Ajust back brake calipers

Question edited for clarity.
Question moved to model category.

The parking brake is cable operated and normally only need adjustment.

https://www.google.com/search?q=2008+dodge+grand+caravan+3.3+parking+brake+adjustment

Information on caliper seals.

https://www.google.com/search?q=2008+Dodge+Grand+Caravan+3.3.+replace+the+caliper+piston+seal

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If the calipers are working properly they are self adjust for the life of the pads. If the park brake is not functioning properly maintenance is required, usually strip and clean road debris.

you should'nt have any tension on the parking brake,unless it's on. check the parking brake to insure that it's in the off position. chock" the rear wheels,to make sure the car does'nt roll while you're jacking it up and "always use jackstands,do not trust your jack" does your brake caliper piston have a + on it?it will be on the brake caliper piston itself, if so,then you need to back the brake caliper piston back in by turning it counterclockwise,auto parts stores sell a special tool to back the brake calipers back into place, i've always used a straight screwdriver,to turn the piston counterclockwise some do turn clockwise though to retract the brake piston. a simple call to the auto parts store where you're purchasing the brakes will tell you which way the piston will need to be retracted.other wise,it's a simple brake replacement,just push the brake caliper cylinder with a "C" clamp to retract the brake caliper, also,if you are replacing brake rotors,purchase the brake kleen to spray on the new brake rotors when you replace those.they have a clear film on them,you'll need to remove that film to insure no future issues with the brake rotors.simply spray the front and back of the brake rotors with this spray to remove the protective "film"and as always,thank you,for choosing fixya.com!

It's a cable adjustment under the car, It looks like a turnbuckle that you spin to take slack out of cable. Another item to try since your car is 4 wheel disc, the rear calipers are threaded not smooth like front calipers and have to be "walked out" - a local guy said pull up and release park brake lever a few times to walk pistons out a little before doing the turnbuckle adjustment

Okay, this is the step that says how to REMOVE the cable:

1. Remove retaining clip from the parking brake rear cable at the disc brake caliper. Release the tension from the parking brake cable and disengage the cable end from the parking brake lever on the brake caliper.
   

And this is the step that says how to INSTALL the cable:

1. Connect the end of the parking brake cable to the parking brake lever on the disc brake caliper.
   

disc brake calipers to my knowledge have no adjustment. they have problems due to improper bleeding, pads wearing out, and stuck components which do not allow pinching and relaxing with pushing and releasing of the pedal. if you are talking about the parking brake, that is a horse of another color.

Bonneville, LeSabre, Park Avenue 2000-2005

Brake Caliper - Removal & Installation

CAUTION Dust and dirt accumulating on brake parts during normal use may contain asbestos fibers from production or aftermarket brake linings. Breathing excessive concentrations of asbestos fibers can cause serious bodily harm. Exercise care when servicing brake parts. Do not sand or grind brake lining unless equipment used is designed to contain the dust residue. Do not clean brake parts with compressed air or by dry brushing. Cleaning should be done by dampening the brake components with a fine mist of water, then wiping the brake components clean with a dampened cloth. Dispose of cloth and all residue containing asbestos fibers in an impermeable container with the appropriate label. Follow practices prescribed by the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA) for the handling, processing, and disposing of dust or debris that may contain asbestos fibers.
Inspect the fluid level in the brake master cylinder reservoir. If the brake fluid level is midway between the maximum-full point and the minimum allowable level, no brake fluid needs to be removed from the reservoir before proceeding. If the brake fluid level is higher than midway between the maximum-full point and the minimum allowable level, remove brake fluid to the midway point before proceeding.

1. Raise the vehicle and suitably support.
2. Remove the tire and wheel assembly.
3. Pull down on the front park brake cable.
4. Remove the front park brake cable from the park brake cable connector.
   NOTE When using a large C-clamp to compress a caliper piston into a caliper bore of a caliper equipped with an integral park brake mechanism, do not exceed more than 1 mm (0.039 in.) of piston travel. Exceeding this amount of piston travel will cause damage to the internal adjusting mechanism and/or the integral park brake mechanism.
5. Install a large C-clamp over the top of the brake caliper housing and against the back of the outboard brake pad. Compress the brake caliper piston into brake caliper bore to allow the piston enough clearance to slide the brake caliper off the brake rotor.
6. Remove the C-clamp.
   NOTE Be sure to plug the opening in the brake caliper and brake hose to prevent fluid loss and/or contamination.
7. Remove brake hose to caliper bolt attaching the brake hose to the brake caliper.
8. Remove the brake hose from the brake caliper.
9. Remove and discard the two copper brake hose gaskets. These gaskets may be stuck to the brake caliper and/or the brake hose end.
10. Remove the park brake cable bracket from the brake caliper. Leave the park brake cable attached to the cable bracket.
11. Disconnect the park brake cable from the park brake lever on the brake caliper.
12. Remove the lower brake caliper pin bolt.
13. Rotate the brake caliper up.
14. Remove the brake caliper from the upper brake caliper pin bolt.
    

