Wilwood W4A - Manual

4700 Calle Bolero • Camarillo, CA 93012 • www.wilwood.com • Sales: (805) 388-1188 • E-mail Tech Assistance: [email protected]
189 REV DATE: 03-26-12
W4A RADIAL MOUNT CALIPER
Caliper Highlights:
W4A forged four piston calipers comfortably
deliver heavy duty stopping power for the road,
track, or back country trail. It incorporates
purebred race technology into a body design
with widespread adaptability. The W4A is a
modified version of the W6A. It provides two
additional options for matching piston bore
volumes with master cylinder output and rear
caliper size for correct bias proportioning. It is
also the excellent choice for many racing
categories that may not permit six piston calipers.
Radial mounting, two options for piston volume, and
a rotor diameter range from 12.19" to 14.25" give this
caliper the versatility necessary to suit all types of heavy
weight brake requirements.
The W4A body is the product of FEA computer design and stress flow forging technology. FEA technology allows the
designer to test the prototype model in a computer environment to determine the optimal structural design within the
dimensional parameters of the component. Stress flow forging produces a part with the internal grain structure of the
metal aligned in the direction of the flow of the body contour. The results are a caliper with superior clamping efficiency
and ultimate strength against fatigue, stresses, and distortion under load.
The W4A generates big brake clamping force with four differential bore stainless steel pistons. Stainless steel is used
for its high resistance to corrosion and low thermal conductivity that reduces the heat transfer from the pads. The
differential bore pattern balances pad loading against mechanical influences and changes in temperature over the
length of the pad to help maintain even pad wear. High temperature bore seals provide long service life in hard braking
environments and maintain their resilience to provide positive piston retraction on release.
The performance and durability of the W4A is further enhanced with SRS bridge plates, snap-ring locked pad retainer
pins, recessed two-piece bleed screw assemblies and dampen mounted fluid transfer tubes. SRS bridge plates
eliminate all bridge wear caused by pad gouging to extend the service life of the caliper. The spring-loaded action of
the plates also eliminates pad rattle and other harsh noise by damping the engagement harmonics that can contribute
to pad squeal. Snap ring clips lock the pad pins in place to provide positive retention and allow easy service access
without caliper removal. The two-piece bleed screws protect the caliper body from damage that can occur from over
tightening the screw. The bleeds are also recess mounted for protection against impact and debris. They are easily
replaced should they become worn. The fluid tubes are dampen mounted to protect them from fatigue or damage from
vibration or debris. Finally, the calipers are anodized in high luster black to protect them from corrosion and maintain
their high-tech appearance inside the wheel. The W4A is also available with a gloss red finish and other custom
Wilwood colors by order.
ORDERING INFORMATION:
REAR MOUNT PART NUMBER
BORE SIZE DISC WIDTH RH LH
1.88 / 1.62” 47,8 / 41,1 mm 1.25” 31,8 mm 120-9679-RS (1) 120-9680-RS (1)
1.62 / 1.38” 41,1 / 35,1 mm 1.25” 31,8 mm 120-9681-RS (1) 120-9682-RS (1)
PART NUMBER
BORE SIZE DISC WIDTH RH LH
1.25 / 1.25” 31,8 / 31,8 mm 1.10” 27,9 mm 120-10904-R (2) 120-10904-L (2)
NOTES: (1) AVAILABLE RED, ADD “R” TO END OF PART NUMBER WHEN ORDERING. FOR OTHER CUSTOM WILWOOD COLORS, CONTACT
THE FACTORY.
(2) AVAILABLE RED, ADD “RD” TO END OF PART NUMBER WHEN ORDERING