GASKET 2S3527 - 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.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 flare connection.
Type 3 - Trapezoidal Ring Face Seal Connection (TRFS)
Illustration 3. Trapezoidal Ring Face Seal Connection (TRFS).
(4) Trapezoidal seal ring groove.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 is a better seal than the O-Ring face seal (ORFS) connection.
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 in Group 3.