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

A. All Suspension Types

		Reason for Rejection	Deficiency  Category
1	a	Inadequate clearance of the axle or suspension with the bump stop or chassis, or	MAJOR
	b	A suspension unit so weak that the body or other part of the vehicle fouls a road wheel or would do so if the vehicle was laden.	DANGEROUS
	c	a missing bump stop rubber	MINOR
2		A suspension component with an inappropriate repair, or a modification which has seriously weakened the component.	MAJOR
3		Deliberate modification which significantly reduces the 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.	MAJOR

B. Leaf Springs

		Reason for Rejection	Deficiency  Category
1	a	A cracked or fractured leaf, or one which has been repaired by welding or is permanently distorted due to damage or so deteriorated that it is seriously weakened,	MAJOR
	b	A defective spring eye,	DANGEROUS
	c	The leaves of multi-leaf spring splayed to such an extent that the action of the spring is impaired, or will foul other parts of the vehicle,	MAJOR
	d	A spring leaf longitudinally displaced	MAJOR
	e	A spring so fitted that the axle is misaligned	MAJOR
2		Excessive wear in a pin and/or bush, for example more than:-  a. 2 mm for a 12 mm dia pin,  b. 3 mm for a 25 mm dia pin,  c. 10% of the pin dia for pins over 25 mm dia  d. deterioration of a rubber bush resulting in excessive movement.	MAJOR
3		A shackle, anchor or linkage pin:
	a	Missing, not correctly positioned or excessively loose  in its bracket,	MAJOR
	b	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  rebound pin missing.	MAJOR
6		An anchor or shackle bracket:	MAJOR
	a	Loose to chassis	MAJOR
	b	Cracked or fractured,	MAJOR
	c	With a nut, bolt or rivet missing,	MAJOR
	d	Damaged or corroded so that it is seriously weakened.	MAJOR
7	a	Evidence that a spring saddle is fractured or moving relative to the spring,	MAJOR
	b	A nut or bolt securing the spring to the axle not secure  or missing.	MAJOR

C. Coil Spring

		Reason for Rejection	Deficiency  Category
1		A coil spring:
	a	Incomplete, cracked or fractured,	MAJOR
	b	Worn or corroded so that its cross sectional area is seriously weakened,	MAJOR
	c	Repaired by welding or damaged by excessive heat.	MAJOR
2		A coil spring end not correctly located	MAJOR
3		A coil spring mounting:
	a	Loose,	MAJOR
	b	Cracked or fractured,	MAJOR
	c	Seriously weakened by damage or corrosion.	MAJOR

 D. Fluid/Gas Suspension

		Reason for Rejection	Deficiency  Category
1		A suspension unit or accumulator:
	a	Displaced or totally deflated,	DANGEROUS
	b	Damaged or deteriorated so that it is likely to fail,	MAJOR
	c	Fouled by moving parts likely to cause damage or restrict travel.	MAJOR
2		A leak in the system.	MAJOR
3		A suspension unit supply pipe or interconnecting pipe damaged or corroded so that it is seriously weakened.	MAJOR
4	a	An insecure levelling valve	MAJOR
	b	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

		Reason for Rejection	Deficiency  Category
1		A torsion bar:
	a	Cracked or fractured,	MAJOR
	b	Deteriorated by corrosion or pitting so that its cross section area is reduced and seriously weakened.	MAJOR
	c	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:
	a	Loose,	MAJOR
	b	Cracked or fractured,	MAJOR
	c	Seriously weakened by damage or by corrosion.	MAJOR

F. Bonded Suspension Units

		Reason for Rejection	Deficiency  Category
1		A bonded unit attachment:
	a	Loose,	MAJOR
	b	Cracked or fractured,	MAJOR
	c	Seriously weakened by damage or corrosion.	MAJOR
2		Failure of the bonding between flexible element and the metal so that part of unit is likely to become displaced.	MAJOR
3		The unit is so damaged or deteriorated that it is no longer capable of carrying out its proper function.	DANGEROUS

G. Suspension Arms and Linkages, Sub-Frames, etc

		Reason for Rejection	Deficiency  Category
1		A suspension component or its attachment bracket, linkage or member:
	a	Missing where one is fitted as standard	MAJOR
	b	Cracked, fractured or insecure,	MAJOR
	c	Severely distorted,	MAJOR
	d	Seriously weakened by corrosion or wear,	MAJOR
	e	Which is adjustable and is loose in its adjustment threads, or its locking device insecure or missing,	MAJOR
	f	Inadequately repaired (see Appendix A),	MAJOR
	g	Seriously weakened as a result of deliberate modification.	MAJOR
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.

		Reason for Rejection	Deficiency  Category
3	a	Excessive play in a pin/bush or pin/bearing, for 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 di	MAJOR
	b	Excessive play in a ball joint,	MAJOR
	c	Deterioration of a rubber synthetic bush or mounting resulting in excessive movement.	MAJOR
	d	Deterioration of the bonding of a rubber bush/mounting resulting in excessive movement.	MAJOR
	e	A ball joint dust cover deteriorated	MINOR
	f	A ball joint dust cover missing or excessively damaged, deteriorated or insecure to the extent that it would no longer prevent the ingress of dirt etc.	MAJOR

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.

		Reason for Rejection	Deficiency  Category
4		A suspension link locating pin:
	a	Incorrectly positioned or insecure,	MAJOR
	b	Retaining or locking device missing or not properly locked.	MAJOR
5		A suspension attachment linkage bracket or mounting:
	a	Insecure,	MAJOR
	b	Cracked or fractured,	MAJOR
	c	Damaged, corroded or worn to such an extent that its strength is seriously reduced,	DANGEROUS
	d	Nut, bolt or rivet missing, or weld cracked,	MAJOR
	e	Inadequately repaired (see Appendix A),	MAJOR
	f	Seriously weakened as a result of deliberate modification.	MAJOR
6	a	A distorted, damaged or excessively corroded drive shaft,	MAJOR
	b	Excessive play in a universal joint bearing	MAJOR
	c	A universal joint:
		• flange incorrectly seated	MAJOR
		• flange bolt loose, missing or inadequately locked	MAJOR
	d	A drive shaft support bearing excessively worn	MAJOR
	e	A drive shaft coupling gaiter missing or excessively damaged, deteriorated or insecure to the extent that it would no longer prevent the ingress of dirt etc.	MAJOR

H. Fork Type Suspension

		Reason for Rejection	Deficiency  Category
1		A fork assembly component which is:
	a	Missing	MAJOR
	b	Loose	MAJOR
	c	Cracked	MAJOR
	d	Excessive bent, misaligned, corroded, worn, or has excessive free play between the sliding members of the forks, the pivot bearing or bushes.	MAJOR
	e	Restricted in operation	DANGEROUS
	f	fouling	MAJOR