Section III. TRAILER FRAME AND BED REPAIRS

12.

jackscrew

KEY to figure ,-6:

13.

Lock jam nut. 3/4-16

14.

Washer, 3/4 std.

1. Round head screw

15.

jackscrew key

2. Top cover

16.

Jackscrew bushing

3. Groove-pin 5/ 16 dia. x 9/16 inch

17.

Thrust bearing

4. Cross shaft gear

18.

Bearing washer

5. Cross shaft R. H. outside mount

19.

Hex head bolt. 5/ 8-11

6. Cross shaft L. H. outside mount

20.

Locknut 5/ 8-11

7. Two speed gear, cross shaft

21.

Landing gear cross brace

8. Groove pin, 3/8 in. dia. x I 1/ 2 in. Ig.

22.

Landing gear brace

9. Shalt bushing

23.

Right hand leg upper housing

10. Detent assembly

24.

Left hand land gear assembly

11. Jack screw gear

Section III. TRAILER FRAME AND BED REPAIRS

c. King Pin Fifth Wheel Assembly. Weld new king

7- 16. General

pin to new fifth wheel plate per paragraph 7-17 b. and

The trailer frame and bed is specially designed and built

figure 7-7.

to support and transport the mobile substation. Due to its

construction the following items and assemblies are

CAUTION

considered repairable or replaceable; landing gear braces,

trap door assemblies, mud flap assembly, rear bumper

The location of the king pin is critical. Its

assembly king pin fifth wheel plate assembly,

position on trailer in relation to the front axle

undercarriage frame assembly and trailer deck.

of wheels affects towing quality .

7-17. Weldments

a. Removal of Welded Members. The method used

d. King Pin Fifth Wheel Assembly Installation.

to separate welded members is dictated by the situation

Locate assembly on trailer as shown in figure 7-7. Clamp

and which member if not both, is being replaced. Care

in position and check position dimensions for location,

must be taken 80 as not to damage remaining members

reposition if necessary, or weld in place if correct.

to be reused.

b. Welding. Weld all joints per Mil-Spec.1261.

7-20. Under carriage Assembly Frame

c. Painting. Prime with metal primer per MILP858.

Paint with two coats of Semi-Gloss Olive Drab X24087

a. General. The undercarriage frame alignment is

(Federal Standard 595A) per MIL Std.-193.

important because it supports the suspension and wheel

assembly. The alignment affects the towing qualities of

7-18. Landing Gear Braces Repair

the trailer. Before straightening bent members all weld

a. Replacement. The braces are made from steel

joints should be inspected for cracks or tears. If joints are

tubing. Therefore, if bent it is best to replace them rather

damaged they should be cut. Bent parts should be

than straighten.

straightened or replaced. Use procedures outlined in

b. Installation. Install new brace with new hex head bolts

paragraph 717 a and 7-17 b

5/8-11 NC x 11/4 and 5/ 8-11 hex lock nuts at each end of

brace.

b. Suspension Mounts. When wheel suspension

7-19. King Pin Fifth Wheel Replacement

hangers are damaged they should be replaced. Use

a. General. To replace a damaged king pin a new

procedures in paragraph 7-17 a and 7-17 b for removal

and welding.

fifth wheel plate is needed. The wheel plate must be

removed and a new king pin fifth wheel plate assembly

installed.

7-21. Trailer Deck Repair Replacement

b. Fifth Wheel Plate Removal. Cut weld securing

fifth wheel plate to trailer per paragraph 7-17 a.

The deck is made of two 1/4 inch thick steel plates. The

front plate is 10 feet long by 95 3/8 inches wide' the rear

plate is 20 feet long by 95 7/8 inches wide. If deck is

damaged to the point of repair, sections can be replaced.

By inspection of supporting members it can be

determined at what point a damaged area may be cut out

and replaced.

7-13