Replacing The Master Cylinder; Removing A Brake Unit - MG MGA Twin Cam Workshop Manual

traces of petrol (gasoline), paraffin (kerosene), or trichlorethylene used for cleaning the metal parts
must be removed before assembly.
Examine all the rubber parts for damage or distortion. It is usually advisable to renew the rubbers
when rebuilding the cylinder. Dip all the internal parts in brake fluid and assemble them wet. Fit the
valve seal around the seal bush and the 'O' ring in the groove on the piston.
Place the seal bush in position on the valve stem and insert the piston into the spring support,
ensuring that the head of the valve engages the piston bore. Slide the complete assembly into the
cylinder body, taking particular care not to damage or twist the O-ring.
Position the push-rod and depress the piston sufficiently to allow the dished washer to seat on the
shoulder at the head of the cylinder. Fit the circlip and check that it fully engages in the groove.
Fill the dust excluder with Wakefield No. 3 Rubber Grease and reseat the excluder around the head of
the master cylinder.
M.6 REPLACING THE MASTER CYLINDER
The replacement procedure is the reverse of the removal instructions given in Section M.3.
After replacement, bleed the brake system as detailed in Section M.2. Finally, check for leaks with the
brakes fully applied.
M.7 REMOVING A BRAKE UNIT
Front
Unscrew the brake pipe union nut below its support bracket and disconnect and blank off the pipe.
Remove the two nuts securing the brake hose support bracket and remove the bracket.
Fig. M.3 A front disc brake calliper
Unscrew the two calliper retaining bolts and remove the calliper assembly complete with cylinders.
Take care not to misplace the shims which are fitted behind the mounting lugs on the calliper body.
The shims must be retained for reassembly and replaced in their original positions
Rear
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