MASSEY FERGUSON MF230 Shop Manual page 79

2 1 0 -212
Paragraphs
bracket, and can be removed afler
removing lifl cover as outlined in
paragraph 207.
To dt sasse m ble the dash pot, loosen ad·
justing screw (18-Fig. 195) and remove
adjustment rod (20) and spring (19). In·
vert the housing and remove plunger
(17), needle (15) and spring (14). Depress
piston rod and gu ide (8) and remove snap
ring (7), then remove spring (9), piston
(1 0) and spring (11). Expansion pi ugs or
guide (12) can be removed from body if
renewal i s indicated.
Assemble by reversing the di s assem·
bly procedure using Fig. 195 as a guide.
Ad just as outlined in paragraph 200
after tractor is assembled.
210. PRESSURE
VALVE AND DIAPHRAGM. The
pressure control valve shown exploded
Fig.
in 196 serves the dual purpose of
providing pressure relief for the main
hydraulic pump during normal opera·
tion and providing weight transfer for
added traction when using some types
of pulled or mounted implements.
Pressure line (2) is connected to weld·
ed tee-block in standpipe, and ram
cylinder pressure acts against. servo
is
piston (7) which is held closed by the
variable rat. e spring (3). The spring is
compressed the maximum when inner
to
quadt·ant control lever
CONTROL" or "CONSTANT PUMP­
ING" position, and is released at a
uniform rate as lever is moved to low
SS
end of "PRE URE CONTROL" sector
of quadrant. When pressure valve
rectly adjusted and operating properly,
pressure in the ram cylinder circuit
should be 140-275 kPa (20-40 psi) with
inner quadrant control lever at extreme
"LOW" end of quadrant and should in·
crease at. steady rate as lever is
n
moved, until the specified reliefpressut·e
is obtained as lever moves into "CONS­
TANT PUMPING" sector of Quadrant.
80
The servo piston (7) and matched
sleeve (8) connect the control dtaphragm
assembly (Fig. 197) to control
pressure valve. When servo piston is
against stop pin in valve body (9-Fig.
196) the diaphragm passage is open
open to reservoir. As pressure builds up
in lift cylinder circuit. and piston (7)
moves upward against. spring pressure,
CONTROL
in "POSITION
cor·
ts
Fig. 196-E'IIploded view of p,.ssure control valve.
I A<IJUI!ting tube
ssu
Pre
2 r e tube
3 Prell!lure apnng
6 Ptlol
6 Plunger
7 Cutde
8 &,at
Bod )
9
-
18�
_11
passage
- 9
10
I I
1 3
1 2
10 Val••
II
Spronw
12 Snop nn11
13 w ..
hcr
H
Spring
16 "o·· ra ng
l6 Ball
17 Boek up wn•hor
18 "0'' rani(
dashpot, control cover and
usocleted parts.
19
Fig. 195-Draft responn
J
Control CO\'tr
2 Rc��:pon,.,. lt-\lfr
3 i'ort plu11
4 S1de covt\r
5 Sprln�
8 O ran ro cam
7 Snep TlnK
Plun�o·r & bu•h•ng
8.
9 Spron11
10 Olt•hpot p••w n
II Spnn11
12 Cu•clt
13 Oa•hpot
Spnna
14
15 Reoponk n<t'dl�
17 Val•e plun�!ef
18. A<IJusung "'"""
19 Sprona
20 NL-t-dlt'
MASSEY -FERGUSON
the diaphragm exhaust passage is
closed. When the pressure Jjmit is
of reached, fluid passes servo piston to
diaphragm passage, extending the
diaphragm plunger to move the main
hydraulic pump control arm to neutral.
to
Relief valve ( 10) is preset at a slightly
higher pressure than diaphragm return
spring (2-Fig. 197). The valve provides
a safety relief passage if diaphragm
plunger malfunctions or system
properly adjusted.
To disassemble the pressure control
valve, refer to Fig. 196 and proceed as
follows: Withdraw adjusting
sprmg (3), then unscrew and remove
pilot (5). Using needlenose pliers,
carefully withdraw guide
piston seat (8) using a hooked wire.
Relief valve (10) and spring (11) can be
removed after removing snap ring (12).
Guide (7) and seat (8) ate available on­
ly as a matched set. All other parts are
available individually. Examine all
parts carefully and renew any which
worn, scored or damaged.
Assemble the pressure control valve
by reversmg the di
sasse
Adjust as outlined in paragraph 199
after lift cover is reinstalled.
211. INTERNAL UNKAGE AD­
JUSTMENT. The following internal lin.
linkage adjustments must be performed
before reinstalling lift cover. lnvert the
lift cover in a fixture or on a bench.
Block up the cover as necessary so
rockshaft can be moved to the normal
raised "TRANSPORT" position.
Check and adjust master control
spring (5-Fig. 192) as outlined in
paragraph 194. Make sure draft control
rod does not contact spring plunger
when adjusting master control spring.
Move draft control lever to fully lowered
position on quadrant and, if
place a wedge between lift cover casting
and draft control rod adjusting
AFT
212. DR CONTROL ROD. To ad­
just drafl control rod (6-Fig. 198), first
move drafl control lever
Fig. 197-E'II p loded view of pressure control
dlaphregm.
im­
i s
tube (1) and
(7).
Remove
are
m bly procedure.
necessary,
screw.
full "UP"
to
3. Otaphra�m
4.
Body