BRAKES 5-83
VACUUM PUMP
GENERAL DESCRIPTION
The vacuum pump is a rota ry, slid in g vane type pump
in which the ro to r is e c c e n tric a lly located with resp ect
to the housing.
The pump is dependent upon o il as a
means fo r lubrication of the b earin gs and also fo r p r o v i
ding a seal.
The vacuum pump is operated d ire c tly by a belt and
p u lley d riv e fro m the engine and operates at all tim es
w hile the engine is running. The lubrication of the pump
is accom plished by connection with the o il p ressu re s y s
tem of the engine.
Discharge of O il and A ir
The o il plus the a ir which enters through the vacuum
port, is disch arged through the housing just below the
point o f minimum ro to r to housing clearan ce. The o il
and a ir lea ves the pump through the opening on the pump
base which is connected to the engine crankcase by a
d isch arge hose.
D rive Pulley
Maxim um pump speed, fo r good life expectancy, is
4000 R PM . If it is n ecessary to rep la ce the d rive pulley,
be certain that c o r r e c t pu lley is used. If pulley diam eter
is too la rg e the pump capacity w ill be decreased; if the
pu lley is too sm a ll pump speed w ill exceed maximum r e
commended and prem atu re pump fa ilu re w ill result.
R e fe r to P a rts Catalogue fo r p ro p er replacem ent pulley.
SYSTEM TESTS
The fo llo w in g tests o r checks can be made on the
vacuum pump while it is operating.
Lubrication
A fte r the pump has been running fo r a few minutes,
check the o il and a ir discharge line near the pump d is
charge port. If the line is not w arm ing up, stop the pump
and check fo r re s tric tio n s in the o il supply line.
Vacuum
L e t the pump and engine operate at th eir norm al op er
ating speed fo r s e v e r a l minutes so as to w arm the o il
circu la tin g through the pump. Check the vacuum gauge.
The pump should maintain at lea st 26 inches of m ercu ry
vacuum. L et the engine idle. The pump should maintain
at lea st 20 inches of m ercu ry vacuum with the engine
idling. If the pump does not maintain the vacuum values
given above, inspect the pump fo r belt slippage o r lack
of lubrication. A ls o inspect the vacuum lin es and fittin gs
fo r leaks. If ve h ic le is not equipped with vacuum gauge,
te m p o ra rily connect one in intake line.
Binding in the Pump
A ft e r the pump has been running fo r s e v e ra l minutes,
stop the pump, loosen the b elt adjusting d evice and r e
m ove the belt. W ith the vacuum p ort o f the pump open to
atm osphere, rotate the pump in the d irection indicated on
the fron t end plate, and check fo r points at which the
pump tends to be binding. If binding occu rs, the pump
should be rem oved fro m the installation, disassem bled,
and inspected fo r faulty parts.
O il Leaks
A fte r the pump has been operating fo r s e v e ra l minutes,
inspect between the housing and the end plates fo r signs
o f o il leakage. T h is check should be made both with the
vacuum port open and closed to atm osphere.
V A C U U M PUMP REPLACEMENT
Removal (Fig. 137)
1. Loosen adjusting arm bolt and nut.
2. Loosen tension on d riv e belt and rem ove belt fro m
d riv e pulley.
3. Disconnect a ir intake hose.
4. Disconnect o il inlet hose.
5. Disconnect o il and a ir discharge hose.
6. R em ove four bolts which secure vacuum pump to
support base.
7. Rem ove pump and d isca rd gasket.
Installation
1. Position new gasket on pump base.
2. Position pump on base and secure with four bolts.
3. Connect o il and a ir disch arge hose.
4. Connect o il inlet hose.
5. Connect a ir intake hose.
6. Install b elt on d riv e pulley and pull to p ro p er tension
(120-130 pounds (new b elt) o r 90-100 pounds (used
belt) using a strand tension gauge placed at the
center o f the g rea test b elt span).
7. Tighten adjusting bolt and nut.
V A C U U M GAUGE
Some v eh icles c o vered in this manual have vacuum
gauges as standard equipment o r optional equipment. A ll
operate the sam e although they may d iffe r in appearance.
