2005 gmc envoy front pads won't release put on 2 new calipers,2 brake hoses,2 new rotors&pads.I forgot,put on new Master cylinder.changed calipers twice thought they might be defective.

Most likely a warped rotor and with new pads it has locked it's self up.

Check ur master cilinder , a way to know if your wheels are free, jack it up turn the wheel by hand if not realese the bleeder on top of the caliper and try again if it is free probably u need to replace master cil.

I had the same problem and replaced both calipers with no change, I figured it was the master cylinder. When I pulled off the master cylinder I saw the vacume booster had about 2 cups of brake fluid in it which leaked from the front of the master cylinder. I replaced master cylinder and vacume booster and brakes work great now.

Removal & Installation Front To Remove:

1. Inspect the fluid level in the master cylinder reservoir. Remove fluid from the reservoir until the level is lower then half way between the MAX and MIN levels.
2. Remove the tire and wheel assembly.
3. Install 2 wheel nuts to secure the rotor on the hub.
4. Remove the bottom brake caliper pin bolt.
5. Pivot the brake caliper body upward and secure out of the way. Do NOT disconnect the hydraulic brake flexible hose from the caliper.
6. Compress the piston back into the bore using a C-clamp. Figure of brake assembly with caliper raised showing brake pads in mounting bracket
   
   
7. Remove the inboard and outboard brake pads from the brake caliper bracket.

To Install:

1. Install the brake pad retainers and both brake pads into the caliper bracket.
2. Pivot the brake caliper down over the brake pads and into the brake caliper bracket. Insert the lower brake caliper pin bolt and torque bolt to 70 ft-lb. (95 Nm).
3. Reinstall the tire and wheel assembly.
4. Lower the vehicle.
5. Refill the master cylinder. Pump the brake pedal several times to seat the pads against the rotor.
6. Check the master cylinder level and add fluid as necessary.

Rear To Remove:
Rear disc pads R&I

1. Inspect the fluid level in the master cylinder reservoir. Remove fluid from the reservoir until the level is lower then half way between the MAX and MIN levels.
2. Remove the tire and wheel assembly.
3. Install 2 wheel nuts to secure the rotor on the hub.
4. Remove the upper caliper mounting bolt.
5. Pivot the caliper down to access the pads.
6. Remove the inboard and outboard pads from the caliper bracket.
7. Remove the brake pad clips from the caliper bracket.
8. Compress the piston back into the bore using a C-clamp and the old inner pad.

To Install:

1. Install new brake clips in the caliper bracket.
2. Install the inboard and outboard pads in the caliper bracket.
3. Pivot the caliper up over the pads.
4. Reinstall the upper mounting bolt and tighten to 32 ft. lbs. (44 Nm).
5. Remove the 2 wheel nuts securing the rotor.
6. Reinstall the tire and wheel assembly.
7. Refill the master cylinder. Pump the brake pedal several times to seat the pads against the rotor.
8. Check the master cylinder level and add fluid as necessary.

Disc Brake Pads for Suburban 1500 Removal & Installation Front To Remove:
Front caliper mounting bracket

1. Remove the cover on the master cylinder and siphon out 2/3 of the fluid. This step prevents spilling fluid when the piston is pushed back into the caliper bore.
2. Raise and support the vehicle safely.
3. Remove the wheel and tire assembly.
4. Compress the brake piston back into its bore using a C-clamp.
5. Remove the 2 caliper mounting bolts. Lift the caliper off the rotor.
6. Remove the inboard and outboard pad.
7. Remove and discard the anti-rattle clips.

To Install:
Caliper bracket sleeves

1. Thoroughly inspect, clean and lubricate all caliper slide points, bolts and hardware.
2. Install new anti-rattle clips.
3. Position the inboard and outboard pads into the support bracket
4. With the 2 pads in position, place the caliper over the brake rotor and align the holes in the caliper with those of the mounting bracket.
5. Install the caliper mounting bolts through the sleeves in the inboard caliper ears and into the mounting bracket.
6. Tighten the mounting bolts to: 80 lb. ft, (110 Nm).
7. Install the tire and wheel assembly. Lower the vehicle.
8. Add fluid to the master cylinder reservoirs so they are 1/4 in. (6.35mm) from the top.
9. Test the brake pedal by pumping it to obtain a hard pedal. Check the fluid level and add fluid as necessary.

