Rear break drum wont go back on after changing shoes. the adjuster is in all of the way, everything is assembled correctly and I squeezed the brakes together. they are self adjusting.

The brake drum does not fit due to the pressure in brake cylinders. Some of the cylinders are designed to keep a little pressure on, even when the pedal is released. The reason is that you will have instant reaction on pushing break pedal because there is no free space between drum and pads. You need to take clamp and push the pistons back in cylinder, but only that much so you can fit the drum. After the drum is tightened you must pump the brake pedal until you can fell that there is no free fall. The hand brake should be ok, but check it just to be shore. If there is need to tension the cable, it can be done under lever from outside the car (you must go under the car).

Removal
1.Remove rear wheel and tire assembly from vehicle.

2.Remove rear brake drums from hub and bearing assemblies after loosening the two brake drum screws.

3.Be sure that the parking brake pedal is in the release(most upward) position.

4.Completely loosen square nut of the rear parking brake cable. Then create slack in the rear parking brake cables.

5.Remove adjuster spring from adjust lever and brake shoe.

6.Remove adjust lever and turn the adjusting wheel of adjuster assembly to the direction of the arrow as shown.

7.Remove the strut spring and the lower retracting spring from the brake shoe.

8.Remove the upper return spring from the brake shoe.

9.Remove brake back plate hold down spring and pin from the leading brake shoe assembly.

10.Remove the leading brake shoe. Then remove the adjuster assembly, strut and anchor spring from the trailing brake shoe.

11.Remove the trailing brake shoe from the brake back plate after removing hold down spring and pin.

12.Remove the trailing brake shoe from the rear parking cable.

13.Remove parking pivot lever from the leading brake shoe.

Replacement
1.Lubricate the eight shoe contact areas on the back plate and anchor.

2.Install the trailing brake shoe to the rear parking cable.

3.Install trailing brake shoe on brake back plate and install the trailing brake shoe hold down spring and pin on the brake shoe.

4.Tighten the square nut of rear parking cable.

5.Install the anchor spring then install adjuster assembly, and strut.

6.Install leading brake shoe on brake back plate.

7.Install the brake shoe upper return spring, strut spring and the lower retracting spring to the brake shoe.

8.Properly rotate the adjusting wheel of adjuster assembly to the direction of the arrow in as shown.

9.Install the adjuster spring on the adjust lever and leading brake shoe assembly.

10.Install the leading brake shoe hold down spring and pin on the brake shoe.

11.Adjust brake shoes assemblies so as not to interfere with brake drum installation.

12.Install the rear brake drums on the hubs.

13.Check and adjust whether the pedal stroke in the specification.(Refer to section BR Gr./On-vehicle service/Pedal stroke of parking brake)

14.Install wheel and tire.

15.Push the parking brake pedal to the floor once and release pedal. This will automatically remove the slack from and correctly adjust the parking brake cables.

16.Test the vehiche on the road. The adjust will continue the brake adjustment during the road test of vehicle.

Inspection
1.Inspect the disassembled parts for wear, rust or damage.

2.Measure the thickness of brake shoe lining.
Standard : 0.17 in (4.5 mm)
Minimum : 0.04 in (1 mm)

3.If the shoe lining is less than minimum or shows signs of uneven wear, replace new one.

4.Measure the inside diameter of the brake drum.
Standard : 10 in (254 mm)
Maximum : 10.07 in (256 mm)

5.If the inside diameter of the brake drum is more than maximum or shows signs of uneven wear, replace new one.

6.Inspect the lining and drum for proper contact. If the contact condition is improper, repair it with a grinder or replace the brake shoe assembly.

No, just back off the adjusters completely before putting on the drums.

REMOVAL & INSTALLATION
It is a good idea to only disassemble and assemble one side at a time, leaving the other side intact as a reference.

1. Raise and support the vehicle safely.
2. Remove the brake drum.
3. Disconnect the parking brake rear cable and conduit.
4. Remove the brake shoe hold-down springs and brake shoe hold-down pins.
5. Remove the brake shoe adjusting screw spring.
6. Remove the brake shoe adjusting lever and adjuster screw.
7. Remove the brake shoe retracting spring.
8. Remove the brake shoes from the backing plate.
9. Remove and discard the parking brake lever clip. Remove the washer.
10. Remove the parking brake lever from the rear brake shoe.

