DOWEL 4F6011 - Caterpillar

Type 1 - 37° Flare
Illustration 1. 37° Flare Connection. (1) 37° flare on male connection. (2) 37° flare on female connection.The 37° flare on male connection (1) seats on the 37° flare of female connection (2). No rubber seal is used in this connection.
Type 2 - O-ring Face Seal Connection (ORFS)
Illustration 2. O-ring Face Seal Connection (ORFS). (3) O-ring groove. (A) Groove cross section. (B) O-ring cross section.The O-ring face seal (ORFS) is also used for sealing pressure oil. An O-ring fits in O-ring groove (3) and seals against the flat surface of the female connection. This connection provides a better seal than the 37° flare connection.
Type 3 - Trapezoidal Ring Face Seal Connection (TRFS)
Illustration 3. Trapezoidal Ring Face Seal Connection (TRFS). (4) Trapezoidal seal ring groove. (C) Groove cross section. (D) Seal cross section.The trapezoidal ring face seal is used for sealing pressure oil. A ring fits in trapezoidal seal ring groove (4) and seals against the flat surface of the female connection.
This connection provides for easier assembly to the person who is securing the connection. The trapezoidal ring will stay seated in the groove correctly if the seal groove is facing down during the assembly procedure.
Three sizes of the trapezoidal seal are used in 311, 312 and 320 Excavators. The three seals have different inner diameters, but have the same cross-section geometry. Part numbers for the seals are 4I-8888, 4I-8889, and 4I-8891.
The trapezoidal seal is used with a unique seal groove. But, the TRFS male connector with the trapezoidal seal has the same interchangeability as the ORFS male connector with the O-ring seal. Both the TRFS connector and the ORFS connector can be assembled using the same female connector.
Type 4 - Split Flange Connection
Illustration 4. Split Flange Connection. (5) O-ring groove. (6) Flange halves.The split flange connection is used for sealing pressure oil. An O-ring fits in O-ring groove (5) and seals against the flat surface of the other half of the connection. The connection is held together by two flange halves (6). The connection is used for nominal sizes of one inch or bigger.
Hydraulic Lines
The hydraulic lines of an excavator can be classified into the following four groups:
Group 1 (Low pressure pilot lines)
Pilot lines and pilot drain lines are in this group. The maximum pressure in these lines is 3450 kPa (500 psi).
Group 2 (High pressure pilot lines)
This group includes two pilot lines that get pressure oil from the main pumps. Also in this group are negative flow control pilot lines that can withstand pressures up to 20600 kPa (3000 psi). Another in this group is the line connecting the shuttle valve in the main pumps to the ON-OFF port of the automatic speed change valve. This line can withstand pressures up to 34300 kPa (5000 psi).
Group 3
This group includes the main hydraulic lines on the upper plates of the boom and stick. These lines provide pressure to the bucket and stick cylinders.
Group 4
This group includes most of the main hydraulic lines that are not