Wilwood W4A Big Brake Rear Brake Kit For OE Parking Brake - Manual (Page 4)

Modifications
• The rear backing plate/dust shield and OE caliper mounting tabs needs to be modified as shown in Figure 3 to clear the new Wilwood
rotor and caliper mounting bracket (1). NOTE: It is recommended that the backing plate be removed before modification, and the
modifications be performed by a qualified machine shop. After backing plate removal, cut the dust shield to 8.75” diameter as shown
in Figure 3. Temporarily mount the caliper mounting bracket as shown in Figure 3 and Photo 1. Figure 3, Item “A”: Examine the fit of
the bracket against the OE caliper mounting tabs and remove just enough material so that the bracket mounts flush. Figure 3, Item
“B”: Once the bracket fits flush, mark the tabs to match the bracket profile as shown. Remove the bracket, then remove just enough
material from the OE mount ears to match the marks.
Assembly Instructions (numbers in parenthesis refer to the
parts list and Figure 1 on the preceding pages):
• The caliper mount bracket (1) should initially be installed with
clean, dry threads on the mounting bolts. Orient the bracket as
shown in Figure 1 and install using the saved OEM caliper mount
bolts. Initially place one .033” thick shim (2), on each bolt
between the bracket and upright, Figure 1 and Photo 1.
Temporarily tighten the mounting bolts. NOTE: The bracket
must fit squarely against the mount bosses on the upright.
Inspect for interference from casting irregularities, machining
ridges, burrs, etc. Later, after the caliper alignment has been
checked, the mount bolts will be secured using red Loctite
® 271.
• Orient the rotor (3) and the hat (4) as shown in Figure 1 and
Photo 2. Attach rotor to hat using bolts (6) and washers (5).
Using an alternating sequence, apply red Loctite® 271 to the
threads and torque bolts to 140 in-lb. For an added measure of
security, the bolts may be safety wired using standard 0.032 inch
diameter stainless steel safety wire as shown in Figure 4.
Please refer to Wilwood’s data sheet DS-386 (available at
www.wilwood.com/Pdf/DataSheets/ds386.pdf ) for complete
safety wire installation instructions.
• Slide the hat/rotor assembly onto the axle hub taking care to
align the small countersunk hole in the hat (4) with the small
threaded hole in the hub, Figure 1. NOTE: The hat must fit flush
against the axle hub flange or excessive rotor run out may result.
Install three lug nuts (finger tight) to keep the hat/rotor assembly
in place while continuing with the installation.
Modifications and Assembly Instructions
CUT DUST SHIELD
DOWN TO 8.75 (222,3)
DIAMETER
WILWOOD BRACKET
P/N 250-11308
TRIM UPRIGHT TO
MATCH WILWOOD
BRACKET
CHECK FOR
INTERFERENCE
HERE. REMOVE
MINIMAL MATERIAL
FROM UPRIGHT
TO CLEAR
BRACKET. A
B
Figure 3. Backing Plate / Dust Shield / Caliper Mounting Tabs Modifications
Page 4
Photo 1 Photo 2
BEGIN BY SLIDING THE 0.032"
DIAMETER WIRE THROUGH TWO OF
THE HOLES (LEFT) THAT ARE 180°
APART. TWIST THE WIRE AS
SHOWN (BELOW) USING SAFETY
WIRE PLIERS. NOW SLIDE ONE
WIRE THROUGH TWO OF THE
HOLES (180° APART) AND WRAP THE
OTHER WIRE AROUND THE BOLT.
TWIST THE WIRES TOGETHER TO
FORM A PIGTAIL. SEE DS-386 FOR
COMPLETE DETAILS.
Figure 4. Safety Wire Diagram Photo 3