To install:

1. Thoroughly clean the backing plate with brake cleaning solvent and dry completely.
2. Use silicone grease to lubricate the brake backing plate-to-brake shoe contact areas.
3. Apply a light coating of premium grease to the threaded areas of the adjuster. Turn the adjuster in and out to spread the lubricant. Turn the adjuster all the way down on the screw and loosen one-half turn.
4. Install the parking brake lever to the rear (secondary) brake shoe with a new clip.
5. Position the brake shoes on the backing plate and install the brake shoe hold-down springs.
6. Attach the parking brake rear cable and conduit to the parking brake lever.
7. Attach the brake shoe retracting spring.

The socket end of the brake adjuster screw is stamped with "R" or "L" to indicate that it is to be installed either on the right (passenger's side) or left (driver's side) of the vehicle. The adjuster nuts can be distinguished by the number of grooves machined around the body of the nut. Two grooves indicate a right-hand adjuster nut and one groove indicates a left-hand adjuster nut. Another way to identify brake adjuster assemblies is to check thread pitch. The right side adjuster assembly has right-hand threads and the left side has left-hand threads. If installed correctly, the brake adjuster assembly will increase in length when the brake shoe adjusting lever is operated.

1. Install brake adjuster screw in the slots on the brake shoes. The wider slot on the socket end must fit in the slot on the front (primary) brake shoe.
2. Install the brake shoe adjusting lever on the lever pin.
3. Install the brake adjusting screw in the slot on the secondary brake shoe and in the slot on the brake shoe lever. The brake shoe adjusting lever should contact the brake adjuster screw.
4. Adjust the brake shoes.
5. Install the drums.

ADJUSTMENTS

The drum brakes are self-adjusting and require a manual adjustment only after the brake shoes have been replaced, or when the length of the adjusting screw has been changed while performing some other service operation.
Drum Installed

1. Raise and support the vehicle safely.
2. Remove the rubber plug from the adjusting slot on the backing plate.
3. Insert a Brake Adjustment Tool (D81L-1103-C) or equivalent into the slot and engage the lowest possible tooth on the starwheel. Move the end of the brake spoon downward to move the starwheel upward and expand the adjusting screw. Repeat this operation until the brakes lock the wheels.
4. Insert a small screwdriver or piece of firm wire (coat hanger wire) into the adjusting slot and push the automatic adjusting lever out and free of the starwheel on the adjusting screw and hold it there.
5. Engage the topmost tooth possible on the starwheel with the brake adjusting spoon. Move the end of the adjusting spoon upward to move the adjusting screw starwheel downward and contract the adjusting screw. Back off the adjusting screw starwheel until the wheel spins freely with a minimum of drag. Keep track of the number of turns that the starwheel is backed off, or the number of strokes taken with the brake adjusting spoon.
6. Repeat this operation for the other side. When backing off the brakes on the other side, the starwheel adjuster must be backed off the same number of turns to prevent side-to-side brake pull.
7. When the brakes are adjusted, make several stops while backing the vehicle to equalize the brakes on both of the wheels.
8. Lower the vehicle.

Drum Removed
See Figure 2

Fig. Fig. 2: When using a brake adjustment gauge, first measure the inside diameter of the drum (top) and then adjust the brakes shoes to the proper outside diameter (bottom)

1. Remove the brake drum.
2. Make sure that the shoe-to-contact pad areas are clean and properly lubricated.
3. Using a Brake Adjustment Gauge (D81L-1103-A) or equivalent, check the inside diameter of the drum.
4. Measure across the diameter of the assembled brake shoes, at their widest point.
5. Turn the adjusting screw so that the diameter of the shoes is 0.030 in. (0.76mm) less than the brake drum inner diameter.
6. Install the drum.

