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7

FIGURE 10 - 

EXPLODED VIEW

1

9

8

2

3

LOAD 

PISTON

4

10

5

11

12

FASTENER

RELAY PISTON

7

BODY

COVER

RESERVE 

SPRING

6

INSTALLATION

1.  Use the mounting bracket provided, or, if securing the 

valve to a reservoir, use a Schedule 80 (heavy wall) 
short couple pipe nipple.

2.  Reconnect all air lines to the valve using the 

identifi cation made during removal. Be sure to use pipe 
thread sealant.

3.  Test all air fi ttings for excessive leakage and tighten as 

needed. Also, perform OPERATIONAL AND LEAKAGE 
TESTS before placing the vehicle back into service.

DISASSEMBLY

The following procedure is for reference only. Always 
have the appropriate maintenance kit on hand, and use 
its instructions in lieu of those presented here. Refer to 
Figure 10 throughout.

CAUTION:

 The R-12P

 valve may be lightly clamped in 

a bench vise during disassembly. However, 
overclamping will cause damage to the valve 
and result in leakage and/or malfunction. If a 
vise is used, position the valve so the jaws 
bear on the supply ports on opposing sides 
of the valve’s body.

1.   Remove the four fasteners that secure the cover to the 

body. Then slowly remove the cover.

2.   Remove and discard the small o-ring(1) that seals the 

internal channel and the large o-ring(2) between the 
cover and the body.

3.  Remove the load piston from the cover. Note: If 

necessary, use approximately 20 psi of shop air, 
directed into the load piston’s air passage in the cover, 
to dislodge it. CAUTION: The piston will leave the cover 
with some force.

4.   Remove and discard the load piston’s o-ring(3).

5.   Remove the reserve spring and the relay piston from the 

body. Remove and discard the relay piston’s o-rings(4) 
and (5).

6.  While holding exhaust cover(7), remove and discard 

the snap ring(6) that secures the cover to the body.

7.   Remove and discard exhaust cover(7) and its o-rings(8) 

and (9).

8.   Remove and discard valve spring(10), valve retainer(11), 

and inlet/exhaust valve(12) from the body.

Содержание R-12P PILOT RELAY VALVE

Страница 1: ...en the valve s response time By balancing the pressure signal to all trailer and dolly brakes the R 12P valve aids in achieving overall vehicle brake pressure balance timing balance and stability It a...

Страница 2: ...nnel to the load piston Supply air builds simultaneously and equally underneath the inlet exhaust valve and above the load piston While supply pressure continues to hold the inlet exhaust valve agains...

Страница 3: ...the R 12P valve relay piston When air pressure beneath the piston approaches control pressure on top of the piston the piston and inlet valve lift together and close the inlet valve The exhaust remain...

Страница 4: ...r Figure 7 shows the control signal passing through the valve without causing piston movement The air is passing through the relay piston s equalizing orifice directly through the valve and out the de...

Страница 5: ...rce Control air also passes through the equalizing orifice and out the delivery port assuring no reduction or loss of control signal to subsequent vehicles Equalizing Slow Application If an equalizing...

Страница 6: ...ichever comes first for proper operation Should the valve not meet the elements of the operational tests noted in this document further investigation and service of the valve may be required SERVICE C...

Страница 7: ...e damage to the valve and result in leakage and or malfunction If a vise is used position the valve so the jaws bear on the supply ports on opposing sides of the valve s body 1 Remove the four fastene...

Страница 8: ...hread sealant before reuse ASSEMBLY 1 Before assembly lubricate all o rings seals and pistons as well as body and cover bores using the lubricant provided in the maintenance kit Use all of the lubrica...

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