BobCat 753 – CYLINDER (POWER BOB-TACH) – Assembly

Use the following tools to assemble the cylinder:

MEL 1396 – Seal Installation Tool
MEL 1033 – Rod Seal Installation Tool
Piston Ring Compressor
Spanner Wrench

Wash the cylinder parts in solvent and air dry them.

Inspect the cylinder parts for nicks, scratches or other damage. Replace any damaged parts.

Always install new O-rings and seals during assembly.

Lubricate all O-rings and seals with hydraulic oil during installation.

Install the new seal on the tool and slowly stretch it until it fits the piston [Figure 20-22-9].

Allow the seal to stretch for 30 seconds before installing it on the piston.

Piston: Install the O-ring (Item 1) and seal (Item 2) on the piston (Item 3) [Figure 20-22-10].

NOTE: The piston center hole (Item 4) [Figure 20-22-10] has a bevel on one end. The bevel goes toward the rod.

Install the rod seal on the rod seal tool [Figure 20-22-11].

NOTE: During installation the O-ring side of the seal must be toward the inside of the cylinder.

Rotate the handles to collapse the rod seal [Figure 20-22-12].

Install the rod seal in the head [Figure 20-22-13].

Install the wiper seal with the wiper toward the outside of the head.

Install the thin O-ring (Item 1) [Figure 20-22-14].

Install the back-up washer (Item 2) and thick O-ring (Item 3) [Figure 20-22-14] into the groove on the head.

NOTE: Clean and dry the threads before installing the nut. Install the new nut from the seal kit.

Install the head (Item 1), and spacer (Item 2) [Figure 20-22-15].

Install the piston (Item 3) [Figure 20-22-15].

Lift Cylinder: Grease the piston where the nut contacts the piston, do not get grease on the threads. Install the
new nut (Item 4) [Figure 20-22-15].

Tighten the nut to 90 ft.-lbs. (122 Nm) torque.

Put the base end of the hydraulic cylinder in a vise.

Tighten the head using a spanner wrench [Figure 20-22-16].


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