Reconditioning Front Brake Calipers

Reconditioning front brake calipers

Special tools:
981 4071 STRAIGHTENING TOOL 981 4071 Straightening Tool

Collect the brake fluid
See Replacing the front brake calipers, B5244T5, B5254T2 Replacing the Front Brake Calipers.

Remove the securing spring and locating pins
See Replacing the front brake calipers, B5244T5, B5254T2 Replacing the Front Brake Calipers.

Remove the brake caliper and brake pads
See Replacing the front brake calipers, B5244T5, B5254T2 Replacing the Front Brake Calipers.

Remove the piston from the brake caliper





Note! Do not trap your fingers when the piston is pressed out.

Remove the dust cap before the piston is pressed out.
Place a block of wood in front of the piston. Carefully press out the piston using compressed air.

Cleaning and inspection




Clean the components in denatured alcohol.
Check the components for wear, damage, cracks and rust. Replace components if necessary.
Remove the sealing ring. Use weatherstrip tool 981 4071 STRAIGHTENING TOOL 981 4071 Straightening Tool or similar so as not to damage the edges of the groove.
Remove the rubber sleeves.
Check the rubber sleeves of the locating pins. Replace if necessary.
Always replace the sealing ring and dust boot when installing. Take particular care to clean the ducts and grooves for the O-ring and dust boot.
If the cylinder is badly marked, scratched etc., replace the complete caliper.
Remove minor rust deposits using fine sandpaper.
Check the bleed nipples, replace as necessary.

Install the piston in the brake caliper




Blow the ducts clean using compressed air.
Apply a thin layer of new brake fluid to the cylinders, the piston and the new sealing ring.

Install:
- the piston in the caliper. Carefully press the piston to the bottom
- the dust boot in the groove on the piston. Check that everything is positioned correctly
- the rubber sleeves in the caliper for the locating pins.

Install the brake caliper




Lubricate the locating pins (2) using grease. P/N 1161325-4.
Insert the locating pins into the rubber sleeves. The pins should slide into the sleeves easily.
Secure the brake hose (4) loosely in the caliper.

Install:
- a brake pad in the piston
- the other pad in the caliper holder
- the brake caliper. Tighten the locating pins to 30 Nm
- the securing springs (3)
- the protective caps (1).
Tighten the brake hose. Tighten to 16 Nm.

Fill and bleed the brake system
See Brake system, bleeding (using bleeding unit) Brake System, Bleeding (Using Bleeding Unit).

Pressure test the brake system




After the brake system has been bled it must be pressure tested.
Depress the brake pedal as if braking suddenly (so that the wheels would almost lock) for 30 seconds. Check that no leakage occurs from the brake nipples, hoses and joints.
Remedy any leakage.

Install the wheel
Installing wheels Service and Repair