Towing With Wrecker Crane.
.WARNING.
• If vehicle being towed has inoperative compressed air system,
emergency air and service air lines must not be connected
between vehicles. Failure to do this may result in damage to
equipment, or cause injury or death.
• If the compressed air system of the vehicle being towed has
emergency air and service air lines, they must not be connected.
CAUTION
• Do not use towing as a means to start engine of vehicle with
automatic transmission. Refer to disabled vehicle operator’s
manual for towing instruction. Failure to so may will result
in damage to vehicle.
• Maximum towing speed shall not exceed 35 mph (56 km/h) on
paved highway or 15 mph (24 km/h) on off-highway surfaces.
NOTE
When towing M939/A1/A2 series vehicles with inoperative
compressed air system, the spring brakes must be caged.
(1) Position rear of wrecker directly in front of disabled vehicle.
(2) If tires, transmission, and steering of disabled vehicles are serviceable,
proceed to step 4 and install towbar (10) to front bumper shackle brackets (14).
(3) If disabled vehicle has no shackle brackets (14), or if tires, transmission,
and/or steering of disabled vehicle are unserviceable, proceed to step 5d and use lifttow
procedure.
(4) To tow a disabled vehicle using front bumper shackle brackets:
(a) Remove lifting shackles (13) from bumper (15) of disabled vehicle.
(b) Install clevis (12) end of towbar (10) on front bumper shackle
brackets (14) and secure in place with clevis bolt (16) and safety pin (11).
(c) Install yoke (1
![Cool 8) 8)](https://www.steelsoldiers.com/images/smilies/icon_cool.gif)
end of towbar (10) to wrecker pintle hook (19).
.WARNING.
Crisscross and connect utility chains between vehicles in the
event towbar breaks or becomes disconnected. Failure to do this
will result in injury or death.
(d) Crisscross and connect
utility chains (17) to spring hangers (20)
on towed vehicle and secure to towing
vehicle.
(e) Connect emergency and
service air line (22) to respective half
coupling (21) on each vehicle.
(f) Release parking brake
and place transmission, transfer case,
and PTO of disabled M939/A1/A2 series
vehicles in neutral.
(g) Reverse steps a through f
after completion of towing.
5) For lift-tow operations:
(a) Attach whiffletree (3) to lifting shackles (4) of disabled vehicle.
Whiffletree (3) is attached the same way as a towbar (12). Refer to step 4c.
(b) Lower crane block (2) and insert hook (5) through center hole of
whiffletree (3). Refer to crane operation (para. 2-24d).
(c) Remove two retaining pins (11) and towbar adjustment pins (10).
Slide out leg extensions (9).
(d) Attach two clamps (
![Cool 8) 8)](https://www.steelsoldiers.com/images/smilies/icon_cool.gif)
to clevis (13) of leg extensions (9) and secure
in place with clevis bolts (14) and attached safety pins (15).
(e) Loosen two tension adjusting nuts (7) on clamps (
![Cool 8) 8)](https://www.steelsoldiers.com/images/smilies/icon_cool.gif)
.
(f) Position clamps (
![Cool 8) 8)](https://www.steelsoldiers.com/images/smilies/icon_cool.gif)
against front axle (16) of disabled vehicle and
wrap clamp chain (6) around axle and back up through clamp (
![Cool 8) 8)](https://www.steelsoldiers.com/images/smilies/icon_cool.gif)
. Lock in place by
turning tension adjusting nut (7) until secure.
(g) Repeat step f with second clamp (
![Cool 8) 8)](https://www.steelsoldiers.com/images/smilies/icon_cool.gif)
in position against axle (16) on
opposite side of forward axle.
NOTE
If necessary, adjust length of towbar while performing step h.
Yoke end of towbar should extend one foot or more beyond front
bumper of disabled vehicle.
(h) After both clamps (
![Cool 8) 8)](https://www.steelsoldiers.com/images/smilies/icon_cool.gif)
are secured to disabled vehicle, slide leg
extensions (9) back into towbar (12) and secure in place with adjustment pins (10)
and retaining pins (11).
(i) Install yoke end of towbar (12) on wrecker pintle hook (16).
(j) Disengage brakes and remove propeller shafts between
transmission and transfer and place transfer in high range of disabled M939/A1/A2.
(k) Raise crane block (2) and lift front wheels of disabled vehicle off
ground until towbar is level (parallel to ground).
(l) To secure from lift-tow operation, reverse steps a through k.