Tuff Country 14731 - GM 88-91 1/2 ton Blazer / Sub 4 box kit (systems with rear springs) User Manual
Page 4
 
on the passenger side. 
 
9. 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 the front 
eyelet bushings and sleeves a side for later re-
installation. The rear eyelet bushings and sleeves may 
be discarded. 
 
10. Locate the new polyurethane lube packs, (4) 
MO2360 spring eye bushings and (2) S10006 spring eye 
sleeves. Spread the new polyurethane over the new 
bushings 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. 
 
11. 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
12. 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. 
 
13. 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
14. 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 
using the new U-bolt high nuts and washers. Torque to 
130 ft lbs. 
See Illustration # 5
15. 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 # 4. Special Note: If you are installing a 2” or 3” 
suspension system, you may skip this step. 
16. Carefully remove both hydraulic floor jacks from 
under the front differential. 
 
17. 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. 
 
18. 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 # 17. Repeat procedure 
on the passenger side. 
See Illustration # 6
 
19. 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 
recommends using a 20” fully extended nitrogen gas 
shock when installing a 2” suspension system and a 
23” fully extended nitrogen gas shock when 
installing a 3” or 4” suspension system. If the 
vehicle that you are working on has the dual shock 
option, Tuff Country recommends using a 23” fully 
extended cellular gas shock for the auxiliary shock 
when installing a 2” suspension system and a 26” 
fully extended cellular gas shock for the auxiliary 
shock when installing a 3” or 4” suspension system. 
Repeat procedure on passenger side.
See Illustration # 6
 
20. Install the tires and wheels and carefully lower the 
vehicle to the ground. 
 
21. 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
22. 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. 
 
23. 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