If a vacuum gauge is suspected of operating im p ro p erly
it may be checked by com paring readings with a test
gauge which is known to be accurate. O bserve readings
at variou s, s p e c ific engine speeds. In stall test gauge and
F ig . 137— Vacuum Pump
CHEVROLET TRUCK SERVICE MANUAL
Содержание 10 Series 1970
Страница 1: ......
Страница 38: ...HEATER AND AIR CONDITIONING 1A 8 CHEVROLET TRUCK SERVICE MANUAL...
Страница 57: ...HEATER AND AIR CONDITIONING 1A 27 Fig 35 Compressor M ountings CHEVROLET TRUCK SERVICE MANUAL...
Страница 75: ...HEATER AND AIR CONDITIONING 1A 45 Fig 65 R oof M ounted System W iring Diagram CHEVROLET TRUCK SERVICE MANUAL...
Страница 78: ......
Страница 101: ...BODY IB 23 s A ADJUSTER SCREW AND LEVER ASSY Fig 5 9 Exploded V iew o f Level Ride Seat CHEVROLET TRUCK SERVICE MANUAL...
Страница 137: ...BODY IB 59 VIEW IN DIRECTION OF ARROW A Fig 137 A u x ilia ry Seat CHEVROLET TRUCK SERVICE MANUAL...
Страница 142: ...CHEVROLET TRUCK SERVICE MANUAL Fig 5 10 30 Series Truck Frame FRAME 2 4...
Страница 145: ...CHEVROLET TRUCK SERVICE MANUAL FRAME 2 7...
Страница 148: ......
Страница 228: ...REAR SUSPENSION AND DRIVE LINE 4 52 I Fig 88 Forward Rear A xle Assembly Exploded V iew CHEVROLET TRUCK SERVICE MANUAL...
Страница 238: ......
Страница 383: ...ENGINE FUEL 6M 19 F ig I t Engine Fuel S p ecial Tools CHEVROLET TRUCK SERVICE MANUAL...
Страница 384: ......
Страница 392: ......
Страница 432: ...Fig 1 C lu tch Linkage Except P 2 0 4 0 Series...
Страница 433: ...CLUTCHES AND TRANSMISSIONS 7 3 Fig 2 C lutch Linkage Step Van P 20 40 Series CHEVROLET TRUCK SERVICE MANUAL...
Страница 506: ...FUEL TANK AND EXHAUST SYSTEMS 8 8 Fig 10 Vent Lines Cab M ounted Tanks CHEVROLET TRUCK SERVICE MANUAL...
Страница 528: ...Fig 31 T yp ica l Power Steering Hose Routings...
Страница 530: ......
Страница 550: ......
Страница 566: ...ELECTRICAL BODY AND CHASSIS 12 4 Fig 3 Front Lighting Assemblies CHEVROLET TRUCK SERVICE MANUAL...
Страница 567: ...ELECTRICAL BODY AND CHASSIS 12 5 Fig 4 C learance and Id e n tific a tio n Lamps CHEVROLET TRUCK SERVICE MANUAL...
Страница 568: ...ELECTRICAL BODY AND CHASSIS 12 6 Fig 5 Rear Lighting Composite CHEVROLET TRUCK SERVICE MANUAL...
Страница 597: ...ELECTRICAL BODY AND CHASSIS 12 35 Fig 37 Engine Com partm ent CE M E60 CHEVROLET TRUCK SERVICE MANUAL...
Страница 598: ...ELECTRICAL BODY AND CHASSIS 12 36 TO FRAME i f Fig 38 Engine Com partm ent C D 50 CHEVROLET TRUCK SERVICE MANUAL...
Страница 608: ...ELECTRICAL BODY AND CHASSIS 12 46 Fig 48 Instrument Panel C A40 CE CS ME50 Exc 02 CHEVROLET TRUCK SERVICE MANUAL...
Страница 610: ...ELECTRICAL BODY AND CHASSIS 12 48 Fig 50 Instrument Panel CE M E60 03 13 CHEVROLET TRUCK SERVICE MANUAL...
Страница 614: ...ELECTRICAL BODY AND CHASSIS 12 52 Fig 54 Instrument Panel SA40 50 CHEVROLET TRUCK SERVICE MANUAL...
Страница 628: ......
Страница 640: ......
Страница 649: ...SPECIFICATIONS 9 ENGINE SECTION 6 CHEVROLET TRUCK SERVICE MANUAL...
Страница 671: ......