Trail Master Suspension TM104N CHEVEROLET/GMC 1/2 TON 4WD SUSPENSION LIFT KIT - Manual (Page 17)

17
TM104N
Revised
1.27.14
Prepare to Install Rear Suspension
1. Raise the rear of the truck enough for the tires to clear the ground and use jack stands on the frame to support
the truck. Remove the rear tires and wheels.
2. Carefully remove the OEM shock absorbers. It may be necessary to raise the differential housing slightly to
facilitate their removal.
3. Remove the factory bump stops from the vehicle.
4. One side at a time, support the differential housing on the side being modified. Remove the “U” bolts from that
axle end and discard. Carefully lower the differential away from the OEM springs. Remove and discard the
OEM riser block from its mount pad. Take careful note of the position of the factory spring packs.
Install Rear Suspension
1. ADD-A-LEAF (13125-1) INSTALLATION NOTE: In order to properly install the add-a-leaf spring, it will be
necessary to contain the elasticity in the leaf spring with “C” clamps when the center bolt is removed.
Some springs have a factory helper spring consisting of one or more flat leaves installed at the bottom
of the leaf pack. DO NOT install the add-a-leaf spring in or below the helper spring.
2. Hold the spring assembly securely together with “C” clamp. If necessary remove any spring leaf alignment
clamps. Remove the spring center bolt. A hammer and drift punch may be used to drive it out if necessary.
3. Carefully remove “C” clamps and lay unassembled leaves aside.
NOTE: Add-a-leaf will be placed in the spring assembly progressively according to length. For
example, if the existing leaves are 32” long and 25” long and the add-a-leaf is 28” long, place the add-a-
leaf between the existing leaves.
4. Apply a small amount of grease to the end of the add-a-leaf, place it in the spring assembly as described in the
note above, and reassemble the leaf springs using the “C” clamps also insert the new center bolt (PN 97-380)
and torque the center bolt nut to 20 ft./lbs. With a hacksaw, cut the center bolt even with the top of the nut.
5. Loosely assemble the complete spring assemblies into their respective axle mounts. As shown in
ILLUSTRATION 19, place the (PN 95-401) blocks in position. Make sure the pin in the block is in the hole of the
axle housing spring pad. The short end of the block goes toward the front of the vehicle. Install the block so the
pinion moves up.
6. If you are installing an optional traction bar kit, install the riser block as is. If you are not using the traction bars, it
will be necessary to grind off approximately 1/4” of the locating dowel. Make sure after grinding that you test fit
the riser block to ensure it fits the axle housing without interfering with the axle tube. Install the new 4” riser
block, short end to the front, to the mount pad on the axle housing and raise the axle housing until the riser block
hole fits around the new leaf spring center bolt.
7. Install the new “U” bolts over the leaf spring assembly and using the new washers and nuts supplied along with
the existing spring plates, torque the U-bolt nuts to 105 ft./lbs. See Illustration 19.
8. Install the bump stop extensions provided (PN 82-2144). See Illustration 17.
9. Repeat these steps on the other side of the vehicle.
10. Before installing your new Trailmaster shock absorbers (PN 75870W), it is necessary that you check for
adequate clearance. Temporarily install your Trailmaster shocks into the shock mounts. Carefully check for
clearance issues. If there are areas that come in contact with or are very close to your new shocks, carefully
remove sufficient material to ensure trouble free operation. Pay particular attention to the area around the lower
shock mount. When all clearance issues have been resolved, install your new Trailmaster shock absorbers and
recheck all fasteners for proper installation and torque. See Illustration 18.
11. Install your wheels and tires and lower the vehicle to the ground.
12. After installation is complete, double check that all nuts and bolts are tight. Refer to the chart at the end of this
document for torque specifications. (Do not retighten nuts and bolts where thread locking compound was used).