SUSPENSION GENERAL

 

INFORMATION

 

 These inspections apply to both front and rear suspensions including any optional components fitted.

 

HOW TO INSPECT

The inspections must be carried out with the vehicle over a pit or on a raised lift.

 

The examination of some front suspension components requires the steered wheels to be jacked up as described in Section ‘Suspension, wheel Bearings and Drive Shafts’.

 

CHECKING FOR WEAR OR PLAY

This should normally be checked by the use of the play detector equipment provided, however a small pinch bar may be used to check for wear or play in many of the suspension components covered in this section.

 

CHECKING FOR CORROSION

Guidance for assessing corrosion and the use of the Corrosion Assessment Tool is given at Appendix A ‘Structural Integrity and Corrosion’.

 

MAIN LOAD BEARING STRUCTURE

The condition of the vehicle main load bearing structure not in a ‘prescribed area’ is checked under the section titled General Condition of Vehicle. 

 

CARRYING OUT THIS INSPECTION

The inspections in sub-section G can be carried out in conjunction with the inspections in section titled ‘Suspension, Wheel Bearings and Drive Shaft’.

 

A SUSPENSION BUMP STOP

A suspension bump stop must not be confused with rubber/synthetic suspension spring assistors.

 

AN INAPPROPRIATE REPAIR OR MODIFICATION

An inappropriate repair or modification includes welded repairs or the use of excessive heat to highly stressed components (See Appendix A ‘Structural Integrity and Corrosion’) and modifications which are likely to affect the roadworthiness of the vehicle.

 

 

 

METHOD OF INSPECTION

 

A. ALL SUSPENSION TYPES

 

1. Check

 

• • That there is enough clearance of the axle or suspension with the bump stop or chassis, and

 

• • Whether any suspension unit is so weak that it does not hold the body far enough away from the road wheels.

 

2. Check suspension components for inappropriate repairs or modifications 

 

3. Examine the vehicle structure around any sub-frame, spring or suspension component mounting for:-

 

• • Fractures.

 

• • Distortions.

 

• • Excessive corrosion (i.e., within the ‘prescribed area’, see Appendix A).

 

Note: It is usually necessary to open the bonnet to inspect front suspension components.

It may be necessary to inspect the inside of a luggage compartment or boot to effectively check prescribed areas and testable items that otherwise would not be seen.

 

B. LEAF SPRINGS

 

1. Examine each leaf spring assembly, check:-

 

• • The condition of spring leaves,

 

• • The condition of spring eyes,

 

• • The lateral location of spring leaves (particularly leaf splay),

 

• • Leaves for longitudinal displacement,

 

• • The correct location of the springs to the axle for symmetry.

 

2. Check the security and the amount of play at the spring anchor bracket pin/bushes of the spring shackle.

 

3. Check that:-

 

• • Anchor/shackle pins are correctly positioned and secure,
  • Retaining and any locking devices are present and secure.

 

4. Check the side play at spring eyes.

 

Note:  

For normal leaf suspension, side play at the spring eye should not exceed 6 mm.

 

5. check condition of slipper and rebound pin.

 

6. Check that the spring balance beam, anchor and shackle brackets are:

 

• • Secure and free from signs of movement,

 

Note:  

Attachment of suspension units, e.g., anchor brackets, may be by bolts, nuts, rivets, welding, etc.

 

Note: 

When modified spring anchor or shackle brackets are fitted, there may be more holes in the bracket than holes in the chassis.  This is not a reason for rejection.

 

• • Free from cracks or fractures,

 

• • Complete with all nuts, bolts and rivets,

 

• • Free from excessive damage or corrosion.

 

Note:  

Damage includes damage by weld, e.g. weld blow holes or cuts which seriously weaken the component.

 

7. Check the security of spring and saddle to the axle.

 

C.      COIL SPRINGS

 

1. Examine each spring for general condition.  In particular, look for cracks or fractures.

 

2. Check that both ends of each spring are correctly located.

 

3. Check that the spring mountings area:

 

• • Secure,

 

• • Free from cracks and fractures,

 

• • Free from excessive damage or corrosion.

 

D.      FLUID/GAS SUSPENSION

 

1. Check suspension units and accumulators for:-

 

• • Displacement,

 

• • Damage or serious deterioration,

 

• • Fouling or by moving parts.

