| To dismantle and reassemble (Fig. 6)
1. Ease the dust cover from the push rod end of the master cylinder body.
2. Withdraw the push rod assembly from the master cylinder body by releasing the circle from the groove in the open end of the cylinder bore.
3. Eject the piston and centre valve assembly from the cylinder bore by applying low pressure air to the feed port in the end of the body.
4. Detach the centre valve assembly from the shouldered end of the piston by easing the leaf of the thimble upward clear of the piston shoulder.
5. Remove the thimble and piston return spring from the stem of the centre valve by compressing the return spring and passing the small end of the valve stem through the key-shaped aperture in the thimble.
6. Withdraw the valve spacer and spring washer from the valve stem and ease the seal from the opposite side of the stem.
7. Ease the tapered seal from the shouldered end of the piston.
8. Reassembly is the reverse of the dismantling sequence but particular attention must be given to the following:
(i) All parts must be meticulously cleaned and reassembled under equally clean conditions.
(ii) The seal is fitted to the centre valve, flat face first, with a liberal coating of brake fluid.
(iii) The spring washer is fitted to the valve stem, domed face first, followed by the valve spacer so the "legs" encase the seal.
(iv) The piston return spring is fed onto the outside of the thimble and fitted to the valve stem, return spring first; the spring is compressed so the end of the valve stem can be locked in the key-shaped aperture in the thimble, ensure that the piston return spring is located centrally on the valve spacer.
(v) The tapered seal is fitted to the piston, flat face first and from the shouldered end of the piston with a liberal coating of brake fluid.
(vi) The piston is fitted to the thimble, press the leaf downward so that the valve and piston assembly lock positively together.
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(vii) Smear the piston with Girling Red Rubber Grease and feed the centre valve and piston assembly Into the cylinder bore, centre valve first, exercising care not to damage the fine lip of the seal and so the thimble leaf will be uppermost when the master cylinder is in its, fitted position, thus the air between the piston and thimble will rise when the hydraulic system is bled of air.
(viii) Smear the inside of the dust cover with Girling Red Rubber Grease and ensure that the circle, which secures the push rod assembly, is fully engaged in its groove in the open end of the cylinder bore.
GIRLING SERVICE KITS
Girling Service Kits, containing the necessary seal(s) and a tube of Girling Red Rubber Grease, are available. The appropriate Service Kit for the hydraulic component must always be obtained when any seal(s) need renewing. Full instructions are included with the seal(s) but the following instructions should be observed.
1. When the hydraulic component has been cleaned of outside dirt and dismantled, the cylinder bore and internal parts must be cleaned with Girling Cleansing Fluid and allowed to dry off.
2. Examine the cylinder bore and piston; when the working surfaces are smooth to the touch without corrosion, score marks or ridges, the new seal(s) can be fitted and the component re-assembled. When there is any doubt as to the condition of the working surfaces, a new replacement hydraulic component must be obtained.
3. All parts must be meticulously cleaned and reassembled under equally clean conditions.
4. Fit the new seal(s) to the cylinder bore, piston or valve with a liberal coating of brake fluid giving par-ticular attention to the position of the seal lip which is towards the pressure or feed supply of the fluid.
5. Smear the piston(s) with Girling Red Rubber Grease and insert into the cylinder bore, exercising care not to damage or fold back the fine edge of the seal(s).
6. Smear the inside of the dust cover(s) with Girling Red Rubber Grease, fit to the cylinder body and secure with the metal clip as necessary.
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