Front Brake Caliper Reconditioning

Front brake caliper reconditioning

Special tools:
981 4071 STRAIGHTENING TOOL 981 4071 Straightening Tool

Preparations
Remove the hub cap and the wheel.
Clean brake caliper carefully.

Draining off brake fluid




Remove the protective cap from the bleed nipple, connect a hose and open the nipple.
Lock pedal in depressed position using a pedal jack.
Use a container to collect brake fluid.
Loosen the bolt of the brake hose mounting.

Front brake caliper complete removal





Remove
- the banjo bolt with the sealings.
- the two bolts from the brake caliper guide pin.
- the brake caliper from the holder.
- the brake pads.
- the remaining brake fluid.

Remove piston from brake caliper





Warning! Take care not to get your fingers caught when pushing out the piston.

Put a block of wood in front of the piston. Push the piston out carefully using compressed air.

Dismantling front brake caliper





Remove
- the dirt guard.
- use straightening tool 981 4071 STRAIGHTENING TOOL 981 4071 Straightening Tool or something similar, to avoid damaging the edges of the grooves.
- the bleed nipple.

Cleaning and inspecting the brake caliper
Clean components with denatured alcohol.
Check for wear, damage, cracks and rust. Replace components if necessary.
Always replace the "O" ring and the dirt guard during overhaul. Pay particular attention to ensuring that the ducts and the grooves for the "O" ring and the dirt guard are clean.
If the cylinders are badly marked or scratched, the caliper should be completely replaced.
Remove minor rust deposits with fine sandpaper.

Assembling front brake caliper




Clean the components with compressed air.
Lubricate the cylinder wall, the piston and the new "O" ring with brake fluid.

Install
- the "O" ring in the cylinder.
- the dirt guard on the piston.
- the dirt guard (with piston) in the groove of the cylinder.
Press the piston in carefully.
Ensure that the dirt guard is correctly positioned.
Install the bleed nipple and tighten to 5 Nm.

Finishing





Inspect
- the brake disc, see operation Replacing front brake pads Replacing Front Brake Pads.
- the brake caliper guide, see operation Replacing front brake pads Replacing Front Brake Pads.
Install the brake pads, paying attention to the wear-indicator.
Install the brake caliper to the guide pins.
Tighten to 35 Nm.
Install the brake hose. Use new sealings.
Tightening torque 15 Nm.
Make sure that the brake hose is not twisted.
Bleed the brake system, see operation Bleeding brake system Service and Repair.
Install the wheel, see operation Replacing front brake pads Replacing Front Brake Pads.