 

2. Check for any leak in the system.

 

3. Check suspension units, supply pipes or interconnecting pipes for damage or corrosion.

 

4. Check the security of:-

 

• • Levelling valves,

 

• • Fluid supply pipes and interconnecting pipes.

 

5. At each corner of the vehicle, where practicable, push down (or pull down from underneath), and note the amount of suspension movement.

 

Note: 

Care must be taken not to cause damage to body work when pushing down on the suspension.

 

E. TORSION BARS

 

1. Examine the bars for:

 

• • Cracks and fractures

 

• • Excessive corrosion and pitting.

 

• • Welding or excessive heat.

 

2. Check the end fixings for:

 

• • Security,

 

• • Excessive free play.

 

3. Examine the adjustment assembles for security.

 

4. Check that the attachments of bars are:

 

• • Secure to frame and suspension,

 

• • Free from cracks or fractures,
  • Free from excessive damage or corrosion.

 

F.      BONDED SUSPENSION UNITS

 

1. Check that the attachments of units are:

 

• • Secure,

 

• • Free from cracks and fractures,

 

• • Free from excessive damage or corrosion.

 

2. Examine the bonding of the flexible element to its associated metal fixing.

 

3. Check the general condition of the unit for damage and deterioration of the flexible element.

 

G.     SUSPENSION ARMS AND LINKAGES, SUB-FRAMES, ETC

 

1. Check the following components and any attachment brackets, linkages, members for presence, cracks, fractures, distortion, corrosion, wear and insecurity.

 

• • Suspension arms (wishbone etc),

 

• • Trailing arms,

 

• • Radius arms,

 

• • Tie bars/rods,

 

• • Panhard rods,

 

• • Torque/reaction arms,

 

• • Anti-roll bars and linkages,

 

• • MacPherson strut casings,

 

• • Sub-frames.

 

 

Note:  

Some vehicles use comparatively thin gauge steel pressings for some highly stressed suspension components.

 

Many of these parts have hollow ‘box sections’ or upfacing areas where road dirt impregnated with salt or other chemicals collects and causes serious but often very local corrosion.

 

Special attention should be paid to these components.  See Appendix A for further guidance.

 

2. Check that anti-roll bar is fitted to an axle on which it is standard.

 

Note: 

If the standard suspension has been replaced by another type of suspension which does not include an anti-roll bar, it would not be appropriate to require the fitment of an anti-roll bar that was fitted as standard to that vehicle. Where the new type suspension is fitted with an anti-roll it must function as such. 

 

3. Check the security and the amount of play at pins/bushes and ball joints locating.

 

• • Upper and lower suspension arms/wishbones,

 

• • Trailing arms,

 

• • Radius arms,

 

• • Tie-bars/rods,

 

• • Panhard rods,

 

• • Torque/reaction arms,

 

• • Anti-roll bars and linkages,

 

• • Sub-frames.

 

4. Check that:

 

• • Linkage pins are correctly positioned and secure,

 

• • Retaining and any locking devices are fitted and secure.

 

5. Check the following suspension attachment brackets for security, cracks, fractures, excessive damage or corrosion and tightness of nuts, bolts, etc.

 

• • Suspension arms (wishbone, etc),

 

• • Trailing arms,

 

• • Radius arms,

 

• • Tie bars/rods,

 

• • Panhard rods,

 

• • Torque/reaction arms,

 

• • Anti-roll bars,

 

• • Sub-frames.

 

6. On vehicles which have a drive shaft which forms part of the suspension, check.

 

• • The shaft for distortion, damage and serious corrosion,

 

• • The universal joint bearings for excessive play,

 

• • The flanges and bolts for security.

 

• • For wear in drive shaft support bearings

 

• • The condition and security of drive shaft coupling gaiters.

 

H.     FORK TYPE SUSPENSION

 

1.      Examine the handlebar and fork yokes assembly

 

 

REASON FOR REJECTION

                                                                                                                                       Deficiency Category

 

A.      ALL SUSPENSION TYPES                                                                             

             

1.                                                                                                                                    

1. Inadequate clearance of the axle or suspension with           MAJOR the bump stop or chassis, or

             

2. A suspension unit so weak that the body or other part         DANGEROUS of the vehicle fouls a road wheel or would do so if the vehicle was laden.

          

3. a missing bump stop rubber       MINOR

             

2. A suspension component with an inappropriate repair, or a     MAJOR

modification which has seriously weakened the component.