To install:

1. If reusing the brake caliper retainers, clean the sleeves using denatured alcohol, or equivalent.
2. Lubricate the brake caliper pin bolts with a thin coat of high temperature silicone lube.
3. Install the brake caliper to the upper caliper pin bolt.
4. Rotate the brake caliper down over the brake pads into the brake caliper bracket.
5. Install the brake caliper pin bolts. Tighten the brake caliper pin bolts to 27 Nm (20 ft. lbs.).
6. Remove the plugs in the brake hose end.
   NOTE Install NEW copper brake hose gaskets.
7. Assemble the brake hose bolt and the NEW copper brake hose gaskets to the brake hose.
8. Install the brake hose to caliper bolt to the brake caliper. Tighten the brake hose to caliper bolt to 44 Nm (33 ft. lbs.).
9. Connect the park brake cable to the park brake lever on the brake caliper.
10. Install the park brake cable bracket to the brake caliper. Tighten the park brake cable bracket bolt to 43 Nm (32 ft. lbs.).
11. Install the front park brake cable to the park brake cable connector.
12. Bleed the brake system.
13. With the engine OFF, gradually apply the brake pedal to approximately 2 / 3 of its travel distance.
14. Slowly release the brake pedal.
15. Wait 15 seconds, then repeat until a firm brake pedal is obtained. This will properly seat the brake caliper pistons and brake pads.
16. Install the tire and wheel assembly.
17. Lower the vehicle.
    

NOTE The Bosch 2U ABS system cannot increase brake pressure above master cylinder pressure applied by during braking. There is no need to depressurize the system prior to service.

1. Remove brake fluid from the master cylinder reservoir until the reservoir is approximately 1 / 3 full.
2. Remove the front wheel. Mark the position of the wheel to the wheel studs, prior to removal, for installation reference.
3. Install 2 lug nuts to retain the rotor once the caliper is removed.
4. Using a large C-clamp, bottom the piston in the caliper bore by positioning the C-clamp on the outboard pad and on the round portion of the brake caliper where the piston is housed.
5. Remove the banjo bolt that fastens the brake hose to the brake caliper. Discard the gaskets.
6. Cap the brake line to avoid excessive fluid loss or fluid contamination.
7. Remove the rubber dust boots from the caliper mounting bolt heads (if equipped).
8. Remove the caliper mounting bolts.
9. Remove the park brake cable from the caliper.
10. Remove the caliper from the vehicle.
11. Remove the brake pads.
    

To install:

1. Install the brake pads. Lubricate the slides where the caliper mounts on the steering knuckle with silicone grease.
2. Install the caliper over the rotor.
3. Install the caliper mounting bolts. Torque the mounting bolts to 38 ft. lbs. (51 Nm).
4. Install the park brake cable.
5. Install the rubber dust boots over the caliper mounting bolt heads (if equipped).
   
   
   Fig. Measuring the caliper clearance
   
6. Check the clearance between the brake caliper and caliper bracket stops. If the clearance is too tight, check the caliper leading and trailing edges for build up. File down as necessary.
7. Connect the brake hose to the caliper. Install the brake hose banjo bolt, using new gaskets, and torque to 33 ft. lbs. (45 Nm).
8. Remove the lug nuts used to secure the rotor.
9. Install the wheel, aligning the reference marks made during removal, and torque the lug nuts to 100 ft. lbs. (140 Nm).
10. Refill the master cylinder and bleed the brake system using the recommended procedure.
11. Road test the vehicle and check for proper braking performance

Hope helps (remember rated this).

YOU NEED TO REMOVE THE REAR WHEELS.REMOVE PARKING BRAKE CABLE CLIP FROM CALIPER DISCONNECT PARKING BRAKE CABLE.HOLD THE GUIDE PIN WITH A BACK UP WRENCH AND REMOVE UPPER MOUNTING BOLT FROM THE BRAKE CALIPER.SWING THE CALIPER DOWNWARD AND REMOVE THE BRAKE PADS.TO INSTALL NEW PADS.YOU HAVE TO RETRACT PISTON INTO THE HOUSING BY ROTATING THE PISTON CLOCKWISE.PUT EVERYTHING BACK VISA VERSA.

YOUR MOST LIKELY PROBLEM IS IN THE REAR ROTORS. THE PARK BRAKE AREA WILL RUST INWARD WEARING OUT THE PARK BRAKE SHOE. THE ADJUSTER IS UNDER THE ROTOR ALSO. ONE ON EACH SIDE.

ADJUST THE SHOE OUT UNTIL IT TOUCHES THE DRUM AND THEN BACK IT OFF ABOUT 6-7 CLICKS.

it's only supposed to adjust to the point where it works...otherwise it would tighten up from use and stop you dead.