Rear To Remove:

1. Remove 2/3 of the brake fluid from the master cylinder.
2. Raise and safely support the vehicle.
3. Remove the wheel and tire assembly.
4. Remove the brake caliper mounting bolts. Suspend the caliper from the frame with mechanic's wire. Do not allow the caliper to hang from the brake hose.
5. Remove the brake pads from the caliper mounting bracket.
6. Remove and discard the anti-rattle clips.

Rear brake caliper

To Install:

1. Install new anti-rattle clips.
2. Position the brake pads to the caliper mounting bracket.
3. With the 2 pads in position, place the caliper over the brake rotor and align the holes in the caliper with those of the mounting bracket.
4. Install NEW caliper mounting bolts. Tighten to: 30 lb. ft, (40 Nm).
5. Install the wheel and tire assembly.
6. Lower the vehicle.
7. Refill the master cylinder to the proper level with fresh brake fluid. Pump the brake pedal slowly and firmly to seat the brake pads. Burnish the brakes as needed.

YOU NEED REMOVE A LITTLE BRAKE FLUID FROM MASTER CYLINDER.THEN YOU RAISE VECHICLE SAFELY.SUPPORT IT WITH JACK STAND.MAKE SURE VECHICLE IS ON LEVEL SOLID GROUND.REMOVE TIRE OR WHEEL.THEN YOU NEED A LARGE C - CLAMP.PLACE C - CLAMP OVER BRAKE CALIPER AND BRAKE SHOE BACKING.TIGHTEN C - CLAMP JUST ENOUGH PUSH CALIPER PISTON BACK IN CYLINDER BORE TO REMOVE CALIPERS FROM ROTORS.TO REMOVE BRAKE CALIPER YOU NEED 2 OPEN AND BOX END WRENCHES ONE TO HOLD CALIPER SLIDE PINS AND THE OTHER WRENCH FOR LOOSEN CALIPER BOLTS.THEN YOU REMOVE CALIPER AND REPLACE FRONT BRAKE SHOES.IF YOU NEED TO REMOVE BRAKE ROTORS JUST REMOVE THE BRAKE CALIPER CARRIER SUPPORT BOLTS THE REMOVE THE BRAKE CALIPER CARRIER SUPPORT THEN REMOVE ROTOR.YOU NEED TO REPLACE BOLTS WITH NEWS AND USE LOCK TIGHT.THEN YOU PUT IN NEW BRAKE PADS IN CALIPER PUT CALIPER BACK ON SUPPORT CARRIER.REPLACE WITH NEW BOLTS USE LOCK TIGHT THEN TORQUE BOLTS TO 26 FT LBS.MAKE SURE MASTER CYLINDER COVER IN PLACE.WHEN YOU FINISH REPLACING BOTH FRONT BRAKE PADS PUMP BRAKE PEDAL TO SEAT BRAKE SHOES AGAINST BRAKE ROTORS SO YOU WILL HAVE FIRM BRAKES WHEN YOU APPLY THEM. THEN CHECK YOUR BRAKE FLUID LEVEL IN MASTER CYLINDER MAKE SURE ITS NOT LOW. MAKE SURE YOU HAVE FIRM BRAKES BEFORE DRIVING.IF YOU HAVE ANY PROBLEMS CHANGING FRONT BRAKE PADS YOU CAN GO TO ANY AUTO PARTS STORE AND BUY A HAYNES REPAIR MANUAL.

Remove brake fluid from the master cylinder brake fluid reservoir until the reservoir is approximately 1/2 full. Discard the removed fluid.

1. Raise and safely support the front of the vehicle. Remove the front wheels.
   

1. Remove or disconnect the following:
2. Front brake caliper guide pin bolts
   

• Brake caliper by slowly sliding it up and off the adapter and brake rotor. Support the caliper out of the way with a strong piece of wire. Do not let the caliper hang by the brake hose or damage to the brake hose will result.
  

