Part 1
Standard Workshop Practices
Vehicle in Workshop
When working on a vehicle in the workshop always make sure that:
^ Where practicable, the parking brake is applied and the wheels are securely chocked to prevent the vehicle moving forwards or backwards.
^ Whenever possible, the ignition key is removed before any work is carried out on the vehicle.
^ If the engine is to be run, there is adequate ventilation, or an extraction hose is used to remove exhaust fumes.
^ There is adequate room to raise the vehicle and remove the wheels, if necessary.
^ Fender covers are always fitted if any work is to be carried out in the engine compartment.
^ Where practicable, the battery is disconnected if working on the engine, underneath the vehicle, or if the vehicle is raised.
CAUTION:
^ Prior to disconnecting the battery, refer to the Electrical Section of this manual - Battery disconnection/connection.
^ When electric arc welding on a vehicle, always disconnect the generator wiring to prevent the possibility of a surge of current causing damage to the internal components of the generator.
^ If using welding equipment on the vehicle, a suitable fire extinguisher is readily available.
Battery - General
CAUTION:
^ Prior to carrying out any procedures which involve disconnecting/ or connecting the battery, refer to the Electrical Section of this manual - Battery disconnection/connection.
^ A discharged battery condition may have been caused by an electrical short circuit. If this condition exists there will be an apparently live circuit on the vehicle even when all normal circuits are switched off. This can cause arcing when the jumper cables are connected.
^ While it is not recommended that the vehicle is jump started, it is recognized that this may occasionally be the only practical way to mobilize a vehicle. Prior to attempting a jump start, reference must be made to the Electrical Section of this manual - Jump Starting.
Following jump starting of a disabled vehicle, the discharged battery must be checked for serviceability and recharged off the vehicle as soon as possible to avoid permanent damage.
Do not rely on the generator to restore a discharged battery. For a generator to recharge a battery, it would take in excess of eight hours continuous driving with no additional loads placed on the battery.
^ Always make sure that the jumper cables are adequate for the task.
^ Always make sure that the slave battery is of the same voltage as the vehicle battery. The batteries must be connected in parallel.
^ Always make sure that switchable electric circuits are switched off before connecting jumper cables. This reduces the risk of arcing occurring when the final connection is made.
Towing the Vehicle
WARNING: When towing is necessary, reference must be made to the Jacking, Lifting and Towing Section of this Manual. When the vehicle is being towed dock the remote control and switch on the ignition, (steering lock released and warning lights illuminated). Only then will the steering, turn signal lamps, horn and stop lamps be operational. Failure to follow these instructions may result in personal injury. It must be noted that with the engine not running, the power steering and brake booster will be inoperative therefore, greater effort will be needed to steer the vehicle and apply the brakes.
General Fitting Instructions
Component removal
Whenever possible, clean components and the surrounding area before removal.
^ Blank off openings exposed by component removal.
^ Following disconnection, seal fuel, oil or hydraulic lines immediately using suitable blanking plugs or caps.
^ Seal open ends of exposed oilways using suitable tapered hardwood plugs or conspicuous plastic plugs.
^ Immediately a component is removed, place it in a suitable container; use a separate container for each component and its associated parts.
^ Clean bench and provide marking materials, labels and containers before disassembling components.
Disassembling
Observe scrupulous cleanliness when disassembling components, particularly when brake, fuel, air suspension or hydraulic system parts are disassembled. A particle of dirt or cloth fragment could cause a serious malfunction if trapped in these systems.
^ Blow out all tapped holes, crevices, oilways and fluid passages with dry, compressed air.
WARNING: Suitable eye protection must be worn.
^ Discard all seals and O-rings and replace with new when reassembling.
^ Use suitable marker ink to identify mating parts, do not use a scriber or center punch as they could initiate cracks or distortion.
^ Wire or tape mating parts together where necessary to prevent accidental interchange.
^ Suitably identify parts which are to be renewed and to those parts requiring further inspection. Keep these parts separate.
^ To ensure that the correct replacement part has been obtained, do not discard a part due for renewal until after comparing it with the new part.
Cleaning Components
Always use cleaning agents which are suitable for the work being undertaken and the components being cleaned. NEVER use gasoline (petrol) as a cleaning agent (degreaser). Always ensure that the component being cleaned is compatible with the cleaning agent.
Always follow the manufacturer's instructions regarding the use of cleaning agents and ensure that the environment in which the work is being undertaken is suitable. See Health and Safety Precautions for further information regarding cleaning.
General Inspection of Components
All components should be inspected for wear or damage before reassembling.
^ Always ensure that component to be inspected is clean and free from oil or grease.
^ When a component is to be checked dimensionally against design specified values, use the appropriate measuring equipment i.e. micrometers, verniers, surface plates, dial test indicators (DTI).
^ Always ensure that all measuring equipment is correctly calibrated before use.
^ Reject a component which is not within specified values/limits or if it appears to be damaged.
^ A component may be refitted if dimensions obtained during checking are at the maximum tolerance limit and it is in an undamaged condition.
