Master Cylinder Disassembly/Assembly

Figure 1 Exploded View Of Composite Master Cylinder:

Disassembly
1. Remove reservoir cap (8) and diaphragm (7). Inspect cap for cracks or other damage and replace if necessary.
2. Discard any fluid from reservoir or bore.

Figure 2 Depressing Pistons To Remove Stop Bolt:

CAUTION: Do not remove stop bolt unless both pistons are fully bottomed in bore.

3. Fully depress the master cylinder pistons with a brass rod or wooden dowel (27) as shown in and remove stop bolt (3) Then remove snap ring (17) with retaining ring pliers.

Figure 3 Primary Piston Assembly:

4. Remove brass rod or wooden dowel (27) and primary piston (15).

Figure 4 Secondary Piston Assembly:

5. Gently bump open end of master cylinder body (1) on a piece of wood to dislodge the secondary piston (11) and center valve assembly (7).
6. Remove the seal retainer (12) by carefully prying open the legs of the seal retainer with a small screwdriver.

CAUTION: Do not remove or disturb the screw in the secondary piston assembly (11) This will alter piston performance and make replacement of the piston assembly necessary.

7. Remove the seals (13 and 16) and the recuperating guide (14).
8. Remove seals (10 and 16), working over secondary piston lands
9. Remove the warning switch assembly (18) being careful to keep the switch spring and probe together as an assembly.
10. Remove the end plug (22).
11. Remove the "O" ring (21) from the end plug (22).
12. Gently bump the master cylinder body (on a piece of wood to dislodge the combination piston (19) with spring (20) attached.

NOTE: Do not disassemble this piston as it is serviced as a complete assembly.

Assembly

CAUTION: Do not wash new combination piston (19) in any cleaning solution. The internal components are pre-lubricated with special grease.

1. Clean all parts, not included in repair kits, in clean denatured alcohol. Use dry, filtered compressed air to dry parts and blow out all passages in the master cylinder body.
2. Lubricate seals (10 and 16) with clean fresh Supreme 11 brake fluid and install on secondary piston (11). Make sure that seal lips face away from each other.
3. Lubricate seal (16) with clean brake fluid and install on primary piston (15), with seal lips facing as shown.
4. Lubricate seal (13) with clean brake fluid. Install recuperating guide (14) and seal (13) on primary piston (15) as shown in with seal lips facing as shown.
5. Press new retainer (12) onto primary piston (15). Make sure retainer tabs snap into piston groove.
6. Lubricate cylinder bore and piston assemblies with clean brake fluid.
7. Insert new center valve assembly (9) into secondary piston (10, 11 and 16) assembly. Lubricate secondary piston then install in lubricated cylinder (1) bore.

CAUTION: Do not remove or disturb the screw in the center valve assembly (9). This will alter valve performance and make replacement of the valve assembly necessary.

8. Install primary piston with assembled parts (12 thru 16) in cylinder (1) bore.

CAUTION: Never install stop bolt (3) unless both pistons (11 and 15) are fully bottomed in bore.

9. Using brass rod or wooden dowel, push on the primary piston (15) until the primary and secondary pistons (15 and 11) bottom in the master cylinder bore.
10. Install the stop bolt (3) and torque to 10 Nm (7 ft-lb).
11. Install a new snap ring (17) in the master cylinder bore making sure it fits into the groove properly. Remove brass rod or wooden dowel.
12. Lubricate the combination piston bore and a new combination piston (19) with clean brake fluid and insert the piston, open end first, into the bore. Make sure the piston is fully bottomed.
13. Fit spring (20) over piston end cap (19) (in cylinder).
14. Lubricate a new 0-ring (21) with clean brake fluid and install it over the threaded end of the end plug (22).
15. Install the end plug into cylinder body (22) and torque to 25 Nm (19 lb-ft).
16. Install warning switch assembly.
17. Install new diaphragm (7) on the reservoir cap (8).
18. Install master cylinder assembly.