INSPECTION

See Figure 3

Fig. Fig. 3: Measure brake shoe thickness in several places around the shoe
Inspect the brake shoes for wear using a ruler or Vernier caliper. Compare measurements to the brake specifications chart. If the lining is thinner than specification or there is evidence of the lining being contaminated by brake fluid or oil, replace all brake pad assemblies (a complete axle set).

1989-97 Vehicles Drum Brakes (Let me know if you need the Disc Brake Instructions)

1. Raise and safely support the vehicle.
   
2. Remove the rear wheel and tire assemblies, then remove the brake drum.
   
   
   
   
   
   Fig. 4: View of the drum brake assembly with the drum removed
   
   
   
   
   
   
   Fig. 5: Use a commercially available brake spray to clean the
   components before removal
   
   
   
   
3. Install Brake Cylinder Clamp D81L-1103-B or equivalent, over the ends of the
   rear wheel cylinder.
   
4. Disconnect the parking brake cable from the parking brake lever.
   
   
   
   
   
   Fig. 6: Detach the parking brake cable and conduit from the
   parking brake lever
   
   
   
   
5. Remove the 2 brake shoe hold-down retainers, springs and pins.
   
6. Spread the brake shoes over the piston shoe guide slots. Lift the brake
   shoes, springs and adjuster off the backing plate as an assembly. Be careful not
   to bend the adjusting lever.
   
   
   
   
   
   Fig. 7: Lift the brake shoes, springs and adjuster off the
   backing plate as an assembly
   
   
   
   
7. Remove the adjuster spring. To separate the shoes, remove the retracting
   springs.
   
8. Remove the parking brake lever retaining clip and spring washer. Remove the
   lever from the pin.
   
   
   
   
   
   Fig. 8: Drum brake components - 1995 vehicle shown
   
   
   
   
   
   
   
   Fig. 9: Exploded view of the drum brake components, removed
   from the vehicle
   
   To install:
   
   
9. Apply a light coating of caliper slide grease to the backing plate brake
   shoe contact areas.
   
10. Apply a light coat of lubricant to the threaded areas of the adjuster screw
    and socket. Assemble the brake adjuster with the stainless steel washer. Turn
    the socket all the way down on the screw, then back off 1?2 turn.
    
11. Install the parking brake lever to the trailing shoe with the spring washer
    and a new retaining clip. Crimp the clip to securely retain the lever.
    
12. Position the trailing shoe on the backing plate and attach the parking brake
    cable. Position the leading shoe on the backing plate and attach the lower
    retracting spring to the brake shoes.
    
13. Install the adjuster assembly to the slots in the brake shoes. The socket
    end must fit into the wider slot in the leading shoe. The slot in the adjuster
    nut must fit into the slots in the trailing shoe and parking brake lever.
    
    
    
    
    
    Fig. 10: Install the adjuster assembly in the slots in the
    brake shoes
    
    
    
    
    
14. Install the adjuster lever on the pin on the leading shoe and to the slot in
    the adjuster socket.
    
15. Install the upper retracting spring in the slot on the trailing shoe and the
    slot in the adjuster lever. The adjuster lever should contact the star and
    adjuster assembly.
    
16. Install the brake shoe anchor pins, springs and retainers. Remove the brake
    cylinder clamp tool
    
17. Install the brake drum, wheel and tire assemblies and lower the vehicle.
    
18. Apply the brakes several times while backing up the vehicle. After each
    stop, the vehicle must be moved forward.
    
    

You will need to loosen the bleeder valve and push in on both sides of the brake pistons that hold the shoes apart. This will give you enough clearance. Also measure along outside edges to make sure the brake shoes are centered in the opening and make sure nobody applied the parking break after the procedure was started. Make sure to tighten bleeder valve afterwards, have someone press on brake and release brake fluidd through hose into clean brake fluid covered hose end in a bottle to bleed the brakes and keep doing this cycle until all bubbles are gone or pedal will be soft. You can read up online about bleeding brakes for tips and full instructions.

