The caliper assemblies are identical in design and construction whether fitted to the front or to the rear brake. In both cases,
it will be necessary to remove the caliper from the fork lower leg or from the final drive housing as appropriate.
Each caliper is retained by two bolts.
The caliper units should be removed for overhaul if there has been any evidence of weeping from the seals. Note that seals
can sometimes leak enough to admit air to the system without allowing the fluid to leak out. Whatever the case, immediate investigation is warranted.
Start by disconnecting the brake pipe at the caliper gland nut and block the open pipe end with a suitable wooden or rubber plug. This will prevent
the ingress of contaminants and the loss of hydraulic fluid.
Remove the two socket screws which retain the caliper halves, to give access to each piston assembly. Remove the dust seal
and withdraw the piston and seals from each side. If the pistons are difficult to extract, wrap the caliper in thick rag and apply compressed air
to the fluid passage to force the pistons out. Examine all the components carefully. The seals should be renewed as a matter of course. The working
surface of the piston should be highly polished with no scores or corroded areas. If these are evident, the piston must be renewed or it will rapidly
destroy the new seals. The caliper bores are least likely to exhibit signs of wear or corrosion damage but if such evidence is present, it will
necessitate renewal of the caliper body as a unit.
The component parts should be cleaned thoroughly with new brake fluid prior to reassembly. On no account use petrol (gasoline)
or paraffin (kerosene) as these will ruin the seals. Reassemble, by reversing the dismantling sequence, ensuring that all parts are kept
clinically clean. Lubricate the seal and piston with hydraulic fluid prior to fitting them to the caliper. Make sure that the brake pipe is fitted
correctly. Before using the machine, bleed the brake system. See Section 9 - Bleeding the hydraulic brake system.