^ Bearing journal clearances should be checked where necessary using Plastigauge.
Joints and Joint Faces
All gaskets should be fitted dry unless stated otherwise. Always fit new O-rings when reassembling components, always apply the specified lubricant to O-rings and fit O-rings using the fingers only.
Use gasket removal spray and/or plastic scrapers to remove traces of old gasket.
CAUTION: DO NOT use metal scrapers or emery cloth as these may damage the sealing surfaces.
Many joints use sealants instead of gaskets as the sealing medium. Where this is the case, the sealant together with its part number will be found listed in the relevant repair operation and also in the sealants table.
CAUTION: Always remove all traces of the old sealant prior to reassembly. Use plastic scrapers, specified solvents where available or dry, lint free cloth. DO NOT use metal scrapers or emery cloth as these may damage the sealing surfaces. Ensure that sealing surfaces are free from oil or grease as sealants will not adhere properly to contaminated surfaces.
Do not allow sealant to enter tapped holes or oilways.
Locking Devices
Always replace locking devices with one of the same design and of the correct size.
Tab washers
Always release locking tabs before loosening fixings, do not reuse tab washers.
Locknuts
Always use a backing spanner when loosening and tightening locknuts, brake and fuel pipe unions.
Roll pins
Always fit new roll pins of the correct size.
Circlips
Always fit new circlips ensuring that they are of the correct size for the groove.
Woodruff keys
Woodruff keys may be reused provided there is no indication of wear or distortion. Remove any burrs from edges of keyways using a fine file.
Split pins
Never attempt to straighten and reuse a split pin, always ensure that replacement pins are of the correct size for the hole in which they are to be fitted.
Screw Threads
^ Damaged nuts, bolts and screws must always be discarded. Attempting to recut or repair damaged threads with a tap or die impairs the strength and fit of the threads and is not recommended.
NOTE: During certain repair operations, it may be necessary to remove traces of thread locking agents using a tap. Where this is necessary, the instruction to do so will appear in the relevant operation and it is essential that a tap of the correct size and thread is used.
^ Some bolts are coated with a thread locking agent and unless stated otherwise, they must not be reused. New bolts having the same part number as the original must always be fitted. When nuts or bolts are to be discarded, the repair operation and relevant torque chart will include an instruction to that effect. Do not use proprietary thread locking agents as they may not meet the specification required. See also Encapsulated ('Patched') Bolts and Screws.
^ Always ensure that replacement nuts and bolts are at least equal in strength to those that they are replacing. Castellated nuts must not be loosened to accept a split pin except in recommended cases when this forms part of an adjustment.
^ Do not allow oil or grease to enter blind holes, the hydraulic action resulting from tightening the bolt or stud can split the housing and also give a false torque reading.
^ Always tighten a nut, bolt or screw to the specified torque figure, damaged or corroded threads can give a false torque reading.
^ Nut and bolt loosening and tightening sequences, where given, must ALWAYS be followed. Distortion of components or faulty sealing of joints will result if the sequences are not followed. Where an instruction is given to tighten in stages, these stages must be adhered to; do not attempt to combine stages particularly where certain stages involve tightening by degrees.
^ To check or re-tighten a fixing to a specified torque, first loosen a quarter of a turn, then retighten to the specified torque figure.
^ Unless instructed otherwise, do not lubricate bolt or nut threads prior to fitting.
Where it is stated that bolts and screws may be reused, the following procedures must be carried out:
^ Check that threads are undamaged.
^ Remove all traces of locking agent from the threads.
CAUTION: DO NOT use a wire brush; take care that threads are not damaged.
^ Ensure that threads are clean and free from oil or grease.
^ Apply the specified locking agent to the bolt threads.
Bolt and Nut Identification
An ISO metric bolt or screw made of steel and larger than 6 mm in diameter can be identified by either of the symbols ISO M or M embossed or indented on top of the bolt head.
In addition to marks identifying the manufacturer, the top of the bolt head is also marked with symbols indicating the strength grade e.g. 8.8, 10.9, 12.9, 14.9. Alternatively, some bolts and screws have the M and strength grade symbol stamped on the flats of the hexagon.
Encapsulated ('Patched') bolts and screws
Encapsulated ('patched') bolts and screws have a thread locking agent applied to the threads during manufacture. Most thread locking agents are colored, the band of color extending for 360 degrees around the thread. Some locking agents however, are neutral in color and may not be so easily identified apart from a slightly darker area of thread where the locking agent has been applied. The locking agent is released and activated by the tightening process and is then chemically cured to provide the locking action.
Self-locking bolts and screws
Unless stated in a specific repair procedure, self-locking bolts and screws i.e. nylon patched or trilobular thread can be reused provided that resistance is felt when the locking portion enters the female thread.
Nylon patched bolts and screws have a locking agent either applied to, or inserted in the threaded portion. They are identified by the presence of a colored section of thread extending approximately 180 degrees around the thread or by a colored plug inserted into the bolt.
