNING! Always have the vehicle under inspection on level ground, in park with the emergency brake on. Always wear protective eyewear, gloves and necessary clothing before inspection or work begins. Never crank an engine over when anyone is near the battery or engine. Always have an operational fire extinguisher close by, obey all first aid instructions in the event of an injury. Never stand in front or behind a vehicle when cranked over or running. When engine is cranked over keep hands and clothing away from rotating components. Never move a car without proper brake pedal operation.

Caliper removal

1. Disconnect the brake hose.
2. Remove the bolt.
3. Disconnect the rear wheel brake hose (2A442).
4. Remove the copper washers and plug the brake hose.

1. CAUTION: Do not remove the guide pins or guide pin boots unless a problem is suspected. The guide pins are meant to be sealed for life and are not repairable. Use Silicone Brake Caliper Grease and Dielectric Compound D7AZ-19A331-A (Motorcraft WA-10) or an equivalent silicone compound meeting Ford specification ESE-M1C171-A for re-lubing the caliper slide pins. Other greases can swell the guide pin boots, resulting in contamination and accelerated corrosion or wear of the caliper slide pin mechanism.
   Remove the rear disc brake caliper (2552).
   1. Remove the brake caliper bolts (2W303).
   1. Lift the rear disc brake caliper off the rear disc brake caliper anchor plate (2C220).

1. Inspect the rear disc brake caliper for leaks.
• If leaks are found, disassembly is required. Refer to Caliper in this section.

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Disc Removal and Installation

1. NOTE: When removing the rear brake disc (2C026) in this procedure it is not necessary to disconnect the hydraulic lines.
   Remove the rear disc brake caliper (2552). For additional information, refer to Caliper in this section.

1. NOTE: If the rear brake disc binds on the rear parking brake shoe and linings, remove the adjustment hole access plug and retract the parking brake shoe and lining.
   Remove the rear brake disc.

1. CAUTION: Use a hub-mount brake lathe if necessary to machine the rear brake disc. For additional information on machining brake discs, refer to Section 206-00 .
   Measure the rear brake disc, and resurface as necessary. Install a new rear brake disc if beyond specification.

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Installation

1. CAUTION: To prevent interference with rear disc brake caliper operation, install only the correct caliper bolt.
   NOTE: Make sure the stainless steel shoe slippers are correctly positioned. Install new slippers if worn or damaged.
   NOTE: When installed, the locator notch on the brake pads will be located at the upper end of the rear disc brake caliper.
   Install the rear disc brake caliper.

1. Install the rear wheel brake hose.
   • Connect the brake hose and install the caliper flow bolt.
     • Use new copper washers.

1. Bleed the disc brake caliper. For additional information, refer to Section 206-00 .

1. Install the wheel and tire assembly. For additional information, refer to Section 204-04 .

1. Verify correct brake operation.

Per Chilton Auto repair manual:

Removal & Installation

1. Raise and safely support the vehicle.
   
2. Remove the rear wheel.
   
3. Siphon a small amount of brake fluid from the master cylinder reservoir.
   
4. Insert a small prybar through the caliper opening and pry the caliper cover (using the outboard brake pad) to bottom the piston in the caliper bore.
   
5. Remove the caliper slide bolts.
   
6. Remove the caliper from the anchor.
   
   WARNING Support the brake caliper with mechanics wire. Do not let the caliper hang by the brake hose.
   
7. Remove the brake pads from the caliper.
   

To install:

1. Install the brake pads onto the caliper.
   
2. Lubricate the slide pin bolts with grease provided with the brake pads, or suitable silicon grease equivalent.
   
3. Install the caliper on the anchor and tighten the slide pin bolts to 18 ft. lbs. (25 Nm).
   
4. Install the rear wheel.
   
5. Lower the vehicle.
   
6. Pump the brake pedal several times until a firm pedal is obtained in order to properly seat the pads.
   
7. Refill the brake fluid reservoir to the proper level.
   

1. Disconnect the brake hose.
2. Remove bolt.
3. Disconnect the rear wheel brake hose (2A442).
4. Remove the copper washers and plug the brake hose.
Disconnect the brake hose.
1. Remove bolt.
1. Disconnect the rear wheel brake hose (2A442).
1. Remove the copper washers and plug the brake hose.
1. CAUTION: Do not remove the guide pins or guide pin boots unless a problem is suspected. The guide pins are meant to be sealed for life and are not repairable. Use Silicone Brake Caliper Grease and Dielectric Compound D7AZ-19A331-A (Motorcraft WA-10) or an equivalent silicone compound meeting Ford specification ESE-M1C171-A for re-lubing the caliper slide pins. Other greases can swell the guide pin boots, resulting in contamination and accelerated corrosion or wear of the caliper slide pin mechanism.
   Remove the rear disc brake caliper (2552).
   1. Remove the brake caliper bolts (2W303).
   1. Lift the rear disc brake caliper off the rear disc brake caliper anchor plate (2C220).
1. Inspect the rear disc brake caliper for leaks.
   • If leaks are found, disassembly is required. Refer to Caliper in this section.
Installation

