16
Section 2
Hydraulic Brakes
Adjust H Brake
NOTE: Each brake shoe must be adjusted
separately.
NOTE: If adjustable anchor pins are not used,
omit Brake Adjustment Steps 2 and 3.
The first adjustment after assembly must be
carefully made to put the shoes in the correct
position in the brake drum.
1. Turn the eccentric cam adjustment so that the
lining touches the brake drum. Figure 2.18.
2. Turn the anchor pin adjustment, if used, until
the brake drum just rotates freely. Figure 2.18.
3. Repeat Steps one and two until additional
rotation of the anchor pin no longer decreases
the brake drum resistance.
4. Tighten the anchor pin lock nut to the torque
shown below:
•
0.750-16 Thread Size:
Tighten to 85-115 lb-ft (115-156 N•m)
when using a 13X-13 jam nut.
Tighten to 100-145 lb-ft (136-197 N•m)
when using a standard height nut.
•
0.875-14 Thread Size:
Tighten to 150-190 lb-ft (203-258 N•m).
•
0.875-11 Thread Size:
Tighten to 180-230 lb-ft (244-312 N•m).
5. Turn the adjusting cam in the opposite
direction until the brake can rotate freely.
6. Use the same procedure (Steps 1 - 5) to adjust
the other shoe.
7. Further adjustment for lining wear must be
made with the adjustment cams only. Adjust
the lining until a slight resistance can be felt
when the brake drum is rotated.
8. Turn the cams in the opposite direction until
the brake drum just can rotate freely.
Wheel Cylinder
Maintenance
WARNING
•
These hydraulic brakes are all internal wheel
cylinder brakes. If master cylinders and/or
power units are being serviced, it is required
that they be able to maintain 12-20 PSI (0.8-1.3
bar) residual line pressure. Otherwise these
internal wheel cylinder brakes will not
perform properly and can cause serious
personal injury.
•
Leaks that coat the outside of the boot and
cylinder with fluid can cause a decreased fluid
level in the reservoir or dampen and stain the
brake linings. Any leaks must be immediately
corrected. Contaminated linings must be
replaced to prevent serious personal injury.
•
Some hydraulic brake systems use a
non-petroleum hydraulic brake fluid (SAE-J-
1703 or SAE-J-1702f) some systems use
petroleum base brake fluids. Make sure that
you use the correct brake fluid and seals as
required in the vehicle brake system
specifications. Do not mix different types of
brake fluid. The use of the wrong brake fluid
can damage the cup seals of the wheel
cylinder, cause loss of braking and serious
personal injury.
Check to determine if wheel cylinders need over-
hauling or replacing:
•
when you replace the brake shoes and
•
when a cylinder leaks.
