Minggu, 15 Mei 2011

How to Retract Calipers on a Toyota Sienna

How to Retract Calipers on a Toyota Sienna

You must retract the caliper pistons on your Toyota Sienna when you're replacing pads or rotors. Because Siennas can feature front and rear disc brakes, this applies to both axles. Retracting the pistons that contact the backing plate of the outboard pad makes room for the new, thicker pads or rotors. Trying to force a caliper onto new disc brakes could damage the piston, and in all likelihood you would still not be able to get it onto the new brakes.



things you'll need:

  • Wheel block
  • Brake fluid suction baster (or a turkey baster)
  • Wheel lug wrench
  • Car jack
  • Jack stand(s)
  • Metric box-end/open-end combination wrench set
  • Slotted screwdriver
  • Caliper hook or bungee cord
  • Caliper piston reset tool or a 6-inch C-clamp
  • Small pick set
  • Brake fluid
    • 1

      Apply the parking brake on a flat hard surface if you're working on the front axle of the Toyota Sienna. If you're working on the rear axle, place a wheel block in front of one of the front tires on the Sienna, and make sure the vehicle is in gear with the keys removed from the ignition.

    • 2

      Open the hood and remove about half of the fluid from the master cylinder brake fluid reservoir (on the driver's side firewall), using a brake fluid suction baster or a turkey baster. If using a turkey baster, never allow it back into the kitchen; brake fluid is highly toxic. Replace the cover of the master cylinder.

    • 3

      Loosen the wheel lugs of the wheel(s) on which you're intending to replace the brakes or remove the calipers, using the wheel lug wrench. Turn the nuts 1/8 of a turn, lift the axle off the Sienna using the car jack and then support the car safely onto jack stands. Finish removing the wheel lugs, then remove the wheels and set them aside.

    • 4

      Use a metric open-end wrench to hold the two caliper sliding pins in place while removing the two caliper mounting bolts with a box-end wrench. Turn the bolts counterclockwise to unscrew them.

    • 5

      Gently pry the caliper off the pads and caliper mount assembly that are embracing the rotor. Support the caliper to the suspension coil spring with a hook or bungee cord to ensure it does not dangle from the rubber hydraulic brake hose.

    • 6

      Compress the caliper piston, using the caliper reset tool or the 6-inch C-clamp. There are a few ways you can do this. You can use one of the old pads as a protective barrier between the desired retracting tool and the piston of the caliper to ensure you do not damage it. You can also place a small block of wood against the piston. Or you can place the driving bore of the C-clamp inside the hollow piston while the top of the clamp sits against the inside housing of the caliper. In any case, tighten the clamp slowly until the caliper piston is fully retracted into the bore.

    • 7

      Remove the retracting tool and inspect the protective caliper piston boot. Often times when compressing caliper pistons, the boot can get air trapped inside it, distorting its position. If necessary, use a small pick set to pull the boot away from the piston in the compromised location, and allow the trapped air to escape and reset the boot properly. Do not poke a hole in the rubber boot with the pick.

Tips & Warnings

  • With the caliper pistons retracted, you can continue on with your intended repair.

  • On rear disc brake calipers on the Sienna, removing the parking brake cable from the caliper is also required to properly extract it from the caliper mount.

  • When the Sienna repairs are complete and the vehicle is back on the ground, pump the brake pedal several times to push the pistons back out of the caliper bores and seat them against the pads and rotors. Do this before test-driving the Sienna or you will not have an initial braking response, which could cause a serious accident. Once the pedal feels firm, recheck the brake fluid in the master cylinder and top it off only with new brake fluid. Any other hydraulic fluid will contaminate the braking system and cause complete brake failure. Use DOT 3 brake fluid.

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