             

3. Deliberate modification which significantly reduces the            MAJOR

original strength, excessive corrosion, severe distortion, a fracture or an inadequate repair of a load bearing member or its supporting structure or supporting panelling within 30 cm of any sub-frame, spring or a suspension component mounting.  That is, within a ‘prescribed area’, see Appendix A.

             

B. LEAF SPRINGS                                                                                         

             

1.                                                                                                                                  

1. A cracked or fractured leaf, or one which has been           MAJOR

repaired by welding or is permanently distorted due to damage or so deteriorated that it is seriously weakened,

             

2. A defective spring eye,             DANGEROUS

             

3. The leaves of multi-leaf spring splayed to such an            MAJOR

extent that the action of the spring is impaired, or will foul other parts of the vehicle,

             

4. A spring leaf longitudinally displaced,          MAJOR

             

5. A spring so fitted that the axle is misaligned.           MAJOR

             

2. Excessive wear in a pin and/or bush, for example more          MAJOR

than:-

1. 1. 2 mm for a 12 mm dia pin,         
   2. 3 mm for a 25 mm dia pin,         
   3. 10% of the pin dia for pins over 25 mm dia  
   4. deterioration of a rubber bush resulting in excessive         movement.

             

3. A shackle, anchor or linkage pin:              

             

1. 1. Missing, not correctly positioned or excessively loose       MAJOR

in its bracket,

             

1. 2. Retaining or locking device missing or insecure.   MAJOR

             

4. Excessive side play at spring eye.            MAJOR

             

5. A slipper excessively worn, cracked, insecure or its     MAJOR rebound pin missing.

             

6. An anchor or shackle bracket.        

             

1. 1. Loose to chassis,           MAJOR

             

1. 2. Cracked or fractured,    MAJOR

             

1. 3. With a nut, bolt or rivet missing,          MAJOR           
   4. Damaged or corroded so that it is seriously MAJOR weakened.

             

7.                                                                                                                                     

             

1. 1. Evidence that a spring saddle is fractured or moving          MAJOR

relative to the spring,

             

1. 2. A nut or bolt securing the spring to the axle not secure      MAJOR or missing.

             

C.      COIL SPRING                                                                                                    

             

1. A coil spring:    

             

1. 1. Incomplete, cracked or fractured,       MAJOR

             

1. 2. Worn or corroded so that its cross sectional area is            MAJOR

seriously weakened,

             

1. 3. Repaired by welding or damaged by excessive heat.        MAJOR

             

2. A coil spring end not correctly located:       MAJOR

             

3. A coil spring mounting:          

             

1. 1. Loose,      MAJOR

             

1. 2. Cracked or fractured,    MAJOR

             

1. 3. Seriously weakened by damage or corrosion.         MAJOR

             

D.      FLUID/GAS SUSPENSION                                                                             

             

1. A suspension unit or accumulator:              

             

1. 1. Displaced or totally deflated,   DANGEROUS

             

1. 2. Damaged or deteriorated so that it is likely to fail,   MAJOR

             

1. 3. Fouled by moving parts likely to cause damage or             MAJOR restrict travel.

             

2. A leak in the system. MAJOR

             

3. A suspension unit supply pipe or interconnecting pipe MAJOR damaged or corroded so that it is seriously weakened.

             

4.                                                                                                                                    

1. 1. An insecure levelling valve,    MAJOR

             

1. 2. An insecure fluid supply pipe or interconnecting pipe.     MAJOR

             

5. No suspension movement.                                                                      MAJOR

             

Note:               Large vehicle suspensions can be difficult to move.  Ensure             there is a defect before rejection.

             

E. TORSION BARS                                                                                        

             

1. A torsion bar:    

             

1. 1. Cracked or fractured,    MAJOR

             

1. 2. Deteriorated by corrosion or pitting so that its cross            MAJOR section area is reduced and seriously weakened.

