Cleaning and Inspection.

d. Cleaning and Inspection.

(7) Clean cylinder body using clean, soapy

water.

Caution: Do not use mineral base cleaning

(8) Rinse cylinder body using clean, warm

solvents such as gasoline, kerosene, carbon

water.

tetrachloride, acetone, paint thinners, etc., to clean

Warning: Wear suitable eye protection when

rubber parts.

using compressed air.

(1) Clean all master brake cylinder internal

(9) Dry cylinder body using compressed air.

parts using a lint-free cloth dampened in clean denatured

(10) Insure that intake port and bypass port

alcohol or hydraulic brake fluid.

passages are free of burrs, dirt, and other foreign matter.

(2) Remove dirt, metal filings, sludge, and

(11) Submerge cylinder body in clean hydraulic

other foreign matter from cylinder and tank and external

brake fluid.

cylinder parts.

f. Reassembly. (fig. 3-45.)

(3) Inspect cylinder bore for deep blemishes.

Note. If cylinder bore has been honed, insure

(4) If deep blemishes are found, cylinder shall

that new parts contained in repair kit are installed.

be honed and all new parts contained in repair kit will be

(1) Insure that all master brake cylinder

installed (sub-para e).

internal parts and cylinder bore have been coated with

(5) Inspect cylinder for pressure marks and

clean hydraulic brake fluid.

discoloration.

Caution: Do not use emery cloth or

Caution: Do not distort or crack cylinder

sandpaper to polish affected area.

body when securing cylinder in vise.

(6) If pressure marks and discoloration is

(2) Secure hydraulic master brake cylinder in

found, polish affected area using crocus cloth.

vise.

(7) Insure that intake port and bypass port

(3) Insure that large end of spring is

passages are free of burrs, dirt, and other foreign matter.

positioned as shown in figure 3-45 before installing valve

(8) Using a piece of soft, iron wire, probe

assembly (8) and spring assembly (7).

bypass port passage to insure that passage is open.

(4) Install valve assembly and spring

(9) Inspect all parts for corrosion.

assembly in bore of cylinder body.

(10) Inspect piston bearing surfaces for

(5) Place primary cup (6) in cylinder bore and

scratches or pitting.

install piston assembly 15).

(11) Inspect rubber parts for deterioration,

(6) While compressing spring and piston

swelling, softening, tackiness, and lack of spring-

assembly, install piston plate 14) and lockwire (3).

action.

(7) Insure that lockwire is seated in groove in

(12) Replace all parts which appear to be worn

end of cylinder.

or damaged.

(8) Install gaskets (9 and 10), outlet fitting

e. Repair.

(11), fluid passage bolt, and stop light switch in outlet

(1) Insure that master brake cylinder has

end of cylinder.

been cleaned in accordance with subparagraph d.

(9) Position boot (2) on push rod end of

(2) Apply a coating of clean hydraulic brake

cylinder.

fluid to walls of cylinder bore.

(10) Insert piston rod (11 through opening in

boot and insure that end of piston rod is seated in

Caution: Do not distort or crack

piston assembly.

cylinder body when securing cylinder in vise.

(11) Install nonmetallic washer (13) and filler

(3) Secure hydraulic master brake cylinder in

cap (12) but do not tighten.

vise.

(12) Remove cylinder from vise.

Note. Before honing cylinder bore, become

3-33. Seat Brake (fig. 3-46.)

familiar with honing equipment manufacture's

a. General.

operating and servicing instructions.

(1) The seat brake is an enclosed, two-shoe,

(4) Using

honing

equipment,

remove

mechanically operated brake, mounted on the drive

scratching, pitting, etc., from cylinder bore in single

motor armature shaft. The seat brake is actuated

passes.

through spring pressure and mechanical linkage which is

(5) After each pass is completed, visually

attached to the seat brake actuating cam. When spring

check cylinder bore for the absence of scratching,

pressure is applied to the actuating cam. pressure is

pitting, etc.

applied to the actuating arms, which move the brake

(6) If scratching, pitting, etc., is deep or

shoe linings in contact with the brake drum. As the spring

excessive and master brake cylinder bore would have to

pressure is removed front the actuating cam, the brake

be honed oversize (greater than 1.0070 inches), replace

shoes are returned to the neutral position by the brake

cylinder.

shoe return springs.

3-66