| Malfunction (Symptoms) |
Probable Causes |
Corrective Actions (Remedies) |
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| Wear Braking |
Brakes out of adjustment |
Adjust brakes |
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Low Brake Fluid |
Correct any leaks; then fill master cylinder |
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Low hydrovace vacuum |
Check engine vacuum. Check vacuum lines and tighten clamps to correct leaks. |
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Sticking brake shoe |
Lubricate shoe contact points on backup plate with lubricant |
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Excessively worn lining |
Replace lining |
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Malfunctioning hydrovac |
Check air filter for clogging. Check connections; tighten as necessary. Replace defective unit. |
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Obstructed hydraulic brake line |
Clean with compressed air or replace line. Relieve any constricting pressure. Bleed system following cleaning or replacement of lines. |
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| Erratic braking |
Brakes out of adjustment |
Adjust brakes |
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Lubricant on brake fluid on lining |
Correct any leaks. |
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"Brake drum has hard spots or is deformed" |
Replace drum |
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Loose or defective wheel bearing |
"Clean pack tighten or replace bearing." |
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Shoe web-to-hold down washer gap not set to 0.015 inch |
Check and reset as required. |
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| Brakes chatter or squeak |
Loose backup plate mounting bolts |
Tighten loose bolts. Torque front to 86 - 94 ft-lbs. Rear 54 - 59 ft-lbs |
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"Dirt dust or other foreign matter in brake" |
"Clean drum backup plate and shoes with compressed air" |
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Distorted or damaged brake drum or shoe |
Tighten or replace defective part. |
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Loose lining or incorrectly ground drum |
Replace lining; or cam-grind drum. |
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| Brakes fail to release |
Brakes out of adjustment |
Adjust brakes |
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Brake pedal lever sticking pedal return spring weak |
"Lubricate pedal lever clevis pin replace spring" |
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Broken brake shoe return spring |
Replace spring. |
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Distorted brake shoe |
Replace shoe |
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Obstructed brake line |
Clean or replace defective line. Relieve any constricting pressure. |
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Distorted or swollen cup(s) in wheel cylinder or master cylinder |
Replace defective cylinder |
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Loose or defective wheel bearing |
"Clean pack or replace bearing" |
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Loose backup plate mounting bolt(s) |
Tighten loose bolt(s) (torque front to 86 - 94 ft-lbs. Rear to 54 - 59 ft-lbs) |
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Hydrovac not releasing pressure |
Check air filter for clogging and air line for constriction. Correct any faults and check. Replace defective unit. |
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| Braking fades |
Brakes out of adjustment |
Adjust brakes |
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Lining saturated with fluids |
"Correct any leaks then replace lining." |
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Brake drum too thin |
Replace |
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Brake fluid condition deteriorated (low boiling temperature) |
Drain and flush hydraulic system then fill and bleed system. |
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Hydrovac leaks |
Check and correct leaks; or replace leaking unit. Tighten loose connections |
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| Low pedal |
Low fluid level |
Check and correct leaks; fill master cylinder |
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| "Soft" pedal operation |
Air in hydraulic system |
Bleed system |
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Lining soaked with lubricant or hydraulic fluid |
"Correct any leaks then replace lining" |
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| "Hard" Pedal operation |
Brakes out of adjustment |
Adjust brakes |
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Inoperative brake hydrovac |
Replace unit |
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Obstructed hydraulic brake line |
Clean or replace defective line |
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Binding pedal lever |
"Lubricate pedal and lever clevis pin with lubricant then check for free operation or replace spring" |
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| Wheel drum binds |
Wheel drum out of true |
Replace distorted wheel or drum |
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Lining saturated with fluid |
"Correct any leaks then replace lining." |
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Loose lining |
Replace lining |
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| Excessive lining wear |
Foreign material in brake drum |
"Clean drum brake backing plate and shoes with compressed air" |
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Shoe web to hold-down washer gap not set to 0.015 inch |
Check and reset as required |
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Loose wheel bearing |
"Clean pack and tighten or replace bearing." |
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Defective hydrovac control valve (Causing constant pressure on brakes) |
Replace unit |
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Brake drum has hard spots or is deformed |
Replace drum |
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| Slow return of brake pedal |
Broken return spring |
Replace |
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