Brake Shoes Removal & Installation Duo-Servo Type To Remove:

1. Raise the vehicle and support it safely.
2. Remove the tire and wheel assembly.
3. Remove the brake drums.
4. Using a brake tool, remove the shoe return springs.
5. Remove the shoe guide.
6. Remove the hold-down springs and pins.
7. Remove the actuator lever and pivot.
8. Remove the lever return spring.
9. Remove the actuator link, parking brake strut, spring retaining ring.
10. Remove the parking brake lever and washer.
11. Remove the shoe assemblies.
12. Remove the adjuster screw and spring from the shoe assembly.

To Install:

1. Use brake cleaning fluid to remove dirt from the brake drum. Check the drums for scoring, cracks and for out-of-round; service the drums as necessary.
2. Check the wheel cylinders by carefully pulling the lower edges of the wheel cylinder boots away from the cylinders. If there is excessive leakage, the inside of the cylinder will drip fluid; repair or replace as necessary.
3. Check the flange plate, which is located around the axle, for leakage of differential lubricant.
4. Lightly lubricate the parking brake cable, parking brake lever where it enters the shoe and the backing plate-to-shoe contact points. Use high temperature, waterproof, grease or special brake lube.
5. Install the parking brake lever into the secondary shoe with the attaching bolt, spring washer, lockwasher, and nut. It is important that the lever move freely before the shoe is attached. Move the assembly and check for proper action.
6. Lubricate the adjusting screw and make sure it works freely.
7. Connect the adjuster screw and spring to the bottom portion of both shoes. Ensure the spring does not interfere with the adjuster rotation when installed. The primary (smaller shoe pad area) to the front and secondary shoe (larger shoe pad area) to the rear of the vehicle.
8. Install the shoe assembly. Ensuring the shoe webs are positioned correctly against the wheel cylinder.
9. Install the parking brake cable.
10. Secure the primary shoes with the hold-down pin and spring.
11. Install the parking brake strut and the strut spring.
12. Install the actuator lever and pivot, securing the assembly with the hold-down pin and spring. Install the actuator link and spring.
13. Install the return springs.
14. Check the operation of the self-adjusting mechanism by moving the actuating lever by hand.
15. Adjust the brakes and install the drum.
16. Adjust the parking brake.
17. Install the tire and wheel assembly.
18. Lower the vehicle.

Leading-Trailing Type To Remove:

1. Raise the vehicle and support it safely.
2. Remove the tire and wheel assembly.
3. Remove the brake drums.
4. Raise the lever arm of the actuator until the upper end is clear of the slot in the adjuster screw.
5. Slide the actuator off the adjuster pin. Disconnect the actuator spring from the shoe.
6. Remove the hold-down spring assemblies and pins.
7. Pull the bottom ends of the shoes apart and lift the lower return spring over the anchor plate. Allow the shoe ends to come together and remove the spring.
8. Remove the shoe assembly, along with the upper return spring and the adjusting screw assembly.
9. Remove the upper return spring and the adjusting screw assembly from the shoes.
10. Remove the retaining ring, pin, spring washer, and parking brake lever.

Typical rear drum brake assembly (Leading/Trailing type)

To Install:

1. Clean adjuster wheel and the backing plates with a suitable cleaner. Lubricate the backing plate contact points, levers and adjuster with a suitable lubricant.
2. Assemble the parking lever, spring washer (concave side facing the brake lever), pin, and retaining ring onto the rearward shoe.
3. Install the adjuster pin in the forward shoe with the pin projecting 0.276 in. (7mm) from the side of the shoe web where the adjuster actuator is installed.
4. With the brake shoes resting on a flat surface (the shoe with the parking lever to the rear of the vehicle), install the upper return spring.
5. Install the adjuster screw assembly with the spring clip facing the backing plate.
6. Place the shoes in position on the backing plate. Do not place the lower shoe webs under the anchor plate.
7. Install the lower return spring, spread the bottom of the shoes and position the shoe against the backing plate.
8. Install the hold-down pins and spring assemblies.
9. Install the adjuster actuator over the end of the adjuster pin so the top leg engages the notch in the adjuster screw.
10. Install the actuator spring, being careful not to over-stretch it more than 3.27 in. (83mm).
11. Install the parking brake cable to the lever.
12. Adjust the parking brake if the shoes will not totally retract.
13. Install the drum, tire and wheel assembly. Adjust the rear brakes and lower the vehicle.