1. If necessary, compress the caliper piston into the bore using a C-clamp. Insert a suitable piece of wood between the C-clamp and caliper piston to protect the piston.
2. Outboard disc brake pad from the caliper by prying the brake pad retaining clip over the raised area on the caliper. Slide the brake pad down and off the caliper.
   

• Inboard disc brake pad from the caliper by pulling the brake pad away from the caliper piston until the retaining clip on the pad is free from the caliper piston cavity
  

To install:

1. Be sure the caliper piston has been completely retracted into the piston bore of the caliper assembly. This is required when installing the brake caliper equipped with new brake pads.
   
2. If equipped, remove the protective paper from the noise suppression gaskets on the new disc brake pads.
   
3. Install or connect the following:
   
   • New inboard disc brake pad into the caliper piston by pressing the pad firmly into the cavity of the caliper piston. Be sure the new inboard brake pad is seated squarely against the face of the brake caliper piston.
     
   • Outboard disc brake pad by sliding it onto the caliper assembly
     
   • Brake caliper assembly over the brake rotor and onto the steering knuckle adapter
     
   • Caliper guide pin bolts and torque to: 35 ft. lbs. (47 Nm) on 2002–04 models or 26 ft. lbs. (35 Nm) on 2005 models
     
   • Front. Apply the brake pedal several times until a firm pedal is obtained.
     
4. Check the fluid level in the master cylinder and add fluid as necessary. Road-test the vehicle.
   

For the rotors:

1. Remove brake fluid from the master cylinder brake fluid reservoir until the reservoir is approximately 1/2 full. Discard the removed fluid.
   
2. Raise and safely support the front of the vehicle. Remove the front wheels.
   

1. Remove or disconnect the following:
2. Front brake caliper guide pin bolts
   

• Brake caliper by slowly sliding it up and off the adapter and brake rotor. Support the caliper out of the way with a strong piece of wire. Do not let the caliper hang by the brake hose or damage to the brake hose will result.
  

1. If necessary, compress the caliper piston into the bore using a C-clamp. Insert a suitable piece of wood between the C-clamp and caliper piston to protect the piston.
2. Outboard disc brake pad from the caliper by prying the brake pad retaining clip over the raised area on the caliper. Slide the brake pad down and off the caliper.
   

• Inboard disc brake pad from the caliper by pulling the brake pad away from the caliper piston until the retaining clip on the pad is free from the caliper piston cavity
  

To install:

1. Be sure the caliper piston has been completely retracted into the piston bore of the caliper assembly. This is required when installing the brake caliper equipped with new brake pads.
   
2. If equipped, remove the protective paper from the noise suppression gaskets on the new disc brake pads.
   
3. Install or connect the following:
   
   • New inboard disc brake pad into the caliper piston by pressing the pad firmly into the cavity of the caliper piston. Be sure the new inboard brake pad is seated squarely against the face of the brake caliper piston.
     
   • Outboard disc brake pad by sliding it onto the caliper assembly
     
   • Brake caliper assembly over the brake rotor and onto the steering knuckle adapter
     
   • Caliper guide pin bolts and torque to: 35 ft. lbs. (47 Nm) on 2002–04 models or 26 ft. lbs. (35 Nm) on 2005 models
     
   • Front. Apply the brake pedal several times until a firm pedal is obtained.
     
4. Check the fluid level in the master cylinder and add fluid as necessary. Road-test the vehicle.
   

find out what tool you need to remove bolts for the caliper(2) once you get the bolts out remove caliper. next step remove old pads.then you will need a c clamp to compress piston on the caliper back in then get new pads and install them on caliper easy fix reinstall caliper on to rotor and put bolts back in just observe how the caliper came off

on the wheel that is hot, jack it up and see it the wheel spins free or drags? if it drags, then loosen bleeder on the caliper, it if now spins free, you want to replace that caliper hose, if it is still dragging, then the caliper piston is stuck and you will need to replace it.

Replace brake hoses,they have an inner core that has ruptured and the outside rubber core is keeping pressure on the caliper with you foot off the brake. This will fix it! A common problem for this vehicle.