Bendix Commercial Vehicle Systems DOUBLE ANCHOR PIN CAM BRAKE 5/04 - Manual (Page 7)

7
FIGURE 10
USE RIVETS OF CORRECT LENGTH AS SHOWN
CORRECT TOO LONG
TOO SHORT
CAUTION: The lip of the grease seals must be installed
correctly to prevent possible damage. The lip of the
seal that is installed in the spider must enter the opening
first. The lip of the seal that is installed in the opposite
end of the cam tube must enter last. (See Figure 9).
4. Install a new actuator bracket seal ring between the
spider and cam tube of the bracket. Install the actuator
bracket and cam tube onto the spider using four cap
screws and lockwashers. Torque to 70-80 ft. lbs. Secure
the actuator to the bracket using the two nuts and
washers. Torque to vehicle manufacturer’s specification.
5. If removed, reinstall the dust shields. Tighten the six
cap screws and lockwashers to 90-110 in. lbs. torque.
6. Place the cam head flat washer over the splined end of
the cam shaft and slide it to the opposite end, next to
the head of the cam. Install washer so that the bent
ends face away from the head. Coat cam shaft journals
with light film of chassis lube. Do not coat “S”-cam head.
7. Install the cam shaft with cam head flat washer into the
cam tube. Be careful not to damage the grease seals.
8. Install the thick cam shaft flat washer, the slack adjuster,
spacers, washer, and a new snap ring in that sequence
onto the splined end of the cam shaft. Adjust end play of
the cam shaft to between .005" and .045" by using the
appropriate number of spacer washers. Make sure the
snap ring is seated into the groove at the end of the
splined camshaft.
9. Install the two anchor pins into the anchor pin bushings.
Center the anchor pins in the bushings so they protrude
equally from each end of the bushings.
10. Install new brake shoe retaining springs. Engage hook
ends of the two springs into each of the holes of the two
brake shoes.
11. Place the top shoe onto the spider by engaging the open
slots on the end with the retaining springs onto the anchor
pin. Place opposite end of the shoe against the S-cam.
Swing the opposite shoe with springs attached back
until slots in the shoe engage the other anchor pin, then
swing shoe towards the S-cam. Spring tension will hold
the shoes in this position. NOTE: When placing slots of
the shoes onto the anchor pins, be sure to match the
flat surfaces of the mating parts.
12. Place the short hook of the brake shoe return spring
onto the top return spring pin. Be sure spring is installed
so that the long hook on the other end of the spring is
facing the web of the brake shoe. Hold shoes against
the S-cam and push the long hook of the brake shoe
return spring over the opposite return spring pin until it
snaps in place.
13. Insert a sturdy bar between the end of one of the brake
shoes and the spider housing at the S-cam end of the
shoe. Pry down until the brake shoe roller and pin can
be installed between the S-cam and the slots in the end
of the brake shoe. Repeat the same procedure on the
other shoe.
14. Adjust the slack adjuster until the yoke pin can be
installed through the proper hole in the arm. Install a
new cotter pin to retain. Make sure the cam rollers are
in the lowest position on the cam.
15. Lubricate the cam shaft bushings by filling the cam shaft
tube with chassis lube through the zerk fitting provided.
Fill until grease is forced out in the area of the slack
adjuster. Grease should not appear at the cam head
end. If it does, the seal has not been properly installed,
or the old seals should be replaced.
16. Reinstall brake drums and wheels. Torque and adjust to
manufacturer’s specifications.
17. Spin the wheel slowly and adjust the slack adjuster until
wheel will no longer turn. Back off slack adjuster just
enough for wheel to spin freely. Be sure to adjust brakes
equally on each axle.
18. Apply and release brakes and observe slack adjusters.
Both slacks on each axle should respond rapidly and in
unison during application and release.
19. Drive vehicle at a low speed in a safe area and check for
brake effectiveness prior to putting back into service.
RELINE PROCEDURE
When removing rivets from the brake shoes, be careful to
avoid doing any damage to the holes in the shoe. Do not
use a chisel to shear them off as the force will elongate the
rivet holes. Neglecting any elongated holes may result in a
loose lining installation. If holes are burred, they should be
filed down flush with the shoe table.
Rust often develops on the surface of the shoe table under
the brake lining or blocks. In addition, scale may form from
salt on the highways, or tar and oil may find their way into
the brake assembly. During every reline job, shoe tables
should be thoroughly cleaned. The best procedure is to steam
clean the entire shoe or put it in a degreaser.
After cleaning the shoe, the shoe table should be scraped
clean of rust and scale. Any burrs or nicks should be filed
smooth. At the same time, the entire shoe should be
examined to see whether it is worn or bent.
The shoe should be either reconditioned or discarded. It is
also necessary to check for flat spots on the shoe that can
be caused by cleaning away the rust from the area that was
under the block previously. This can cause a mismatch of
shoe and lining arcs. After the shoe is cleaned and inspected,
it should be given a coating of rust preventative paint. Such
treatment of a new, unpainted shoe is also suggested to