Cant find what size or what they used ?? who has did brakes of

The hex size to remove the brake caliper on a 2000 Jeep Cherokee is typically 17mm or 11/16 inches.
It's important to use the correct size socket or wrench to remove the brake caliper, as using the wrong size can cause damage to the caliper and/or the brake system.
When removing the brake caliper, it's important to take the proper precautions to prevent damage to the brake system and ensure safe operation of the vehicle. Always support the caliper with a wire or a bungee cord to prevent it from hanging by the brake hose.
Additionally, it's recommended that you work on one brake at a time, so that you have a reference point for the position of the caliper and the brake pads.

if you dont know what to do you have no right working on brakes.

Start at the caliper furthest from the master cyclender, should be right rear then move to left rear followed by right front and lastly left front! I have done many different cars over the years and this procedure allway works perfectly:)

Allen wrench size to remove brake caliper on my 2008 mercury mariner

For front brake pads replacement you only need usually wrench set, inclusive 7 mm allen key also. But for rear brake pads replacement you need obligatory a special caliper piston pressing tool, in order to press back rear caliper piston with parking brake automatic adjustment!!!
Instructions for front brake pads replacement.
For change front brake pads you must raise vehicle, remove wheels, extract the retaining spring of the caliper, and remove the caliper as follow:
1. Do not disconnect the brake hose from the caliper, and do not allow the caliper to hang by the brake hose!
2. Remove top and bottom caps (on back side of the caliper) for access to guide pins, then unbolt and remove them from the brake carrier. Remove the caliper.
3. Now you must thoroughly clean the brake calipers (free of grease).
4. Remove outer brake pad from brake carrier.
5. Pull inner brake pad out of brake caliper piston.
6. Check up the brake fluid level on the reservor, and emptying if neccessary!
7. Push piston back into brake caliper housing.
8. Install inner brake pad (with expanding spring) in brake caliper piston. (Arrow marked on pad - if exist, must point in direction of brake disc rotation when vehicle is moving forward).
9. Install outer brake pad into brake carrier.
10. Bolt brake caliper housing to brake carrier using two guide pins. Tightening torque is 25 Nm.
11. Install both caps.
12. Insert retaining spring into brake caliper housing.
Important note: Depress the brake pedal firmly several times while the car is stationary so that the brake pads adjust to their normal operating positions!!!
Check brake fluid level and top up as neccessary!

For front brake pads replacement you need only usually wrench set, inclusive 7 mm allen key also. But for rear brake pads replacement you need obligatory a special caliper piston pressing tool, in order to press back rear caliper piston with parking brake automatic adjustment!!!
For front brake pads. First you must verify yours front brake disc diameter: 280 mm or 288 mm. After that you can buy the brake pads (with wear sensor). For change front brake pads you must raise vehicle, remove wheels, extract the retaining spring of the caliper, and remove the caliper as follow:
1. Do not disconnect the brake hose from the caliper, and do not allow the caliper to hang by the brake hose!
2. Remove top and bottom caps (on back side of the caliper) for access to guide pins, then unbolt and remove them from the brake carrier. Remove the caliper.
3. Now you must thoroughly clean the brake calipers (free of grease).
4. Remove outer brake pad from brake carrier.
5. Pull inner brake pad out of brake caliper piston.
6. Check up the brake fluid level on the reservor, and emptying if neccessary!
7. Push piston back into brake caliper housing.
8. Install inner brake pad (with expanding spring) in brake caliper piston. (Arrow marked on pad - if exist, must point in direction of brake disc rotation when vehicle is moving forward).
9. Install outer brake pad into brake carrier.
10. Bolt brake caliper housing to brake carrier using two guide pins. Tightening torque is 25 Nm.
11. Install both caps.
12. Insert retaining spring into brake caliper housing. Important: Depress the brake pedal firmly several times while the car is stationary so that the brake pads adjust to their normal operating positions!!! Check brake fluid level and top up if neccessary!!!

