PRATT Industries TRUSS - Wheels, Tires and Alignment

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1. Low Air Pressure
1. Check air line connections & verify sufficient
air in tank
2. Brake shoes bound up at cams 2. Lubricate brake-operating parts.
3. Brake hoses restricted 3. Replace hoses.
4. Brake out of adjustment. 4. Adjust brakes.
5. Damaged brake assembly. 5. Contact PRATT
NO BRAKES OR INSUFFICIENT BRAKES
Probable Cause Remedy
1. Source of air supply shut off at 1. Push control valve IN
Tractor
2. Low brake line pressure
2. Check air pressure gauge on tractor -
Inoperative compressor
3. Brake lines between tractor and trailer not
properly coupled
3. Properly couple brake lines
4. Reservoir drain cock open 4. Close drain cock.
SLOW BRAKE APPLICATION OR RELEASE
Probable Cause Remedy
1. Lack of lubrication 1. Lubricate brake operating parts
2. Excessive travel in brake chamber 2. Adjust brakes
3. Restriction in hose or line 3. Replace brake hose or line
4. Defective brake valve 4. Replace brake valve
BRAKES GRABBING
Probable Cause Remedy
1. Foreign material on brake lining 1. Reline brakes
2. Brakes out of adjustment 2. Adjust brakes
3. Brake drum out-of-round 3. Replace brake drum
4. Damaged brake chamber or internal assembly 4. See your nearest Pratt Service
5. Leaky or broken hose between relay valve and
brake chamber
5. Replace or repair as required
BRAKES DRAGGING
Probable Cause Remedy
1. Out of adjustment 1. Adjust brakes
2. Binding cam, anchor pins or chamber rod end
pin
2. Lubricate and free up
3. Damaged brake assembly or brake drum out-of-
round
3. Replace. See PRATT
Wheels, Tires and Alignment
PULLING HARD
P
robable Cause Remedy
1. Broken or cracked spring 1. Replace complete spring
2. Uneven load distribution 2. Rearrange load for proper distribution
3. Weak spring 3. Replace complete spring
4. Axle out of alignment 4. Align axles
WHEELS, HUBS AND TIRES