Fault finding REF•15
REF
9 Suspension and steering systems
Note: Before diagnosing suspension or steering faults, be sure that the
trouble is not due to incorrect tyre pressures, mixtures of tyre types, or
binding brakes.
Vehicle pulls to one side
mm Defective tyre (“Weekly checks”).
mm Excessive wear in suspension or steering components (Chapters 1
and 10).
mm Incorrect front wheel alignment (Chapter 10).
mm Worn or broken subframe mountings (Chapter 10).
mm Accident damage to steering or suspension components (Chapter 1).
Wheel wobble and vibration
mm Front roadwheels out of balance (vibration felt mainly through the
steering wheel) (Chapters 1 and 10).
mm Rear roadwheels out of balance (vibration felt throughout the
vehicle) (Chapters 1 and 10).
mm Roadwheels damaged or distorted (Chapters 1 and 10).
mm Defective tyre (“Weekly checks” ).
mm Worn steering or suspension joints, bushes or components
(Chapters 1 and 10).
mm Wheel nuts loose (Chapters 1 and 10).
Excessive pitching and/or rolling around corners,
or during braking
mm Defective shock absorbers - rubber cone suspension models
(Chapter 10).
mm Incorrect vehicle ride height - Hydrolastic suspension models
(Chapter 10).
mm Worn or damaged suspension component or mounting (Chapter 10).
Wandering or general instability
mm Incorrect front wheel alignment (Chapter 10).
mm Worn steering or suspension joints, bushes or components
(Chapters 1 and 10).
mm Roadwheels out of balance (Chapters 1 and 10).
mm Defective tyre (“Weekly checks”).
mm Wheel nuts loose (Chapters 1 and 10).
mm Defective shock absorbers - rubber cone suspension models
(Chapter 10).
mm Incorrect vehicle ride height - Hydrolastic suspension models
(Chapter 10).
Excessively-stiff steering
mm Lack of steering gear lubricant (Chapter 10).
mm Seized tie-rod or suspension balljoint (Chapters 1 and 10).
mm Incorrect front wheel alignment (Chapter 10).
mm Steering rack or column bent or damaged (Chapter 10).
Excessive play in steering
mm Worn steering tie-rod balljoints (Chapters 1 and 10).
mm Loose steering column clamp bolt (Chapter 10).
mm Worn rack-and-pinion steering gear (Chapter 10).
mm Worn steering or suspension joints, bushes or components
(Chapters 1 and 10).
Tyre wear excessive
Tyres worn on inside or outside edges
mm Tyres under-inflated (wear on both edges) (“Weekly checks”).
mm Incorrect camber or castor angles (wear on one edge only)
(Chapter 10).
8 Braking system
Note: Before assuming that a brake problem exists, make sure that the
tyres are in good condition and correctly inflated, that the front wheel
alignment is correct, and that the vehicle is not loaded with weight in an
unequal manner.
Vehicle pulls to one side under braking
mm Worn, defective, damaged or contaminated brake shoes/pads on
one side (Chapters 1 and 9).
mm Seized or partially-seized front wheel cylinder piston or brake
caliper piston (Chapters 1 and 9).
mm A mixture of brake shoe/ pad lining materials fitted between sides
(Chapters 1 and 9).
mm Brake backplate or caliper mounting bolts loose (Chapter 9).
mm Worn or damaged steering or suspension components
(Chapters 1 and 10).
Noise (grinding or high-pitched squeal) when
brakes applied
mm Brake shoe or pad friction lining material worn down to metal
backing (Chapters 1 and 9).
mm Excessive corrosion of brake drum or disc. (May be apparent after
the vehicle has been standing for some time (Chapters 1 and 9).
Excessive brake pedal travel
mm Incorrect drum brake adjustment (Chapter 1).
mm Faulty master cylinder (Chapter 9).
mm Air in hydraulic system (Chapter 9).
mm Faulty vacuum servo unit - where fitted (Chapter 9).
Brake pedal feels spongy when depressed
mm Air in hydraulic system (Chapter 9).
mm Deteriorated flexible rubber brake hoses (Chapters 1 and 9).
mm Master cylinder mounting nuts loose (Chapter 9).
mm Faulty master cylinder (Chapter 9).
Excessive brake pedal effort required to stop
vehicle
mm Faulty vacuum servo unit - where fitted (Chapter 9).
mm Disconnected, damaged or insecure brake servo vacuum hose
(Chapter 9).
mm Primary or secondary hydraulic circuit failure (Chapter 9).
mm Seized wheel cylinder or brake caliper piston(s) (Chapter 9).
mm Brake shoes or pads incorrectly fitted (Chapters 1 and 9).
mm Incorrect grade of brake shoes or pads fitted (Chapters 1 and 9).
mm Brake shoe linings or pads contaminated (Chapters 1 and 9).
Judder felt through brake pedal or steering wheel
when braking
mm Excessive run-out or distortion of drums/discs (Chapters 1 and 9).
mm Brake shoe or pad linings worn (Chapters 1 and 9).
mm Brake backplate or caliper mounting bolts loose (Chapter 9).
mm Wear in suspension or steering components or mountings
(Chapters 1 and 10).
Brakes binding
mm Incorrect drum brake adjustment (Chapter 1).
mm Seized wheel cylinder or brake caliper piston(s) (Chapter 9).
mm Incorrectly-adjusted handbrake mechanism (Chapter 9).
mm Seized handbrake cable moving sectors (Chapter 9).
mm Faulty master cylinder (Chapter 9).
Rear wheels locking under normal braking
mm Rear brake shoe linings contaminated (Chapters 1 and 9).
mm Faulty brake pressure regulating valve or reducing valve (Chapter 9).
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