REMOVAL - TM-10-3930-607-150214

UPRIGHTS

until the pilot is out of the pilot hole in the mounting pad.

In operation, oil enters the bottom of the hoist cylinder,

by-passes the bottom bushing on the primary rod, then

travels upward in the cavity between the outer shell and

NOTE:

primary rod tot the packing at the top of the cylinder.

It may be necessary to push in on the top

and pull out on the bottom of the cylinder

As pressure increases, the primary rod is forced out of

during lifting, in order to clear the fitting on

the outer shell, carrying the secondary rod with it.

the base of the cylinder.

Not until the primary rod is fully extended does the

C. DISASSEMBLY (Fig. 17)

hydraulic pressure force the se<ondary rod out. When

this happens, air, which is between the primary and

NOTE:

secondary rods, is forced into a passage to the center of

If only the seals and packing are to be

the secondary rod. The passage is in the plug at the

replaced, the entire cylinder assembly need

bottom of the rod.

not be disassembled.

During lowering, the primary rod enters the outer shell

1. With the cylinder in a horizontal position, pull the

before the secondary rod is forced into the primary rod.

secondary rod out of the primary rod. Support the

If the lowering speed becomes too fast, the lowering

crosshead end of the rod.

control valve is acted upon to restrict the flow of oil

leaving the cylinder. Consequently, the lowering speed

NOTE:

is limited to a safe speed.

A strap attached to the top of the secondary

rod will aid in extracting the rod.

The lowering control valve is attached to the high

pressure port in the base.

2. Using a spanner wrench, unscrew the bushing

and seal assembly from the primary rod. Then, extract

B. REMOVAL

the secondary rod.

1. Remove the carriage.

3. Support the secondary rod on both ends, being

careful not to damage the packing assembly or the

2. Raise and block the front of the truck high

chromed surface.

Slide the spacer rings, if so

enough to enable the removal of the lowering control

equipped, off the top end of the rod, and remove the

valve. Disconnect the two hydraulic hoses front the

spiral lock from the bottom. Pull the piston and

bottom of the cylinder. Remove the lowering control

packing off together.

valve. Cap all hydraulic openings.

NOTE:

3. Attach a hoist slightly above the middle of the

If only the primary rod packing is to

cylinder shell, and remove the slack from the slinging.

be serviced, it is not necessary to

Remove chain adjusting nuts from the bottom of the

remove the base.

cylinder. Pull the anchors out of the base.

4. Push the primary rod toward the top about two

Unscrew the four capscrews securing the

inches. Remove dirt, nicks and burrs from the top of the

crosshead to the secondary rod. Secure the crosshead

primary rod. Pull the rod out of the bottom of the shell,

and guide assembly in a position above the cylinder.

being careful not to drag the rod over the inside surface

of the shell.

5. Gradually lift the cylinder from the mounting pad,

B-178