Tuff Country 13720 - GM 73-87 3/4 ton 3 box kit - Manual (Page 4)

Rear End Installation
20. 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.
21. 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 1/4” bolt and hardware. Torque to 16 ft.
lbs.
See Illustration # 7
22. 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.
23. Working on the driver side, remove the stock shock
and save the stock hardware for later re-installation.
Longer shocks are needed, so the stock shocks may be
discarded. Repeat procedure on passenger side.
24. 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
25. Lower down on both hydraulic floor jacks at the same
time until the stock springs separate from the stock rear
axle. Lower down approximately 4”. 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 blocks to be installed.
26 Locate (2) new 3” lifted rear blocks. Working on the
driver side, install (1) new 3” lifted block between the
stock rear axle and the stock spring assembly. Special
Note: The new 3” lifted block has a slight taper to it,
the small end of the new block needs to be installed
with the small end towards the front of the vehicle.
Repeat procedure on passenger side.
See Illustration # 8
27. Raise up on both hydraulic floor jacks at the same
time until the driver and passenger side stock spring
assembly seats flush with newly installed 3” block.
28. Locate (4) new 5/8” x 3 1/2” x 12 1/2” Round U-bolts,
(8) 5/8” U-bolt high nuts, (8) 5/8” U-bolt washers and the
stock upper U-bolt plates that were removed from step
# 24. Working on the driver side, install (2) new 5/8” x 3
1/2” x 12 1/2” round U-bolts into the stock location and
secure using the new 5/8” high nuts and washers.
Torque to 130 ft lbs. Repeat procedure on passenger
side. Special Note: With a suitable cutting tool, cut
off the excess U-bolt threads on all (4) rear U-bolts.
See Illustration # 8
29. Working on the driver side, install the new rear
shocks absorbers using the stock hardware removed
from step # 23. Special Note: Shocks are not included
with this suspension system, shocks need to be
ordered as a separate part number, Tuff Country EZ-
Ride Suspension recommends using a 26” fully
extended nitrogen gas shocks. Repeat procedure on
passenger side.
See Illustration # 8
30. Check and double check to make sure that all step
related with the front and rear end were performed
properly. Check and double check to make sure that all
stock and new hardware is torque to proper torque
specifications. Use the torque sheet at the beginning of
the installation manual.
31. Install the tires and wheels and safely lower the
vehicle to the ground.
32. Once the installation is complete, make sure to bleed
the brake lines. Also, using the proper brake fluid, make
sure to top off the brake fluid level.
CONGRATULATIONS INSTALLATION COMPLETE
Special Note: After the completion of the installation,
Tuff Country EZ-Ride Suspension recommends
taking the vehicle to an alignment shop and having a
proper front end alignment performed.
It is also a good idea to keep a close watch on the
front and rear drive line U-joints. If they start to wear
out, make sure to replace them.
If you have any questions or concerns, please feel
free to contact Tuff Country or your local Tuff
Country dealer.