330C Excavator Hydraulic System Caterpillar

Specifications

Usage:

330C MSD

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Illustration 1	g00721434
Relief valve locations (A) Main relief valve (B) Boom cylinder line (head end) (C) Boom cylinder line (rod end) (D) Stick cylinder line (head end) (E) Stick cylinder line (rod end) (F) Bucket cylinder line (head end) (G) Bucket cylinder line (rod end) (H) Swing (right) (I) Swing (left) (J) Left travel crossover relief valve for forward travel (upper valve) (K) Left travel crossover relief valve for reverse travel (lower valve) (L) Right travel crossover relief valve for forward travel (upper valve) (M) Right travel crossover relief valve for reverse travel (lower valve) (N) Pilot relief valve (O) Main control valve (P) Pilot filter (Q) Travel motor (right) (R) Travel motor (left) (S) Swing motor

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Table 1
Relief Valve	Specifications		Torque for Locknut	CHS Inspection Step Number ⁽¹⁾
Relief Valve	New Rebuilt ⁽²⁾	Service Limit ⁽³⁾	Torque for Locknut	CHS Inspection Step Number ⁽¹⁾
(A) Main relief valve	34300 ± 500 kPa (4950 ± 75 psi)	32400 to 34800 kPa (4700 to 5050 psi)	50 ± 10 N·m (37 ± 7 lb ft)	115
(B) Boom cylinder line (head end)	37200 ± 1000 kPa (5400 ± 150 psi)	34700 to 38200 kPa (5030 to 5540 psi)	20 ± 2 N·m (14 ± 1 lb ft)	138
(C) Boom cylinder line (rod end)
(D) Stick cylinder line (head end)				136
(E) Stick cylinder line (rod end)				134
(F) Bucket cylinder line (head end)	36800 ± 1500 kPa (5350 ± 215 psi)	33800 to 38300 kPa (4900 to 5550 psi)		140
(G) Bucket cylinder line (rod end)	36800 ± 1500 kPa (5350 ± 215 psi)	33800 to 38300 kPa (4900 to 5550 psi)		142
(H) Swing relief pressure (right)	29400 ± 1000 kPa (4250 ± 150 psi)	27500 to 30400 kPa (4000 to 4440 psi)	120 ± 10 N·m (85 ± 7 lb ft)	147
(I) Swing relief pressure (left)	29400 ± 1000 kPa (4250 ± 150 psi)	27500 to 30400 kPa (4000 to 4440 psi)	120 ± 10 N·m (85 ± 7 lb ft)	145
(J) Left travel crossover relief valve (forward)	36300 ± 1470 kPa (5250 ± 215 psi)	33800 to 38300 kPa (4900 to 5550 psi)	90 ± 10 N·m (70 ± 6 lb ft)	151
(K) Left travel crossover relief valve (reverse)				154
(L) Right travel crossover relief valve (forward)				157
(M) Right travel crossover relief valve (reverse)				160
(N) Pilot relief valve	4100 ± 200 kPa (595 ± 29 psi)		50 ± 5 N·m (36 ± 4 lb ft)	50

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^( 1 )	Custom Hydraulic Service (CHS) is a preventive maintenance program for the machine hydraulic system. CHS is also a valuable part of any Customer Support Agreement. Refer to Custom Hydraulic Service, REHS1780.
^( 2 )	A New specification is the performance that can be expected for a new machine. A "Rebuild" specification is the performance that can be expected after rebuilding the components of a system.
^( 3 )	Performance beyond "Service Limit" specifications is an indication of the following problems: improper adjustment , wear , damage of relief valves and damage of pumps.

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Table 2
Cycle Times (seconds)
Function	Factory	CHS Inspection Step Number ⁽¹⁾
Boom EXTEND	3.5 ± 0.5	192
Boom RETRACT	2.4 ± 0.5
Stick EXTEND	3.0 ± 0.5	195
Stick RETRACT	2.6 ± 0.5	197
Bucket EXTEND	3.9 ± 0.5	199
Bucket RETRACT	2.3 ± 0.5	201
Swing LEFT (180°)	4.0 ⁽²⁾	208
Swing RIGHT (180°)	4.0 ⁽²⁾	208
Overswing LEFT	1200 mm (47.2 inch) ⁽²⁾	209
Overswing RIGHT	1200 mm (47.2 inch) ⁽²⁾	209
Forward travel HIGH (Left) (3 revolutions)	15.0 ⁽²⁾	217
Reverse travel HIGH (Left) (3 revolutions)	15.0 ⁽²⁾
Forward travel LOW (Left) (3 revolutions)	23.5 ⁽²⁾
Reverse travel LOW (Left) (3 revolutions)	23.5 ⁽²⁾
Forward travel HIGH (Right) (3 revolutions)	15.0 ⁽²⁾	218
Reverse travel HIGH (Right) (3 revolutions)	15.0 ⁽²⁾
Forward travel LOW (Right) (3 revolutions)	23.5 ⁽²⁾
Reverse travel LOW (Right) (3 revolutions)	23.5 ⁽²⁾

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^( 1 )	Custom Hydraulic Service (CHS) is a preventive maintenance program for the machine hydraulic system. CHS is also a valuable part of any Customer Support Agreement. Refer to Custom Hydraulic Service, REHS1780.
^( 2 )	Maximum

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Table 3
Cylinder Drift
Function	Factory	CHS Inspection Step Number ⁽¹⁾
Boom cylinder	6.0 mm (0.24 inch)	228
Stick cylinder	10.0 mm (0.39 inch)	228
Bucket cylinder	10.0 mm (0.39 inch)	237

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^( 1 )

Custom Hydraulic Service (CHS) is a preventive maintenance program for the machine hydraulic system. CHS is also a valuable part of any Customer Support Agreement. Refer to Custom Hydraulic Service, REHS1780.

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Table 4
Required Tools
Part Number	Description	Qty
9U-7400	Multitach Tool Group	1
8T-0470	Thermometer group	1

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Table 5
Relief Valves	Pressure change With One Turn Of Adjustment Screw
Main valves	14400 kPa (2100 psi)
Line relief valve	11000 kPa (1600 psi)
Swing relief valve	6800 kPa (985 psi)
Travel crossover relief valve	3050 kPa (440 psi)
Pilot relief valve	620 kPa (90 psi)

Note: Pressure values in Table 6 are approximate values. Use a pressure gauge for adjustment.

Note: Normal operations of the engine and pumps are necessary for the pressure adjustments. If the results of the pressure adjustment are not correct, then the engine and the pump characteristic curve needs to be checked. Slow output flow from the pump is an indication of air in the hydraulic system. Make sure that no air is present in the hydraulic system. Refer to Testing And Adjusting, "Main Hydraulic Pump Air - Purge".