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

Front End Installation:
1. To begin installation, block the rear tires of the vehicle
so that the vehicle is stable and can’t roll backwards.
Safely lift the front of the vehicle and support the frame
with jack stands. Place a jack stand on both the driver
and passenger side. Next remove the wheels and tires
from both sides.
2. Working on the driver side, remove the stock shock
from the stock upper and lower mounting point and save
hardware for later re-installation. The stock shocks may
be discarded. Special Note: New longer front 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 23” fully extended
nitrogen gas shock. Repeat procedure on the
passenger side. Special Note: If the vehicle that you
are working on has the dual shock option, remove
both shocks and discard.
3. Working on the driver side, disconnect the stock brake
line at the frame mount. Let the stock brake line hang.
Special Note: Brake fluid is going to leak out, it is a
good idea to place a bucket under the vehicle to
catch the brake fluid that will leak out. After the
installation is complete, the brake lines will need to
be bleed. Repeat procedure on the passenger side.
See Illustration # 1
4. Working on the driver side of the vehicle, remove the
stock sway bar from the stock frame mount. The stock
hardware may be discarded. Let the stock sway bar
hang. 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.
5. Working on the driver side, remove the stock cotter pin
and caster nut that connects the stock drag link ball joint
to the stock steering arm. If you are not going to replace
the stock steering arm with a raised steering arm, save
the stock cotter pin and caster nut for later re-installation.
Remove the stock drag link from the stock steering arm
and let the stock drag link hang. Special Note: Tuff
Country EZ-Ride Suspension highly recommends
installing a raised steering arm once a 6”
suspension system has been installed. If you have
not already ordered your raised steering, please
contact Tuff Country or your local Tuff Country
dealer and order part # 70100.
6. Place a pair of hydraulic floor jacks under the front
axle. Place one hydraulic floor jack on the driver side and
one on the passenger side.
7. Working on the driver side, remove the stock U-bolts
from the stock location. The stock U-bolts and hardware
may be discarded. Repeat procedure on the passenger
side.
8. Carefully lower down on both hydraulic floor jacks at
the same time approximately 6”. This will allow enough
room for the new front springs to be installed into the
stock location.
9. Working on the driver side, remove the stock spring
from the stock location. The stock front spring, stock
front spring hanger hardware and stock front spring
shackle hardware may be discarded. Repeat procedure
on the passenger side.
10. Locate the new front leaf springs. Working on the
front and rear eyelet’s of the front springs, remove the
new sleeves and bushings from each end and set a side
for later re-installation.
11. Locate the new polyurethane lube packs. Spread the
new polyurethane over the new bushings that were
removed from step # 10 and re-install them back into the
new front spring assembly. Make sure to re-install the
new sleeves. Special Note: Make sure to use the new
polyurethane lube packs prior to inserting the new
bushings back into the new front springs. This will
increase the life of the bushing, prevent squeaking
and help with ride quality.
12. Locate the new front spring eye hardware. Working
on the driver side, install the new front spring into the
stock location and secure using the new spring eye
hardware. Make sure to use thread locker or locktite
on these bolts. Torque the front spring eye hanger
hardware to 120 ft lbs. Special Note: Do not torque
the front spring eye shackle hardware at this time.
Once the vehicle is lowered to the ground, the front
spring eye shackle will be torque to 40 ft lbs. Repeat
procedure on the passenger side.
See Illustration # 2 / Front Spring Hanger
See Illustration # 3 / Front Spring Shackle
13. Carefully raise up on both hydraulic floor jacks at the
same time until the newly installed front springs seat
properly to the stock front spring perches.
14. Locate (2) new 5/8” x 3” x 7 5/8” Round U-bolts, (4)
5/8” U-bolt High Nuts and (4) 5/8” U-bolt Washers.
Working on the driver side, install the new U-bolts into
the stock location and secure using the new U-bolt high
nuts and washers. Torque to 130 ft lbs.
See Illustration # 4
15. Locate (1) new 5/8” x 3” x 7 5/8” Round U-bolt, (1)
new 5/8” x 3 1/2” x 9 5/8” Round U-bolt, (4) 5/8” U-bolt
High Nuts and (4) 5/8” U-bolt Washers. Working on the
passenger side, install the new 5/8” x 3 1/2” x 9 5/8”
round U-bolt into the stock location around the stock
front differential inside location. Secure using the new U-
bolt high nuts and washers. Secure the new 5/8” x 3” x 7
5/8” round U-bolt into the stock outside location. Secure