Appendix A. DEMOUNTING AND REMOUNTING THE RT875CC SUPERSTRUCTURE

TM 55-3810-306-15

APPENDIX A

DEMOUNTING AND REMOUNTING THE RT875CC SUPERSTRUCTURE

A-1. Demounting the RT875CC superstructure includes

and horizontal. Remove the hook block and overhaul

removing forty 1-1/4-inch bolts, nuts and washers that

ball and rewind all rope on the hoist drums and stow the

secure the superstructure turntable swing bearing and ring

outrigger pads.

gear to the crane carrier deck plate. The crane swivel

2. With the superstructure rotated 4-1/2 to the

assembly must also be unbolted from the carrier and

right, from straight over front, four inner ring bearing bolts

suspended from and lifted off with the superstructure.

1, 2, 6, and 7 (figs 1 and 2) are visible through the

Disconnects for all fluid, air, and electric supply to the

elongated holes on each side of the turntable base plate.

superstructure are located at the lower end of the swivel

Mark these four bolts and do not remove them until all of

assembly, under the crane.

the following steps are completed.

3. Using crane power, the superstructure may now

CAUTION

be swung 18 to the right or left of the initial position in

Failure to demount the RT875CC

step 2 above, exposing pairs of unmarked bearing bolts

superstructure in the following step by

in the elongated holes on each side of the turntable base

step procedure could result in serious

plate. If the bolts on the left side, under the cab, can be

injury to personnel and/or damage to

reached with the available tool combination, begin by

the crane.

removing four bolts-3, 4, 8, and 9 or 34, 35, 39, and 40.

Continue incremental swings of 18in the same direction

A-2. Tools needed to demount the superstructure are

and remove all bolts, except 1, 2, 6, and 7, previously

included in the standard variety, normally available in

marked. If bolts are tight in holes after nut removal, tap

heavy-equipment maintenance facilities. Breaking the

out using a hammer.

1,965-foot-pound torque of the inner ring bearing bolts

4. Alternately, if a multiplier-torque wrench

may be accomplished with several different combinations

combination, air impact, or hydraulic wrench is to be

of tools, depending on availability:

used, and lacks vertical space on the left side under the

cab, all bolts may be removed through the elongated

1. A 28 to 1 multiplier plus a 30to 250-pound torque

holes on the right side of the turntable. Remove all bolts,

wrench, and 3/4-inch male to 1/2-inch female adapter.

except 1, 2, 6, and 7, in any sequence.

2. A 2,000-foot-pound torque wrench with handle

extensions as required.

CAUTION

When swinging boom over rear,

3. A 2,000-foot-pound-capacity impact wrench, if

shop air pressure is available.

during bearing bolt removal, raise the

boom enough to clear carrier

4. A 2,000-foot-pound hydraulic wrench, if auxiliary

structure so the operator can see to

hydraulic pressure is available. All of the above require a

the right side of the turntable.

1-7/8-inch socket with a compatible drive for the tool

selected. Also, a second 1-7/8-inch socket and handle,

open or box end wrench, is needed to hold the nut while

5. After all bolts except 1, 2, 6, and 7 are removed,

untorquing. Also, a socket set, up to 1-1/8-inch, is needed

swing the boom back to the initial, 4-1/2 to the right of

and material handling equipment and slings of at least

boom, straight over front position. (Bolts 1, 2, 6, and 7

53,000-pound-capacity to demount the superstructure and

are again exposed through the elongated holes in the

move the carrier. If the crane is to be transported,

turntable base plate.) If the vertical height of the tool

semitrailers or railroad flatcars of this capacity must also

combination prohibits removing bolts 6 and 7 from under

be supplied. Cribbing, planking, blocks, tiedown-chain

the cab on the left side of the turntable, break the torque

cables, straps, and so forth, must be onhand to stabilize

of these two bolts when the boom is to the right, straight

the removed superstructure on its transport vehicle or in

over rear position. Leave 6 and 7 snug until final

its stowed location.

removal as stated in the steps below.

6. Suitable material handling equipment as noted

Demount Procedure:

above must be used to demount the superstructure.

Using a four-fall sling with single apex positioned above

1. Position the crane on a flat, level surface,

the superstructure longitudinal

outriggers retracted, boom over front, retracted

A-1