Wondering if its that I need brakes pads already

Good morning,

I attached the procedure for replacing the pads below.

The rotors will release once you remove the caliper. Using a small hammer to release it from the rust is all you need.

https://www.2carpros.com/articles/how-to-replace-rear-brake-pads-and-rotors

Roy

REAR DISC BRAKE

BRAKE PAD : Removal and Installation

WARNING:
Clean dust on brake calipers and brake pads with a vacuum dust collector to minimize the hazard of airborne particles or other materials.

CAUTION:
- While removing brake caliper, do not depress brake pedal because piston will pop out.
- Do not damage piston boot.
- If any shim is subject to serious corrosion, replace it with a new one.
- Always replace shim and shim covers as a set when replacing brake pads.
- Keep disc brake rotors and brake pads free from brake fluid and grease.
- Burnish the brake pads and disc brake rotors mutually contacting surfaces after refinishing or replacing disc brake rotors, after replacing brake pads, or if a soft pedal occurs at very low mileage.
Refer to "Brake Burnishing" See: Disc Brake System > Procedures > Brake Burnishing.

REMOVAL

1.Remove rear wheel and tires using power tool. Refer to "Adjustment" See: Wheels and Tires > Procedures > Adjustment.

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2.Remove sliding pin bolts and position the brake caliper aside with wire.

CAUTION:
Do not twist or stretch the brake hose.

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3.Remove brake pads, brake pad retainers, shims and shim covers.

CAUTION:
When removing the brake pad retainers from the torque member, lift it in the direction indicated by the arrow as shown so that it does not deform.

INSTALLATION

1.Apply Molykote AS-880N grease or equivalent to the brake caliper fingers, between the shims and brake pads. Install inner shim to inner brake pad, and outer shim to outer brake pad.
2.Apply Molykote AS-880N grease to the brake pad retainer as shown.

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3.Attach brake pad retainers to torque member, then install brake pads, shims and shim cover assemblies.

CAUTION:
When attaching brake pad retainers, attach it firmly so that it is flush with torque member as shown.
4.Using a suitable tool, press in piston until brake pads can be installed, and then install brake caliper to torque member.

CAUTION:
When replacing brake pads with new ones, check brake fluid level in the reservoir tank because brake fluid returns to master cylinder reservoir tank when pressing piston in.
NOTE:
Use a disc brake piston tool (commercial service tool) to easily press piston.

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5.Install sliding pin bolts and tighten to the specified torque. Refer to x"BRAKE CALIPER ASSEMBLY : Exploded View" See: Brake Caliper > Removal and Replacement > Exploded View.
6.Burnish contact surface between brake pads and the disc brake rotor. Refer to "Brake Burnishing" See: Disc Brake System > Procedures > Brake Burnishing.
7.Check rear disc brake for drag.
8.Install rear wheel and tires. Refer to "Adjustment" See: Wheels and Tires > Procedures > Adjustment.