For front brake pads replacement you need only usually wrench set, inclusive 7 mm allen key also. But for rear brake pads replacement you need obligatory a special caliper piston pressing tool, in order to press back rear caliper piston with parking brake automatic adjustment!!! For front brake pads. First you must verify yours front brake disc diameter: 280 mm or 288 mm. (On my car y have 288 mm). After that you can buy the brake pads (with wear sensor). For change front brake pads you must raise vehicle, remove wheels, extract the retaining spring of the caliper, and remove the caliper as follow:
1. Do not disconnect the brake hose from the caliper, and do not allow the caliper to hang by the brake hose!
2. Remove top and bottom caps (on back side of the caliper) for access to guide pins, then unbolt and remove them from the brake carrier. Remove the caliper.
3. Now you must thoroughly clean the brake calipers (free of grease).
4. Remove outer brake pad from brake carrier.
5. Pull inner brake pad out of brake caliper piston.
6. Check up the brake fluid level on the reservor, and emptying if neccessary!
7. Push piston back into brake caliper housing.
8. Install inner brake pad (with expanding spring) in brake caliper piston. (Arrow marked on pad - if exist, must point in direction of brake disc rotation when vehicle is moving forward).
9. Install outer brake pad into brake carrier.
10. Bolt brake caliper housing to brake carrier using two guide pins. Tightening torque is 25 Nm.
11. Install both caps.
12. Insert retaining spring into brake caliper housing. Important: Depress the brake pedal firmly several times while the car is stationary so that the brake pads adjust to their normal operating positions!!! Check brake fluid level and top up if neccessary!!!

You Will Need A 13-14 mm Wrench for Caliper Bolts .A Large Flathead Screwdriver to Spred open Caliper/Shoes to Remove Caliper from Rotor,
After rhis you Can use a LARGE "C" Clamp to CLOSE Caliper Piston.

here is procedure

Section 04-01: Suspension and Wheel Hubs, Front 1996 Taurus, Sable Workshop Manual
REMOVAL AND INSTALLATION Wheel Hub Bolt Removal

1. Raise vehicle on hoist.
   

1. Remove wheel and tire assembly. Refer to Section 04-04 .
   

1. Remove disc brake caliper (2B120), and front disc brake rotor (1125). Refer to Section 06-03 .
   

Brake Shoe and Lining Removal

1. Remove brake master cylinder filler cap (2162). Check fluid level in brake master cylinder reservoir (2K478). Remove brake fluid until brake master cylinder reservoir is half full. Discard removed fluid.
   

1. Raise vehicle on hoist. Refer to Section 00-02 .
   

1. Remove wheel and tire assembly from front disc brake rotor mounting face. Use care to avoid damage or interference with disc brake caliper (2B120), front disc brake rotor shield (2K004) or front wheel knuckle (3K185).
   

1. Remove rear brake pin retainers (2N386). ( I think it is a T 40 torx bit you need)
   

1. NOTE: It is not necessary to disconnect hydraulic connections.
   
   Lift disc brake caliper from front disc brake caliper anchor plate (2B292) and front disc brake rotor (1125). Do not pry directly against metal caliper piston or damage will occur.
   

1. Position disc brake caliper out of the way and support with wire to avoid damaging the disc brake caliper and front brake hose (2078).
   

1. Remove outer brake shoe and lining (2001) assembly from front disc brake caliper anchor plate.
   

1. Remove inner brake shoe and lining assembly.
   

1. Position lug bolt (1107) to clear front wheel knuckle (3K185).
   

1. Remove lug bolt from wheel hub (1104).
   
   
   
   

Installation

1. Install lug bolt into wheel hub.
   

1. Using a lug nut (1012), seat wheel hub bolt into wheel hub.
   

1. Install front disc brake rotor and disc brake caliper. Refer to Section 06-03 .
   

1. Install wheel and tire assembly. Tighten lug nut to 115-142Nm (85-104 lb-ft).
   

It should be a 40 or 45 torx bit if the allens don't work.