Lafayette 3612 Engine BBHMM00 - Caterpillar

Illustration 1 g06194599
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) Travel motor (right)
(17) Travel motor (left)
(18) Swing motor
Table 1
Relief Valve Specifications Torque for Locknut
New
Rebuilt(1) Service Limit(2)
Main relief valve 35000 + 500 - 1000 kPa (5076 + 73 - 145 psi) 35000 + 500 - 2000 kPa (5076 + 73 - 290 psi) 50 10 N m (37 7 lb ft)
Main relief valve (Heavy Lift) 38000 + 500 - 1000 kPa (5512 + 73 - 145 psi) 38000 + 500 - 2000 kPa (5512 + 73 - 290 psi) 69 10 N m (51 7 lb ft)
Boom cylinder line (head end) 41000 500 kPa (5947 73 psi) 32800 kPa (4757 psi)
( 35800 kPa (5192 psi) Heavy Lift) 20 2 N m (14 1 lb ft)
VA Boom cylinder line (head end)
Boom cylinder line (rod end) 38000 500 kPa (5511 73 psi) 32800 kPa (4757 psi)
VA Boom cylinder line (rod end)
Stick cylinder line (head end)
Stick cylinder line (rod end) 41000 500 kPa (5947 73 psi) 32800 kPa (4757 psi)
( 35800 kPa (5192 psi) Heavy Lift)
Bucket cylinder line (head end) 38000 500 kPa (5511 73 psi) 32800 kPa (4757 psi)
Bucket cylinder line (rod end)
Swing relief pressure (right) 25500 1000 kPa (3698 145) 25500 + 1000 - 2000 kPa (3698 + 145 - 290 psi) 117 10 N m (85 7 lb ft)
Swing relief pressure (left)
Left travel crossover relief valve (forward) 37000 500 kPa (5366 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 pressure reducing valve 4100 300 kPa (595 44 psi) 9.5 1 N m (84 9 lb in)
(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 14400 kPa (2100 psi)
Line relief valve 24000 kPa (3480 psi)
Swing relief valve 6800 kPa (985 psi)
Travel crossover relief valve 3050 kPa (440 psi)
Pilot pressure reducing valve 11000 kPa