345B Excavator Hydraulic System Caterpillar

Pressure Specifications

Usage:

345B 2NW

Specifications

Note: 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. Performance beyond Service Limit specifications is an indication of these problems: improper adjustment, wear, damage of relief valves and damage of pumps.

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Illustration 1	g00479607
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) Right swing motor (right relief valve) (I) Right swing motor (left relief valve) (J) Left swing motor (right relief valve) (K) Left swing motor (left relief valve) (L) Left travel crossover relief valve for forward travel (upper valve) (M) Left travel crossover relief valve for reverse travel (lower valve) (N) Right travel crossover relief valve for forward travel (upper valve) (O) Right travel crossover relief valve for reverse travel (lower valve) (P) Pilot relief valve (Q) Cooling pump relief valve (R) Counterweight cylinder (S) Right swing motor (T) Left swing motor (U) Pilot manifold (V) Travel motor (right) (W) Travel motor (left)

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Table 1
Relief Valve	Specifications			Torque For Locknut
Relief Valve	New	Rebuild	Service Limit	Torque For Locknut
(A) Main relief valve	34300 ± 490 kPa (4975 ± 72 psi)	34300 ± 490 kPa (4975 ± 72 psi)	32340 to 34790 kPa (4690 to 5045 psi)	50 ± 10 N·m (37 ± 7 lb ft)
(B) Boom cylinder line (head end)	36800 ± 1470 kPa (5350 ± 215 psi)	36800 ± 1470 kPa (5350 ± 215 psi)	33850 to 38270 kPa (4910 to 5550 psi)	20 ± 2 N·m (14 ± 2 lb ft)
(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) Right swing motor (right relief valve)	34100 ± 980 kPa (4950 ± 140 psi)	34100 ± 980 kPa (4950 ± 140 psi)	32740 to 35080 kPa (4750 to 5100 psi)	44 ± 5 N·m (32 ± 4 lb ft)
(I) Right swing motor (left relief valve)	34100 ± 980 kPa (4950 ± 140 psi)	34100 ± 980 kPa (4950 ± 140 psi)	32740 to 35080 kPa (4750 to 5100 psi)
(J) Left swing motor (right relief valve)	29400 ± 980 kPa (4270 ± 140 psi)	29400 ± 980 kPa (4270 ± 140 psi)	27440 to 30380 kPa (3980 to 4400 psi)
(K) Left swing motor (left relief valve)	29400 ± 980 kPa (4270 ± 140 psi)	29400 ± 980 kPa (4270 ± 140 psi)	27440 to 30380 kPa (3980 to 4400 psi)
(L) Left travel crossover relief valve (forward)	36800 ± 1470 kPa (5350 ± 215 psi)	36800 ± 1470 kPa (5350 ± 215 psi)	33850 to 38270 kPa (4910 to 5550 psi)	130 ± 13 N·m (95 ± 10 lb ft)
(M) Left travel crossover relief valve (reverse)
(N) Right travel crossover relief valve (forward)
(O) Right travel crossover relief valve (reverse)
(P) Pilot relief valve	4400 to 4890 kPa (650 to 720 psi)	4400 to 4890 kPa (650 to 720 psi)	4400 to 4890 kPa (650 to 720 psi)	16 ± 1 N·m (12 ± 1 lb ft)
(Q) Cooling pump relief valve	17200 ± 490 kPa (2490 ± 71 psi)	17200 ± 490 kPa (2490 ± 71 psi)	17200 ± 490 kPa (2490 ± 71 psi)	60 ± 6 N·m (44 ± 4 lb ft)
(R) Counterweight cylinder	15100 + 300 - 0 kPa (2190 + 44 - 0 psi)	15100 + 300 - 0 kPa (2190 + 44 - 0 psi)	15100 + 300 - 0 kPa (2190 + 44 - 0 psi)	30 ± 2 N·m (22 ± 1 lb ft)

Adjustment Procedures

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Table 2
Required Tools
Part Number	Description	Qty
6V-4161	Hydraulic Testing Group	1
8T-0470	Thermometer Group	1
JERD2129	Data Subscription for Electronic Technician	1
7X-1570	Data Communication Line for Electronic Technician	1
7X-1700	Communications Adapter for Electronic Technician	1
7X-1488	Cable for 7X-1701 to PC Communications Port	1

Note: Use Electronic Technician (E.T.) to monitor engine speed in the following procedures.

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Table 3
Relief Valves	Pressure change With One Turn Of Adjustment Screw
Main valves	14400 kPa (2100 psi)
Line relief valve	12100 kPa (1750 psi)
Swing relief valve	10000 kPa (1450 psi)
Travel crossover relief valve	10000 kPa (1450 psi)
Pilot relief valve	690 kPa (100 psi)

Preparation For Relief Valve Adjustment

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Illustration 2	g00299598
Pump compartment (1) Pressure tap (power shift pressure) (2) Pressure tap (upper pump delivery pressure) (3) Pressure tap (lower pump delivery pressure)

Position the machine on level ground.

Stop the engine.

Release the pressure in the hydraulic system. Refer to Testing And Adjusting, "Hydraulic System Pressure - Release".

Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (2) . Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (3) .

Connect a 4000 kPa (580 psi) pressure gauge to pressure tap (1) .

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Illustration 3	g00299600
Location of service connector (24) Data communication line for Electronic Technician (25) Service connector

Connect data communication line for Electronic Technician (24) to service connector (25) .

Start the engine.

Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).

Place the machine controls at the following settings: Power Mode, engine speed dial "10" and AEC switch OFF.

Note: The engine will not reach maximum no-load speed until the hydraulic tank pressure has reached the operating level.

ReferenceMake reference to Testing And Adjusting, "Operational Checks" for engine rpm settings.

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, "Hydraulic System Pressure - Release".