Brake Shoes Removal & Installation To Remove:

1. Raise and safely support rear of vehicle.
2. Remove rear wheel assemblies.
3. Release parking brake.
4. Remove brake drum.

Rear brake shoe assembly

1. Using an appropriate brake spring tool, unhook upper return spring from rearward brake shoe.
2. Push retainer springs IN and turn to remove tension pins.
3. Lower brake shoe assembly and remove lower return spring.
4. Remove brake shoe assembly from back plate.
5. Disconnect parking brake cable from lever and remove brake shoe.
6. Remove parking brake lever from brake shoe.

To Install:

1. Install parking brake lever to rearward brake shoe.
2. Secure lever to brake show with a NEW U-clip.
3. Pinch U-clip closed.
4. Connect parking brake cable to rearward brake shoe.
5. Install self-adjuster lever spring on front brake shoe.
6. Assemble clevises, adjuster bolt and upper and lower return springs.
7. Apply a light coat of grease (Molykote 44MA or equivalent) to sliding surfaces.
8. Install brake shoe assembly onto back plate.
9. Install tension springs.
10. Using an appropriate brake spring tool, unhook upper return spring to rearward brake shoe.
11. Install brake drum.
12. Install rear wheel assembly.
13. Lower vehicle.
14. Adjust self-adjusting brakes by pressing brake pedal several times.

You need to back off the adjusters on the rear shoes to allow the worn drum to pass over the brake shoes.
A worn drum will have a unworn drum section on its outer edge where the brake shoes don't normally rub.
This must unworn ring must be able to pass over the brake shoes before you can get the drum off.

Two tools should be used through the brake adjuster access hole.
One small diameter blade screwdriver can be used to push the self adjuster lever away from the notched adjuster nut, while a second flat bladed tool is used to lever the adjuster nut, rotating it so as to back off brake shoe expander adjustment.

Raise the Tahoe's rear end on jack stands. Block the front wheels and remove both of the rear wheels. Release the parking brake. Remove the brake drum, cutting off the pressed metal washers with a strong cutting tool.
If the drum won't come off because the drum shoes have worn into the drum, retract the shoes by removing the access plug from the backing plate. Push the lever off the adjuster star wheel with a small screwdriver and turn the star wheel with another screwdriver.
Clean off the entire assembly with break cleaner, using a drain pan to catch the residue. Never blow away brake dust with compressed air. Detach the spring from the adjuster level from within the drum by gripping it Detach the spring from the adjuster level from within the drum by gripping it shoe. Remove the trailing shoe and adjuster lever. Remove the adjuster screw assembly. Pull away the retractor spring and remove the leading shoe. Disconnect the trailing shoe from the parking brake lever.

Clean off the backing plate and lightly lubricate its shoe contact areas with high-temperature grease. Clean the adjuster screw assembly and lubricate the threads and socket end. Inspect the condition of the drum itself. If there are any cracks, score marks, deep scratches or discolored areas that can't be removed with an Emory cloth, have the drum resurfaced at an automotive machine shop.

Attach the new trailing shoe to the parking brake lever, position it on the backing plate and install the retractor spring's end into its hole. Re-install the adjuster screw assembly, making sure it engages with the leading shoe. Lubricate and install the adjuster level on the trailing shoe.
Place the trailing shoe on the backing plate, making sure it properly engages with the adjuster screw assembly, and insert the retractor spring into its hole within the trailing shoe. Place the actuator spring within its hole in the leading shoe, stretch the spring and connect it to the adjuster level.
Install the drum back on the Tahoe. Turn the adjuster screw's star wheel until the drum slips over the shoes without rubbing them. Reconnect the wheels once the brakes are changed on both sides and lower the vehicle.

Good luck and go for a test drive. If you could find a empty parking lot, go in reveres and do a full brake application a 7 to 10 times. This will self adjust the brakes to ensure that both side's are adjusted the same.