Cleaning - TM-9-6685-202-140066

TM 9-6685-202-14

and spring washer (13). Withdraw the crank wheel shaft

I. Constant Vacuum Regulator, 6605-3065604,

through the top of the housing.

Valve Replacement

(7) To remove the vacuum pump valve stem,

Disassemble only those parts of the constant vacuum

unscrew the integral packing nut and then unscrew the

regulator that are necessary to effect repair or

stem. The asbestos packing (2) may be removed with a

replacement of authorized parts.

probe.

(8) Unscrew bushing (22) on the control valve

(1) Do not remove the crank wheel assembly

assembly.

from the upper housing unless there are broken or

(9) Pry one leg of spider (25) out of the

damaged parts.

groove with a screw driver and remove the spider.

(2) Do not remove bellows unit (35) from

(10) Remove machine screws (23); this will

lower housing (48) unless it is damaged and requires

separate the valve assembly from bellows unit (35).

repair or replacement. Attempt to extend bellows by

pulling on cross bar (27). If it moves easily, a leak is

(11) Remove four machine screws (47) on

present and the bellows must be reworked or replaced.

valve inlet and tube (34).

(3) Inspect valve disc (30). If seating surface

(12) Withdraw the valve inlet from lower

is scored, repair or replace disc.

housing (48).

(4) Replace packing in vacuum pump valve

(13) To separate bellows unit (35) from lower

(1) with 1/16-inch absestos yarn (2) and a lubricant such

housing in the vacuum -actuated chamber, place a

as vaseline when necessary.

blade of steel approximately 2 in. by 2 in. by 1/8 in.

thick between spacers (32). Be careful not to damage

(5) Replace any gaskets or O-rings which are

the lead pigtail.

not in good condition.

(14) Turn the bellows counterclockwise to

separate bellows unit (35) from lower housing.

NOTE

The key numbers shown below in

4-13. Cleaning

parenthesis refer to figure 4-11.

Clean all parts that come in contact with mercury as

follows:

m. Constant Vacuum Regulator, 6605306-5604,

Disassembly.

Perform the following steps to

a. Remove mercury from the barometer in

disassemble the constant vacuum regulator for

accordance with paragraph 4-5b.

utilization of authorized replacement parts:

b. Remove the cistern micrometer. Wipe the shaft

(1) On the upper housing, turn crank wheel

with a soft cloth or tissue and blow off lint and dust with

assembly counterclockwise until it bears against internal

clean compressed air. Place the micrometer in a clean,

stop.

safe place until time for reassembly.

No further

(2) Remove six machine screws (4) which

cleaning of the micrometer is necessary.

join the upper and lower housing. The O-ring preformed

c. Disassemble the barometer in accordance with

packing (21) should remain in the grooved ring of the

paragraph 4-12.

upper housing. Loosen the upper housing.

d. Place all metal parts in a stainless steel or glass

(3) Grasp upper housing (20) and turn it in a

tray containing cleaning compound such as alconoc,

counterclockwise direction. This will unscrew control

calgonite, oakite, or bonami (FSN 7930-243-5940, 7930-

spring assembly (17) from crossbar (27). Upper housing

5581111, or 7930-999-2417) and hot water.

(20) and lower housing (48) will separate.

e. Using brush FSN 7510-550-8446, scrub the

(4) To remove control spring(l7)from the

parts thoroughly.

upper housing, loosen round head screw (19) in split

locking nut (18) and remove the nut.

f. Using a small brush or pipe cleaner, swab out

connecting passage and screw holes in the base plate.

(5) Turn crank wheel (9) counterclockwise

Brush all screw threads thoroughly.

until the spring assembly is free of the housing.

g. Rinse all parts several times in hot

(6) To remove the crank assembly from the

housing, loosen machine screw (15) on split locking nut

(14), and remove the locking nut, facing washer (12),

4-28