ROD-CYLINDER 3979880 - Caterpillar

Illustration 1 g00806065
Illustration 2 g00811439
(1) Pressure gauge (2) Tester button (3) Adjustment knob for screed counterbalance To read the pressure of the screed counterbalance system, turn adjustment knob (2) to the ON position. Read pressure gauge (1) .An adjustable relief valve controls the hydraulic pressure to the screed counterbalance system. The pressure at the rod end of the screed lift cylinders should be 172 kPa (25 psi), when adjustment screw (3) is turned completely in the counterclockwise direction. The pressure will be indicated on pressure gauge (1) .Turn adjustment knob (3) clockwise in order to increase the pressure of the screed counterbalance system. Increase the pressure in 172 kPa (25 psi) increments in order to correct problems with the mat that are caused by the setting of the screed. Check the mat in order to determine that the desired results are being achieved after adjusting pressure of the screed counterbalance system.Note: If the pressure of the screed counterbalance system is increased above 1035 kPa (150 psi), the mat density may be affected. The mat density will have an open texture and the mat may require additional compaction from the compactor.Note: If the pressure of the screed counterbalance system is increased above 1035 kPa (150 psi), the automatic grade and slope controls may be affected. The higher pressure can cause the screed to not float and the higher pressure will affect the ability of the grade control to maintain the proper elevation. An indication of a high pressure setting is a grade that does not match the joint properly. A wavy mat can also result from the pressure that has been set improperly.