Drum Brake Description
Important:
• Inspect all of the new components included in the repair kit used
in order to service the drum brakes. • Lubricate the parts as specified. • Do not use lubricated compressed air on the brake parts. Damage
to the rubber components may result. • If any hydraulic component is removed or disconnected, bleed all
or part of the brake system. • Replace the brake shoes in sets only. • The torque values specified are for dry, non-lubricated fasteners. • Perform service operations on a clean bench, free from mineral
oil materials.
This drum brake has a leading/trailing design. The drum brake exhibited the following characteristics:
| • | Equivalent performance to other drum brakes |
| • | Improved performance reliability over other drum brakes |
A single universal spring holds both shoe and lining assemblies to the backing plate and also act as a retractor spring for them. When the brakes are applied, the wheel cylinder moves both shoes put in order to contact the drum. With forward wheel rotation, the forward (leading) brake shoe wraps into the drum and self-energizes. Force from the shoes is transferred through the fixed anchor and backing plate to the axle flange. The drum brakes self-adjust during any brake application, with no vehicle motion required. Once the shoes are installed, do not switch positions, even though the forward shoe normally wears faster than the rear shoe. Switching positions may render the self-adjustment inoperative and result in increased pedal travel. For diagnosis of this system, refer to Hydraulic Brake Diagnostic System Check in Hydraulic Brakes.