1. CAUTION: To prevent interference with rear disc brake caliper operation, install only the correct caliper bolt.
   NOTE: Make sure the stainless steel shoe slippers are correctly positioned. Install new slippers if worn or damaged.
   NOTE: When installed, the locator notch on the brake pads will be located at the upper end of the rear disc brake caliper.
   Install the rear disc brake caliper.
1. Install the rear wheel brake hose.
   • Connect the brake hose and install the caliper flow bolt.
     • Use new copper washers.
1. Bleed the disc brake caliper. For additional information, refer to Section 206-00 .
1. NOTE: If equipped with air suspension, reactivate the system by turning on the air suspension switch.
   Install the wheel and tire assembly. For additional information, refer to Section 204-04 .
1. Verify correct brake operation.
5. CAUTION: Do not remove the guide pins or guide pin boots unless a problem is suspected. The guide pins are meant to be sealed for life and are not repairable. Use Silicone Brake Caliper Grease and Dielectric Compound D7AZ-19A331-A (Motorcraft WA-10) or an equivalent silicone compound meeting Ford specification ESE-M1C171-A for re-lubing the caliper slide pins. Other greases can swell the guide pin boots, resulting in contamination and accelerated corrosion or wear of the caliper slide pin mechanism.
   Remove the rear disc brake caliper (2552).
   1. Remove the brake caliper bolts (2W303).
   1. Lift the rear disc brake caliper off the rear disc brake caliper anchor plate (2C220).

1. Inspect the rear disc brake caliper for leaks.
• If leaks are found, disassembly is required. Refer to Caliper in this section.

Disc Removal

1. NOTE: When removing the rear brake disc (2C026) in this procedure it is not necessary to disconnect the hydraulic lines.
   Remove the rear disc brake caliper (2552). For additional information, refer to Caliper in this section.

1. NOTE: If the rear brake disc binds on the rear parking brake shoe and linings, remove the adjustment hole access plug and contract the parking brake shoe and lining.
   Remove the rear brake disc.

1. CAUTION: Use a hub-mount brake lathe if necessary to machine the rear brake disc.
   Measure the rear brake disc, and resurface as necessary. Install a new rear brake disc if beyond specification.

--------------------------------
Installation

1. CAUTION: To prevent interference with rear disc brake caliper operation, install only the correct caliper bolt.
   NOTE: Make sure the stainless steel shoe slippers are correctly positioned. Install new slippers if worn or damaged.
   NOTE: When installed, the locator notch on the brake pads will be located at the upper end of the rear disc brake caliper.
   Install the rear disc brake caliper.

1. Install the rear wheel brake hose.
   • Connect the brake hose and install the caliper flow bolt.
     • Use new copper washers.

1. Bleed the disc brake caliper. For additional information, refer to Section 206-00 .

1. NOTE: If equipped with air suspension, reactivate the system by turning on the air suspension switch.
   Install the wheel and tire assembly. For additional information, refer to Section 204-04 .

1. Verify correct brake operation.

206-04: Rear Disc Brake 2000 Explorer/Mountaineer Workshop Manual REMOVAL AND INSTALLATION Disc Removal

1. NOTE: When removing the rear brake disc (2C026) in this procedure it is not necessary to disconnect the hydraulic lines.
   Remove the rear disc brake caliper (2552). For additional information, refer to Caliper in this section.
2. Disconnect the brake hose.
3. Remove bolt.
4. Disconnect the rear wheel brake hose (2A442).
5. Remove the copper washers and plug the brake hose.

1. CAUTION: Do not remove the guide pins or guide pin boots unless a problem is suspected. The guide pins are meant to be sealed for life and are not repairable. Use Silicone Brake Caliper Grease and Dielectric Compound D7AZ-19A331-A (Motorcraft WA-10) or an equivalent silicone compound meeting Ford specification ESE-M1C171-A for re-lubing the caliper slide pins. Other greases can swell the guide pin boots, resulting in contamination and accelerated corrosion or wear of the caliper slide pin mechanism.
   Remove the rear disc brake caliper (2552).
   1. Remove the brake caliper bolts (2W303).
   1. Lift the rear disc brake caliper off the rear disc brake caliper anchor plate (2C220).

1. Inspect the rear disc brake caliper for leaks.
   • If leaks are found, disassembly is required. Refer to Caliper in this section.

1. NOTE: If the rear brake disc binds on the rear parking brake shoe and linings, remove the adjustment hole access plug and contract the parking brake shoe and lining.
   Remove the rear brake disc.

1. CAUTION: Use a hub-mount brake lathe if necessary to machine the rear brake disc.
   Measure the rear brake disc, and resurface as necessary. Install a new rear brake disc if beyond specification.

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1. Remove the rear disc brake caliper (2K327).
2. Remove the brake caliper bolts.
3. Lift the rear disc brake caliper off the rear disc brake caliper anchor plate (2B582).

1. CAUTION: Do not allow grease, oil, brake fluid or other contaminants to contact the brake pads.
   Remove the brake pads by pushing inward and rotating the pad up.

1. NOTE: Use a block of wood or used pad to protect the piston and boots.
   Retract the caliper piston (2196) into the rear disc brake caliper.