The adjustment is carried out by means of the shoe adjusters located on the fork lever No. 00671909. Proceed as follows:
Ensure that the hand brake is free, turn on the adjusters until the brake shoes touch the brake drums, turn back three turns and lock with counternut.
It is important to follow the above procedure exactly, as, in this way, although one has a prompt and powerful locking action, as soon as the pedal is actuated a sufficient movement is guaranteed to the shoes, so that the maximum pressure of the cylinder takes place only after the main piston seal has passed the feed hole of the container in the cylinder body. This eliminates the rapid deterioration of the seal.

After the adjustment of the hydraulic system, check the hand control and, if necessary, act on the cable adjusters.

The efficiency of the hydraulic brake system depends on its being free from air bubbles. Therefore after any repair in which a tube has been detached, it is necessary to eliminate the air bubble which could have formed in the circuit. The presence of air in the hydraulic circuit can be ascertained by the abnormal softness of the brake pedal when pressed. To carry out the air bleed, proceed as follows:

Remove the protection cap of the air bleed screw on one of the rear wheel brake cylinders, (See Fig, 56) and fit to the screw a plastic tube ; then place other end of tube into a glass or tin containing brake fluid.

Unscrew air bleed screw and press brake pedal fully down, and release it slowly. Repeat the operation until no air bubbles are seen in the container.

Having thus eliminated the air bubbles, keep pedal pressed down, tighten air bleed screw, remove plastic tube and refit the protection cap.

After every air bleed operation, check level of brake fluid in the master cylinder reservoir (Fig. 57). The rear brake shoes are fitted with threaded pins to facilitate their positioning in respect or the back plates.

During normal usage, it is not necessary to carry out any adjustment, however it is opportune, when dismantling, to ascertain that the pins are well blocked. Fitting a serrated washer between nut and shoe will ensure the locking. This system has been applied on vehicles of the latest production.

To remove the rear brake master cylinder from frame. Take away panel (operation 121), remove the two petrol pipe clips, unscrew the union at the rear of the cylinder, 10 mm spanner, detach the electric wires from the stop switch, unscrew side nut and bolt (14 mm spanner) fixing the cylinder to the frame, detach the pedal return spring and withdraw cylinder with his rubber hose.

To remove rear brake pedal. Detach central pavement panel (Operation 121) remove the four screws, two on the right and two on the left, fixing the engine tray to the pavement, detach the tray, remove the split pin on the pedal link pin, remove the washer and pin, detach return spring, remove internal split pin on pedal shaft, slide out shaft by tapping it from the outside, move the pedal axially towards the inside to free it from the buffer. Remove the pedal rubber and remove pedal from underneath, rotating it to allow its passage through the hole in the footboard.

To remove the rear brake hand lever. Detach the floor central panel (operation 121) withdraw the split, pin on the lever pin, remove the shim, remove the lever return spring, loosen the two screws fixing the notched quadrant to the frame, withdraw lever, remove pin fixing cable guide, and pulley, detach cable guide from the pulley and remove the pulley from the cable; remove the cable guide caps from the frame and then the cable through the slits in the guides.

Removal of master cylinder. Detach cylinder from frame - Op. 117.

Drain oil from cylinder reservoir by removing drain plug.

Remove dust protection cap.

To remove cylinder:

1st series
Remove the circlip - 00670548 and the washer, ex­tract the piston, extract the spring, body group and inlet valve.
Note: The supply valve consists of two rubber cups, an oil seal, and a cone valve which is fitted in the cylindrical seat in the body.
The two cups are of different shape and must not be mixed up. The rear cup 00670307 must be fitted with the lip facing the inside of the cylinder.

2nd series
Remove the circlip, the piston, valve holder and extract the spring.
Note: The two rubber cups fitted on the piston and valve holder are similar and interchangeable.
The one fitted on the piston must stick out in respect of the piston plane.

Removal of the rear wheel cylinders. Lift the rear of the vehicle - Operation 76.

Remove wheels, hubs and brake shoes - See operations 80, 81, 82.

Detach the tubing from the wheel cylinders; with a 10 mm spanner unscrew the two hexagonal unions, one per wheel cylinder and detach the tubes.

Withdraw the cylinders from their seats on the wheel back plates by pushing them from the outside.

Withdraw the pistons from their respective cylinders. For the reassembly carry out the above operations in the reverse way.