Tuff Country 16721 - GM 73-87 6 3/4 ton box kit (systems with rear springs) - Manual (Page 4)

using the new U-bolt high nuts and washers. Torque to
130 ft lbs.
See Illustration # 5
16. Working on the driver side, re-install the stock drag
link back into the stock steering arm. Secure using the
stock caster nut and cotter pin that was removed from
step # 5.
17. Carefully remove both hydraulic floor jacks from
under the front differential.
18. Locate (2) larger brake line relocation brackets, (2)
5/16” x 1” bolts, (4) 5/16” flat washers and (2) 5/16”
unitorque nuts. Working on the driver side, secure the
new brake line extending bracket to the stock location
and secure using the new 5/16” x 1” bolt and hardware.
Torque to 18 ft lbs. Make sure to use thread locker or
locktite on these bolts. Repeat procedure on the
passenger side.
19. Working on the driver side, move the stock hard
brake line located in the inner part of the frame rail under
the stock frame. Reconnect the hard line and the soft line
back together around the new brake line extending
bracket that was installed in step # 18. Repeat procedure
on the passenger side.
See Illustration # 6
20. Working on the driver side, install the new front
shocks absorbers using the stock hardware removed
from step # 2 . Special Note: Shocks are not included
with this suspension system, shocks need to be
ordered as a separate part number, Tuff Country EZ-
Suspension recommends using a 23” fully extended
nitrogen gas shocks. If the vehicle that you are
working on has the dual shock option, Tuff Country
EZ-Ride Suspension recommends using a 26” fully
extended cellular gas shock for the auxiliary shock.
Repeat procedure on passenger side.
See Illustration # 6
21. Locate (2) front sway bar drop tubes, (4) 7/16” x 2
1/2” bolts, (4) 7/16” flat washers and (2) 7/16” unitorque
nuts. Working on the driver side, install the new sway bar
drop tube between the stock sway bar and the stock
sway bar mounting point. Secure using the new 7/16” x 2
1/2” bolts and hardware. Torque to 35 ft lbs. Special
Note: The front sway bar drop tubes are the tubes
that measure 1” tall. Special Note: If the vehicle that
you are working on does not have a stock front sway
bar, please discard this step. Repeat procedure on the
passenger side.
See Illustration # 7
22. Install the tires and wheels and carefully lower the
vehicle to the ground.
23. With the weight of the vehicle on the ground, torque
the top and bottom spring eye shackle bolts on the driver
and passenger side to 40 ft lbs.
Front End Installation Complete
Rear End Installation
24. To begin installation, block the front tires of the
vehicle so that the vehicle is stable and can’t roll forward.
Safely lift the rear of the vehicle and support the frame
with a pair of jack stands. Place a jack stand on both the
driver and passenger side. Next remove the wheels and
tires from both sides.
25. Locate (1) rear brake line extending bracket, (1)
5/16” x 1” bolt, (2) 5/16” flat washers, (1) 5/16” unitorque
nut and (1) 5/16” lock washer. Remove the stock brake
line bracket from the rear differential and save stock bolt
for later re-installation. Secure the new brake line bracket
to the rear differential housing using the stock bolt.
Special Note: Make sure to use thread locker or lock
tite. Next, attach the stock brake line bracket to the
newly installed brake line bracket and secure using the
new 5/16” x 1” bolt and hardware. Torque to 16 ft. lbs.
See Illustration # 8
26. Position a pair of hydraulic floor jacks under the rear
axle. Place one jack stand on the driver side and one on
the passenger side. Raise up on both hydraulic floor
jacks at the same time until they make contact with the
rear axle.
27. Working on the driver side, remove the stock shock
and save the stock hardware for later re-installation.
Special Note: New longer rear shocks are needed, if
you have not already ordered shocks, please contact
Tuff Country or your local Tuff Country dealer and
order the proper shocks. Tuff Country recommends
using a 30” fully extended nitrogen gas shock when
installing a 6” suspension system. Repeat procedure
on the passenger side.
28. Working on the driver side, remove the (2) stock rear
U-bolts and discard. Set the upper U-bolt plate a side for
later re-installation. Repeat procedure on passenger side
29. Lower down on both hydraulic floor jacks at the same
time until the stock springs separate from the stock rear
axle. Lower down approximately 7”. Special Note: Make
sure not to over extended any brake lines or hoses
when lowering the axle. This will allow you enough
room for the new rear springs to be installed.
30. Working on the driver side. Remove the stock spring
from the stock location. The stock spring and stock
spring eye hardware may be discarded. Repeat
procedure on the passenger side.
31. Locate the new rear springs and the new rear spring
eye hardware. Working on the driver side, install the new
rear spring into the stock location and secure using the