Trilobular bolts have a special thread form which creates a slight interference with the thread of the hole or nut into which it is screwed.
CAUTION: Do Not reuse self-locking fasteners in critical locations e.g. drive plates/flywheel or engine bearings. Do not fit non self-locking fasteners where a self-locking fastener is specified.
Trilobular bolts should not be used as a substitute for patched bolts.
Nut identification
A nut with an ISO metric thread is marked on one face or one of the hexagonal flats with the strength grade symbol 8, 12, 14. Some nuts with the strength grade 4, 5 or 6 are also marked and some have the metric symbol M on the hexagonal flat opposite the strength grade marking.
A clock face system is sometimes used as an alternative method of indicating the strength grade. The external chamfers or a face of the nut is marked in a position relative to the appropriate hour mark on a clock face to indicate the strength grade.
A dot is used to locate the 12 o'clock position and a dash to indicate the strength grade. If the grade is above 12, two dots identify the 12 o'clock position.
When tightening a slotted or castellated nut, never loosen it to insert a split pin except where specified as part of an adjustment procedure. If difficulty is experienced in correctly positioning the slot, alternative washers or nuts should be selected.
Where a nut is tightened to adjust or maintain bearing pre-load, the tightening procedure must be adhered to.
Self-locking nuts
Unless stated in a specific repair procedure, self-locking nuts i.e. those with a nylon insert or deformed thread nuts can be reused provided that resistance can be felt when the locking portion of the nut passes over the thread of the bolt or stud.
Unless stated otherwise, self-locking nuts once removed must be discarded and new nuts of the same type and strength grade fitted.
Ball and Roller Bearings
When removing and installing bearings, ensure that the following practices are observed to ensure component serviceability:
CAUTION: Service tools have been developed for removing the majority of bearings; these must always be used where specified.
^ Remove all traces from bearing under inspection by cleaning with a suitable degreasant; maintain absolute cleanliness throughout operations.
^ Conduct a visual inspection for markings on rolling elements, raceways, outer surfaces of outer or inner surfaces of inner rings. Reject any bearings found to be marked since marking in these areas indicates onset of wear.
^ Hold inner race of bearing between finger and thumb of one hand and rotate outer race to check that it revolves absolutely smoothly. Repeat holding outer race and rotating inner race. DO NOT spin the bearing.
^ Rotate outer ring gently using a reciprocating movement whilst holding inner ring; feel for any check or obstruction to rotation. Reject bearing if movement is not absolutely smooth.
^ Check bearing for blueing or signs of overheating.
^ Lubricate bearing with the specified lubricant.
^ Inspect bearing surface of shaft and bearing housing for discoloration or other markings which indicate overheating of bearing or movement between bearing and seating.
^ Before fitting bearing, ensure that shaft and bearing housing are clean and free from burrs.
^ If one bearing of a pair shows signs of wear, overheating etc., it is advisable to replace bearings as a pair unless it is suspected that one bearing may have been faulty when fitted, was fitted incorrectly or the fault arose due to oil seal failure.
^ Never refit a bearing unless it is in a fully serviceable condition.
^ When fitting a bearing to a shaft, only apply force to the inner ring of the bearing. When fitting a bearing into a housing, only apply force to the outer ring of the bearing.
CAUTION: Service tools have been developed for fitting the majority of bearings; these must always be used where specified.
^ In the case of grease lubricated bearings, fill the space between the bearing and outer seal with the recommended grade of grease before fitting the seal.
CAUTION: When a waxed oil seal (fitted dry) type of oil seal is to be fitted, take great care that grease does not contaminate the running surface of the seal.
^ Always make suitable reference marks between the components of separable bearings e.g. taper roller bearings when disassembling to ensure correct location of components when assembling. Never fit new rollers in an outer ring, always fit a new bearing assembly.
Brake Pads and Linings
Always fit the correct grade and specification of brake pads and linings. When replacing these items, always replace as complete axle sets.
Brake Hydraulics
Always observe the following recommendations when working on the braking system:
WARNING: Do not intermix brake fluid of different specifications.
^ Always use two spanners when loosening or tightening brake pipes or hose connections.
^ Ensure that hoses run in a natural curve and are not kinked or twisted.
^ Fit brake pipes and hoses securely in their retaining clips and ensure that they cannot contact a potential chafing point.
^ Containers used for brake fluid must be kept absolutely clean.
^ Do not store brake fluid in unsealed containers, the fluid will absorb water which will lower the boiling point of the fluid.
^ Do not allow brake fluid to be contaminated with other fluids such as mineral oil and do not put brake fluid in a container which has previously been used for storing other fluids.
^ Do not reuse brake fluid which has been bled from the system.
^ Always use brake fluid or a suitable brake cleaning fluid to clean hydraulic components.
^ Unless stated otherwise, use only clean brake fluid to lubricate hydraulic seals and components.
^ Always fit blanking plugs to hoses, pipes or components immediately after disconnection.
^ Check thread compatibility of original equipment with replacement components.
^ Observe absolute cleanliness when working with hydraulic components.