WITH A WARM EN­GINE

Car Mechanics (UK) - - Servicing from Home -

Air fil­ters tend to be easy to re­place. Tak­ing care not to break any plas­tic hoses or mould­ings, de­tach the air pipes, un­clip or un­screw the top cover and lift-out the old el­e­ment. En­sure that the air-box is free from old leaves and road grot, prior to fit­ting a new pa­per el­e­ment and re­assem­bling the air-box assem­bly. Check the power steer­ing (PAS) fluid oil level. You might want to ex­tract a sam­ple to ver­ify its colour, but take care in case a suc­tion tool cross-con­tam­i­nates the reser­voir with any other fluid by ac­ci­dent. Dark brown, or black fluid could in­di­cate a po­ten­tial wear prob­lem in ei­ther the rack, or pump. Most PAS sys­tems use au­to­matic trans­mis­sion fluid, which tends to be red in colour, but there are sev­eral dif­fer­ent spec­i­fi­ca­tions, so make sure that you buy the cor­rect type. Some reservoirs con­tain fil­ters – clean them as di­rected in your work­shop man­ual, prior to top­ping up the sys­tem, if re­quired. There is nor­mally no need to change the fluid, but you may de­cide to do so any­way.

Brake fluid can be checked by look­ing through the translu­cent con­tainer. Nat­u­ral wear in the lin­ings causes the level to drop slightly, which is nor­mal. Fluid leaks, how­ever, are not. Check for any signs of leak­age be­neath the reser­voir and master cylin­der, as well as un­der the car. Also en­sure that any reser­voir fil­ters (see in­set pic) are clean.

Brake fluid re­quires chang­ing ev­ery two years. It is prefer­able to flush-through the sys­tem with new fluid, rather than suck­ing it out from the reser­voir and top­ping it up af­ter­wards. rec­om­mends the Gun­son Eez­i­bleed one-man brake bleed­ing kit, which uses air pres­sure from a tyre to pres­surise and top up the brak­ing sys­tem… …while you connect a tube to each of the car’s bleed nip­ples and ob­serve that the old fluid flows out of the sys­tem. Air bub­bles (as pictured) should not be vis­i­ble through the tube – if they ap­pear, wait un­til all of them are ex­pelled. Most cars have a bleed nip­ple on each brake caliper/cylin­der. Jack up and sup­port each side of the car and, from within the whee­larches, check the metal brake pipes for cor­ro­sion and the flex­i­ble pipes for de­te­ri­o­ra­tion. The pipe shown in the photo is danger­ously per­ished and, while it is not leak­ing, it could fail at any time. The pictured hose needs to be re­newed im­me­di­ately. While the wheels are off, en­sure that the brake pads’ fric­tion ma­te­rial has more than 3mm thick­ness re­main­ing – renew any fric­tion lin­ings in axle sets if you are un­sure that they will last un­til the next ser­vice. Check that the metal brake discs are free of cracks. The in­set pic shows a danger­ously-worn pad be­side a new one. If your car has rear drum brakes, you’ll have to re­move the outer drum to in­spect the lin­ings. They tend to be held on with ei­ther small re­tain­ing screws, or a large cen­tral re­tain­ing Ny­loc nut, which must al­ways be re­placed. On some mod­els, the bear­ing might come out as the drum is with­drawn. Do not drop greasy bear­ing parts on the floor – grit will shorten their work­ing lives. En­sure there is plenty of lin­ing re­main­ing on the brake shoes. Fluid leaks tend to orig­i­nate from a failed seal within the hy­draulic cylin­der. If the shoes have be­come wet with fluid, they must be re­newed in axle sets along with the faulty cylin­der, so that there is no risk of a brake im­bal­ance.

Check for frayed hand­brake ca­bles and en­sure that they are greased, if re­quired. Some mod­els re­quire man­ual ad­just­ment of the hand­brake to re­duce lever travel, which can be done by rais­ing both sides of the car and turn­ing an ad­juster (pictured) un­til the wheels lock, then back-off un­til the wheel(s) spin freely. Some cars re­quire that the ca­ble is ad­justed, so check what is ap­pro­pri­ate for your model. Diesel en­gines need to have their fuel fil­ter hous­ings drained an­nu­ally, which re­moves any wa­ter that could dam­age the high-pres­sure cir­cuit. On this car, a pipe is con­nected to the drain out­let (see in­set pic), which is un­screwed to al­low the fuel to flow into a re­cep­ta­cle. The top vent screw is opened too (as shown) to aid the flow. Fuel in­jec­tion spe­cial­ists rec­om­mend that diesel fuel fil­ters are re­placed an­nu­ally. Start by drain­ing the fil­ter hous­ing (see Step 48) and re­mov­ing the top cover; this can be held in place with screws, or else the top might un­wind. Dis­con­nect the fuel pipes and plug, or cover them to en­sure no con­tam­i­nants can en­ter the high-pres­sure sys­tem. De­tach any elec­tri­cal con­nec­tors, too. With the fil­ter can­is­ter re­moved, en­sure that the hous­ing is clean, with no metal con­tam­i­na­tion in­side (see in­set pic), then fol­low Steps 48 & 49. Renew the fil­ter and fit a new seal, but lu­bri­cate it with clean diesel (not en­gine oil), prior to re­fit­ting the cap and re­con­nect­ing the fuel lines and elec­tri­cal con­nec­tions. You will need to prime the diesel sys­tem so the en­gine will start; some mod­els do this au­to­mat­i­cally. Cor­rect bleed­ing is crit­i­cal – cer­tain cars (such as Volvo’s five-cylin­der units) suf­fer from dam­aged pumps if not bled prop­erly – and check if di­ag­nos­tic equip­ment is needed. Here, the pipe is con­nected to the top screw and the bot­tom drain is tight­ened, then the primer bulb is squeezed to re­fill the cham­ber. Pump­ing stops when air bub­bles cease to be drawn into the tube. Run the en­gine at a fast idle af­ter bleed­ing to purge the sys­tem of any re­main­ing air. Petrol en­gines tend to have dif­fer­ent re­quire­ments; most fil­ters are si­t­u­ated be­neath the car, as pictured. Con­sult your work­shop man­ual on how to de­pres­surise the fuel sys­tem. This petrol car has a bleed screw fit­ted to its fuel rail (see in­set pic), but un­screw­ing it will pour fuel over the hot en­gine and cre­ate a fire risk.

If petrol fil­ter re­place­ment has been ne­glected, the unions may be stub­born to undo. Be pre­pared for some fuel to drain from the fil­ter and pipes as the unit is with­drawn. When fit­ting a re­place­ment, make sure that the ar­row on the body points in the di­rec­tion of fuel flow, which tends to be from the tank to the en­gine (see in­set pic).

Hy­draulic clutch sys­tems usu­ally utilise the brake fluid from the main reser­voir and com­pen­sate au­to­mat­i­cally for clutch disc wear. Some ca­ble-op­er­ated clutches in­cor­po­rate auto-ad­justers, but should ad­just­ment nuts be fit­ted to your car (see in­set pic), fol­low the work­shop man­ual in­struc­tions to ei­ther re­duce the clutch pedal height and in­crease free play, or negate clutch slip.

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