Removal:-
1 Release the air pressure from the system.
2 Remove the airlines from the actuator and the hydraulic pipes from the master cylinder.
3 Remove the four bolts from the cylinder and actuator support and withdraw the assembly.
4 Remove the three nuts and lockwashers and separate the master cylinder and actuator from the support. Note the number of shims between the master cylinder and the support as they control the clearance between the actuator pushrod and the master cylinder primary piston.
Dismantling:-
1 Mark the position of the cylinders in relation to the body.
2 Remove the bolts and separate the cylinders from the body. Remove the gasket.
3 Withdraw the piston assembly from the rear cylinder and remove the lubricator felt.
4 Withdraw the filter from the front cylinder. Remove the friction disc and withdraw the indicator rod.
5 Secure the pushrod assembly in a soft-jawed vice and remove the pushrod locknut. The spring tension can be overcome by hand pressure.
6 Withdraw the pushrod from the piston and body and remove the pushrod thrust washer. Remove the piston lubricator felt.
7 Remove the circlip from the body and withdraw the washers and felt ring. The filter in the body should not be removed unnecessarily.
8 Do not remove the seals or sealing rings unless replacement is necessary.
Inspection:-
1 Wipe the rubber components with a clean, dry cloth and was all other parts. Clean the filters.
2 Examine the sliding surface of the pushrod for scores and the bush in the body for wear. The rod should be a close sliding fit in the bush.
3 Examine the pistons for damage and the sliding surfaces for scores and wear.
4 Check the cylinders for dents or signs of scoring and corrosion. Slight corrosion may be removed with fine emery cloth.
5 Examine all rubber parts for wear, damage and deterioration.
Reassembly:-
1 Smear the seals, sealing rings, pushrod, bush and the sliding surfaces with the approved grease. Soak the felt ring and piston lubricator felts in the approved lubricant.
2 Press the seal into the body with the plain side to the bush. See fig N39. Insert the felt ring, with a washer on each side, into the body and secure with the circlip.
3 Assemble the seals to the pistons with the plain side towards the lubricator felt groove. Locate the sealing ring in the piston bore.
4 Place the thrust washer on the pushrod and position the piston with the boss in contact with the thrust washer. Care should be taken to avoid damaging the sealing ring.
5 Place the body on the pushrod with the air inlet port adjacent to the piston. Care should be taken to avoid damaging the body seal.
6 Position the pushrod return spring on the body and locate the retainer on the spring. Compress the spring using hand pressure and fully tighten the pushrod locknut.
7 Assemble the sealing ring in the groove in the body and the lubricator felts in the piston grooves, ensuring that the ends of the felt do not overlap.
8 Insert the rear piston assembly into the cylinder with the single mounting stud. Care should be taken to avoid damaging the piston seal.
9 Position the cylinder, together with a new gasket on the body and align the marks made when dismantling.
10 Install the indicator rod in the front cylinder and retain with the friction disc.
11 Position the cylinder on the body and align the marks made when dismantling. Insert the bolts and tighten the nuts to the specified torque. (18 lb.ft)
12 Install the filter in the cylinder.
13 Place the blanking disc in the recess in the front cylinder and position the support on the actuator. Install the master cylinder as described under 'Master Cylinder'.
Installation:-
1 Bleed the hydraulic brake system.
Check the airline connections for leakage.
Illustration of the air dual actuator:-
http://i24.photobucket.com/albums/c1...n/IMGP8509.jpg