Figure 5-15. Master cylinder.

(1) Secure master cylinder in a vise, using

require honing to resurface the cylinder wall. Pressure

care not to crack or distort cylinder housing.

marks may be polished out with crocus cloth.

(2) Remove boot (2, fig. 5-15) and piston rod

(1).

CAUTION

(3) Hold piston in cylinder and remove lock

Do not use emery cloth or sandpaper.

wire (3) by gentle prying.

(3) Make sure intake and bypass ports are

CAUTION

open. Bypass ports may e probed with soft iron wire.

When lock wire is removed, the entire

(4) If it is necessary to resurface the cylinder

wall, follow the honing equipment manufacturers

piston assembly will spring out if not

recommendations. Do not hone cylinder oversize.

held in place.

(5) Before assembly, inspect parts for

(4) Carefully remove copper stop plate (4),

corrosion, scratched or pitted piston bearing surfaces,

piston (5), piston cup (6), spring (7), and valve (8).

rubber deterioration, and defective spring action.

(5) Working from the other end of cylinder,

Replace worn, damaged, corroded, or deteriorated parts

remove outlet fitting bolt (15), gasket (14), outlet fitting

as authorized.

(13), and gasket (12).

e. Assembly and Installation. Reverse procedures

(6) Remove filler cap (11) and gasket (10).

in b and c above. Refer to TM 10-3930-618-20 for

d. Cleaning and Inspection.

hydraulic brake bleeding.

(1) Clean all parts with denatured alcohol or

brake fluid, and keep clean in all following operations.

1 Piston rod

12 Gasket

2 Boot

13 Outlet fitting

3 Lock wire

14 Gasket

4 Stop plate

15 Fitting bolt

5 Piston assembly

16 Lockwasher

6 Piston cup

17 Capscrew

7 Spring and retainer

18 Jamnut

8 Check valve

19 Yoke

9 Cylinder and tank

20 Yoke pin

10 Gasket

21 Cotter pin

11 Filler plug

Figure 5-15. Master cylinder.

5-20