G EN ER A L IN F O R M A TIO N A ND LU B R IC A TIO N 0-11
PROPELLER SHAFT SLIP JOINTS
Inspection of Brake Lining
Propeller shaft slip joints should be lubricated every 6,000 miles w ith w ater resistant EP chassis grease w hich m eets General M otors Specifications GM 6 0 3 1M.
C A U T IO N :
Brake linings should be periodically
inspected fo r wear. The frequency of this inspection depends upon driving conditions such as tra ffic or terrain, and also the driving techniques o f individual customers.
BRAKES Automatic Brake Adjusters
PARKING BRAKE Every 6,000 miles clean and lubricate all parking brake pivot points w ith w ater resistant EP chassis grease w hich m eets General M otors Specification N o. GM 6 0 3 1M.
Most trucks w ith hydraulic brakes are equipped w ith selfadjusting brakes w hich elim inate periodic brake adjustm ents. THE SELF-ADJUSTING MECHANISM IS ACTUATED, AS NEEDED, WHENEVER THE TRUCK IS MOVED IN RE VERSE AND THE BRAKES ARE APPLIED.
POWER BRAKE VACUU M UNITS H Y D R A U L IC BRAKE SYSTEM The service brake and parking brake systems are designed for braking perform ance under a wide range o f driving condi tions even w hen the vehicle is loaded to its full rated vehicle load. C A U T IO N :
Driving
through
deep
water
may
T rucks equipped w ith pow er brakes utilize engine vacuum to reduce the braking effo rt to much less th an is required with regular brakes. A built-in vacuum reserve will supply tw o or more pow er assisted brake applications after th e engine has stopped. A fter the vacuum reserve has been exhausted, the vehicle can be stopped utilizing the m anual p o rtio n o f the pow er brake system although considerably m ore fo o t pressure will be needed to stop the vehicle.
affect brake performance. T o assure normal opera tion after being w etted, service brakes must be dried. T o dry them quickly, lightly apply the brakes
WHEELS AND TIRES
w hile maintaining a slow forw ard speed until brake perform ance returns to normal.
The service brakes on vehicles equipped w ith a split system are designed so th at in the event o f a hydraulic fluid leak in one-half o f the system , th e other h alf still provides braking action. A brake system w arning light is located in the in stru m ent cluster. The function o f this light is to indicate a m alfunction in the regular braking system . In the event o f broken brake lines, m ajor brake fluid loss, air in the brake lines or a pressure deviation betw een the fro n t and the rear wheel brake lines, the light will com e on and stay on while braking. In this event, the vehicle should n o t be driven until the cause has been determ ined and, if necessary, corrected. Vehicles equipped w ith pow er brakes use engine vacuum to reduce the braking effo rt. The system has a vacuum reserve w hich will supply tw o or m ore pow er assisted brake applica tions after the engine has stopped. A fter th e vacuum reserve has been exhausted, th e vehicle can still be stopped by using greater pedal force. The C hevrolet braking system requires very little care; how ever, the system should be checked occasionally for indications o f fluid leak. I f leaks are found the necessary repairs should be m ade at once. Keep the brakes properly adjusted. Check all vacuum hose connections for leakage.
WHEEL NU T T O R Q U E S On a new vehicle or after the wheel has been changed, the wheel n ut torque m ust be checked at 100, 1,000 and 6,000 miles and every 6,000 miles thereafter. R etorque wheel n u ts to 55-75 ft. lbs. on 10-20 Series and 65 to 90 ft. lbs. for 30 Series models.
WHEEL BEARINGS NOTE: Use high melting point wheel bearing lub ricant which meets General Motors Specification No. GM 60 3 1 M .
Front D ue to the w eight o f the tire and wheel assembly it is recom m ended th a t they be removed from hub before lubri cating bearings to prevent damage to oil seal. T hen remove the fro n t wheel hub to lubricate the bearings. The bearings should be thoroughly cleaned before repacking w ith lubricant. F ro n t wheels are equipped w ith tapered roller bearings on all trucks. Wheel bearings should be lubricated every 30,000 miles. Do n o t m ix wheel bearing lubricants. C A U T IO N :
Master Cylinder Check m aster cylinder fluid level in b o th reservoirs every 6,000 miles. If the fluid is low in the reservoir, it should be filled to a po in t ab o u t 1 /4 " from the top rear o f each reservoir w ith G.M. Suprem e No. 11 H ydraulic Brake Fluid or equiv alent.
"Long fib re " type greases should not
be used on roller bearing fro n t wheels.
Rear The rear wheel bearings receive their lubrication from the rear axle. When installing bearings which have been cleaned, repack w ith lubricant.
C H E V Y V A N SHOP M A N U A L
