Jeep UNIVERSAL CJ-2A - Page 78

'Jeep' UNIVERSAL and 'Jeep' DISPATCHER
pressure. To disassemble the pump, Fig; 96, first
remove the gear which is retained by straight
pin. It will be necessary to file off one enu of the
pin before driving it out with a small drift. By re-
moving the cover the outer rotor arid the inner
rotor and shaft may be rem~yed through, the
cover opening. Failure of the pump to operate .at
full efficiency may usually be traced to excessive
end float of the rotors or excessive clearance be-
tween the rotors. The clearance between the outer
rotor ·and the pump body should also be ·checked.
Match the rotors together with one lobe of the inrier
rotor pushed as far as possible into the notch of the
outer rotor. Measure the clearance between the
lobes of the rotors as shown in Fig. 97. This clear-
ance should be .010
11
• [0,254 mm.] or less.
If more, replace both rotors. Measure the clearance
between' the outer rotor and· the pump body as
shown in Fig. 98. Should this clearance exceed
,012" [0,305 ·mm.] the fault is probably in the
pump body and it should be replaced. End float
of the rotors is controlled by the thickness of the
cover gasket which is made of special material that
can be only slightly compressed. Never use other
than a standard factory gasket. Check the cover
to be sure the inner surface is not rough or scored
and that it is :flat within .001
11
[0,025 mm.] tested
with feeler gauges, Fig. 99 .. . Measure thickness of
the rotors which musfbewithin .001
11
of each other.
Assemble the rotors in the pump body and install
the cover without the ,gasket. When the cover
screws are tightened to normal tension, there
should be interfer.ence between the rotors and the
cover making it impossibleto turnthe pump s~ft
by hand. Remove the cover and replace it with
the gasket in position. The rotors sh<;mld then
rotate freely, proving that end float of the rotors
is less than the thickness ofthe gasket when com-
FIG. 97.:__CHECKING OIL PUMP ROTORS
pressed or .004
11
[0,102 mm.]. After assembling
the gear on the pump shaft, check the running
clearance between the gear and pump body with a
feeler gauge.
This clearance should be from .022
11
to .051
11
[0,559 a 1,295 mm.].
Pump output is controlled by a pressure relief
valve.
CAUTION: The oil pressure relief spring is cali-
brated. Never stretch this spring to alter the relief
valve • pressur~ setting .. Adju,st this setting by the
use of shims only. Shims are available that can be
added between the retahier and the spring tq ,in-
. crease;'pressure. W'.hen shims are present, removing
shims will decrease pressure. ·
FIG. 98-'-CHECKlNG OUTER ROTOR TO
OIL PUMP BODY
FIG. 99-CHECKING OIL PUMP COVER
This adjustment will change the pressure at higher
speeds but not at idle speed. Safe minimum pres-
sure is 6 psi. [0,4 kg-cm2] at idle, at which point
the oil pressure light· goes out; and 20 psi. [1 ,4
kg-cm2]
at 2000 rpm. (32 mph. [51 kph.]).
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