             

1. 3. Repair by welding or damaged by excessive heat.             MAJOR

             

2. Insecurity or excessive play at an end fixing.       MAJOR

             

3. Adjustment assembly inadequately locked.          MAJOR

             

4. A torsion bar attachment bracket:     

             

1. 1. Loose,      MAJOR

             

1. 2. Cracked or fractured,    MAJOR

             

1. 3. Seriously weakened by damage or by corrosion.    MAJOR

             

F. BONDED SUSPENSION UNITS                                                             

             

1. A bonded unit attachment:    

             

1. 1. Loose,      MAJOR

             

1. 2. Cracked or fractured,    MAJOR

             

1. 3. Seriously weakened by damage or corrosion.         MAJOR

             

2. Failure of the bonding between flexible element and the          MAJOR metal so that part of unit is likely to become displaced.

             

3. The unit is so damaged or deteriorated that it is no longer         DANGEROUS capable of carrying out its proper function.        

G.      SUSPENSION ARMS AND LINKAGES, SUB-FRAMES,                          

ETC                                                                                                 

             1.        A suspension component or its attachment bracket,     linkage or member:

             

1. Missing where one is fitted as standard           MAJOR

             

2. Cracked, fractured or insecure, MAJOR

             

3. Severely distorted,            MAJOR

             

4. Seriously weakened by corrosion or wear,      MAJOR

             

5. Which is adjustable and is loose in its adjustment     MAJOR threads, or its locking device insecure or missing,

             

6. Inadequately repaired (see Appendix A),         MAJOR

             

7. Seriously weakened as a result of deliberate MAJOR modification.

             

2.      An anti-roll bar not fitted to an axle on which it is standard.                      MAJOR

             

Note:                                                                                                                              

If the standard suspension has been replaced by another type of     suspension which does not include an anti-roll bar, it would not be appropriate to require the fitment of an anti-roll bar that was fitted as standard to that vehicle. Where the new type suspension is fitted with an anti-roll it must function as such. 

             

3.                                                                                                                                    

1. Excessive play in a pin/bush or pin/bearing, for MAJOR example more than:
   • 2 mm for a 12 mm diameter pin,     
   • 3 mm for a 25 mm diameter pin,     
   • 10% of the diameter for pins over 25 mm diameter,        

             

2. Excessive play in a ball joint, MAJOR

             

3. Deterioration of a rubber synthetic bush or mounting        MAJOR resulting in excessive movement.

             

4. Deterioration of the bonding of a rubber       MAJOR bush/mounting resulting in excessive movement.

             

5. A ball joint dust cover deteriorated     MINOR

 

6. A ball joint dust cover missing or excessively          MAJOR

damaged, deteriorated or insecure to the extent that it

would no longer prevent the ingress of dirt etc.

             

Note:                                                                                                                  

Some rubber/synthetic bushes, are designed to provide a                      

comparatively high degree of compliance.  They are therefore likely to show some movement.     Such components should normally only be rejected when 

serious deterioration of the bonding or flexible material is evident.

             

4. A suspension link locating pin:        

             

1. 1. Incorrectly positioned or insecure,     MAJOR

             

1. 2. Retaining or locking device missing or not properly           MAJOR locked.

             

5. A suspension attachment linkage bracket or mounting:              

             

1. 1. Insecure,             MAJOR

             

1. 2. Cracked or fractured,    MAJOR

             

1. 3. Damaged, corroded or worn to such an extent that its       DANGEROUS strength is seriously reduced,

             

1. 4. Nut, bolt or rivet missing, or weld cracked,    MAJOR

             

1. 5. Inadequately repaired (see Appendix A),     MAJOR

             

1. 6. Seriously weakened as a result of deliberate          MAJOR modification.

             

6.                                                                                                                                  

1. 1. A distorted, damaged or excessively corroded drive           MAJOR

shaft,

             

1. 2. Excessive play in a universal joint bearing MAJOR

           c.           A universal joint:       

• • • flange incorrectly seated    MAJOR
    • flange bolt loose, missing or inadequately locked         MAJOR

             

1. 4. A drive shaft support bearing excessively worn      MAJOR

             

1. 5. A drive shaft coupling gaiter missing or excessively          MAJOR

damaged, deteriorated or insecure to the extent that it would no longer prevent the ingress of dirt etc.      

H. FORK TYPE SUSPENSION                                                                                

             

1.      A fork assembly component which is                                                             

1. Missing     MAJOR

             

2. Loose        MAJOR

             

3. Cracked    MAJOR

             

4. Excessive bent, misaligned, corroded, worn, or has            MAJOR excessive free play between the sliding members of the forks, the pivot bearing or bushes.

             

5. Restricted in operation DANGEROUS

             

6. fouling      MAJOR