BELT-SERPENTINE 3748495 - Caterpillar

Illustration 1 g02265295
Relief valve locations
(1) Main relief valve
(2) Boom cylinder line (head end)
(3) Boom cylinder line (rod end)
(4) Stick cylinder line (head end)
(5) Stick cylinder line (rod end)
(6) Bucket cylinder line (head end)
(7) Bucket cylinder line (rod end)
(8) Swing (right)
(9) Swing (left)
(10) Left travel crossover relief valve for forward travel (upper valve)
(11) Left travel crossover relief valve for reverse travel (lower valve)
(12) Right travel crossover relief valve for forward travel (upper valve)
(13) Right travel crossover relief valve for reverse travel (lower valve)
(14) Pilot relief valve
(15) Main control valve
(16) Pilot filter
(17) Travel motor (right)
(18) Travel motor (left)
(19) Swing motor
Table 1
Relief Valve Specifications Torque for Locknut
New
Rebuilt(1) Service Limit(2)
Main relief valve 35000 500 kPa (5076 73 psi) 35000 + 500 - 2000 kPa (5076 + 73 - 290 psi) 50 10 N m (37 7 lb ft)
38000 500 kPa (5512 73 psi)
(Heavy Lift) 38000 + 500 - 2000 kPa (5512 + 73 -290 psi) 69 10 N m (51 7 lb ft)
Boom cylinder line (head end) 40000 500 kPa (5802 73 psi) 32800 kPa (4757 psi) 20 2 N m (14 1 lb ft)
Boom cylinder line (rod end) 37000 500 kPa (5366 73 psi) 32800 kPa (4757 psi)
Stick cylinder line (head end)
Stick cylinder line (rod end) 40000 500 kPa (5802 73 psi) 32800 kPa (4757 psi)
Bucket cylinder line (head end) 37000 500 kPa (5366 73 psi) 32800 kPa (4757 psi)
Bucket cylinder line (rod end)
Swing relief pressure (right) 334-9970 Swing Motor Gp 26400 1000 kPa (3829 145 psi) 26400 1000 kPa (3829 145 psi) 118 10 N m (87 7 lb ft)
Swing relief pressure (left) 334-9970 Swing Motor Gp
Swing relief pressure (right) 482-6393 Swing Motor Gp 27300 1000 kPa (3960 145 psi) 27300 + 1000 - 2000 kPa (3960 + 145 - 290 psi)
Swing relief pressure (left) 482-6393 Swing Motor Gp
Left travel crossover relief valve (forward) 37500 500 kPa (5439 73 psi) 32800 kPa (4757 psi) 92 8 N m (68 6 lb ft)
Left travel crossover relief valve (reverse)
Right travel crossover relief valve (forward)
Right travel crossover relief valve (reverse)
Pilot relief valve 4100 200 kPa (595 29 psi) 49 5 N m (36 4 lb ft)
(1) 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.
(2) Performance beyond “Service Limit” specifications is an indication of the following problems: improper adjustment, wear, damage of relief valves and damage of pumps.
Table 2
Relief Valves Pressure change With One Turn Of Adjustment Screw
Main valves 14500 kPa (2103 psi)
Line relief valve 19800 kPa (2872 psi)
Swing relief valve 6800 kPa (985 psi)
Travel crossover relief valve