basic automotive maintenance

KOLEJ YAYASAN SABAH

DIPLOMA TEKNOLOGI AUTOMOTIF

DTA 1024 : BASIC AUTOMOTIVE MAINTENANCE

TUGASAN KUMPULAN

TAJUK: TYRE WHEEL BEARING CHECK AND SERVICE

PENSYARAH

PN. SITI ZULAIHA BINTI ABDUL

AHLI KUMPULAN

RODNEY AVICTUS LAJUTA

941128-12-5051

RICKY ROGER

941024-12-5241

AG MOHD FECKRY BIN AG GHANI

920403-12-5417

Table Of Contents

1. Tyre 3

1.1. Definisi 3

1.2. Kod tayar 4

1.3. Penjagaan 6

1.4. Jenis 9

1.5. Fungsi 11

2. Wheel 12

2.1. Type13

2.2. Size and design 14

2.3. Wheel balancing 16

3. Bearing 18

3.1. Type18

3.2. Check method22

3.3. Replacement 24

Basic Automotive Maintenance – Tyre, Wheel, Bearing Check And Service |

Defisini TayarTayar adalah sebahagian roda yang diperbuat daripada getah. Tayar terdapat di banyak kenderaan seperti kereta, kapal terbang, basikal, motosikal dan sebagainya. Semasa memandu sesebuah kenderaan seperti kereta atau motorsikal, Tayar merupakan nyawa kedua anda selepas brek. Tayar adalah komponen yang paling penting bagi sesebuah kenderaan. Jika tayar sesebuah kenderaan rosak, ia boleh menyebabkan kemalangan sekaligus mengancam nyawa pemandu dan penumpang tanpa diduga.

Tayar merupakan bahagian yang penting untuk menghubungkan kenderaan dengan jalan raya. Namun begitu, ada beberapa perkara yang perlu diketahui pengguna sebelum membeli tayar kenderaan. Antaranya kod kapasiti berat dan kod kelajuan. Kedua-dua kod ini boleh kelihatan pada dinding tayar. Tetapi ramai di antara pengguna kenderaan terlepas pandang kod ini, mungkin kerana tiada pengetahuan. Sebenarnya kesesuaian tayar pada kenderaan berkait rapat pada kod-kod indeks ini. Kod-kod ini tidak boleh dipandang remeh kerana ianya menunjukkan berat yang mampu ditampung serta kelajuan yang dibenarkan mengikut spesifikasi setiap pembuatan tayar. Kod-kod ini adalah kod antarabangsa pada setiap pengilang tayar dan dianya tidak boleh diubah oleh pengilang tayar.


http://ms.wikipedia.org/wiki/Motosikal

http://ms.wikipedia.org/wiki/Basikal

http://ms.wikipedia.org/wiki/Kapal_terbang

http://ms.wikipedia.org/wiki/Kereta

http://ms.wikipedia.org/wiki/Getah

http://ms.wikipedia.org/wiki/Roda

Cara Membaca Kod Tayar

185 / 65 R13 91H

1. Maksud 185 adalah bacaan bagi kelebaran permukaan tayar dalam unit (mm).

2. Maksud 65 adalah bacaan bagi ketebalan tayar atau lebar permukaan sisi tayar dalam unit (%).

3. Maksud R13 adalah size rim yang sesuai dengan tayar tersebut.4. Maksud 91 adalah kapasiti beban yang boleh ditampung oleh tayar.5. Maksud H adalah kadar kelajuan yang maksimum bagi tayar tersebut.


INDEKS KELAJUAN TAYAR DAN INDEKS BEBAN TAYAR

Kapasiti Beban

Berat Maksimum

Kapasiti Beban

Berat Maksimum

84 500 92 63085 515 93 64586 530 94 67087 545 95 69088 560 96 71089 575 97 73090 600 98 75091 615 99 775

FORMULA MENGIRA BERAT YANG BOLEH DITAMPUNG


Cara Penjagaan Tayar1. Pastikan tayar yang dibeli mempunyai tanda ‘MS’ atau ‘DOT’ atau ‘E’.

(#C) 2. Jangan membeli tayar terpakai yang telah melepasi tanda paras amaran

botak (TWI) dan Tayar Toreh/ Korek. (#B) 3. Tukarlah tayar kenderaan anda apabila bunga tayar menyentuh tanda

paras amaran botak (Tread Wear Indicator (TWI)). (#A) 4. Periksa tayar anda setiap kali sebelum memulakan perjalanan dan

periksa tekanan angina tayar setiap seminggu sekali. 5. Lakukan penjajaran dan pengimbangan tayar setiap 10,000km perjalanan

atau lakukan dengan segera jika bermasalah contohnya stereng berasa gegar atau kenderaan lebih cenderung ke satu arah.

6. Lakukan putaran roda setiap 10,000km perjalanan atau mengikut buku panduan pengeluar kenderaan.

7. Sila hubungi kedai tayar yang bertauliah untuk pemeriksaan dan maklumat lanjut.

8. Jangan membawa lebih muatan daripada kemampuan tayar (rujuk pada carta indeks had muatan).

Tukar Kedudukan TayarTukar kedudukan tayar setiap 10,000km atau setiap tiga bulan bagi membolehkan tayar habis dengan sekata.


Tekanan Angin TayarJangan lupa periksa tekanan tayar sekurang-kurangnya dua kali sebulan. Tekanan tayar boleh dilihat pada pelekat yang lazimnya diletakkan di bahagian pintu pemandu sebagai rujukan. Jangan pam tayar lebih tinggi daripada had yang ditetapkan. Jangan biarkan tekanan angin tayar berada di bawah paras yang dicadangkan.

Mengikut tekanan angin yang dicadangkan tayar hadapan 210 dan belakang 190 kPa. lihat bacaan meter dekat pum angin. Tekan butang (+) atau (-).


http://4.bp.blogspot.com/-aOVNz0aG8IM/Tj9rsTNpb-I/AAAAAAAANHE/Ig46kJlkNr8/s1600/1.bmp


http://1.bp.blogspot.com/-sKYScZoOWt0/Tj9TMn8Z9TI/AAAAAAAANGM/aU0GKriXchA/s1600/1.bmp

Buat Alignment TayarTeknik dimana dua tayar di depan diselaraskan untuk sama rata masa memandu (maksudnya lurus kedepan) dan tayar belakang pula sama lurus dgn tayar depan supaya serentak semasa semasa memandu. Ada dua jenis iatu Castor dan Camber:1) castor yang memakai mesin tembak light antara kedua tayar supaya selari lepas itu laraskan nut untuk bagi selaraskan balik.

2) camber adalah teknik tambah screw di absorber untuk bagi pemberat kepada tayar.

Balacing

Balancing Keseimbangan yang tidak betul akan menyebabkan tayar berputar dengan goyangan yang disebabkan oleh daya putaran ("centrifugal force") yang tidak seimbang. Goyangan ini menyebabkan tayar haus secara tidak sekata dan mungkin juga muncul secara getaran juga.


(Getaran pada stereng ketika memandu adalah salah satu kesan dari masalah ini)


Jenis TayarTayar kenderaan moden boleh dibahagikan kepada dua jenis iaitu : -Tayar BertiubTayar jenis ini digunakan bersama – sama tiub yang sama saiznya dengan ayar. Tiub diletakkan di dalam tayar dan dipamkan udara melalui injap tuib untuk memenuhkan udara dalam tayar mengikut spesifikasi.

Tayar Tanpa Tiub (Tubeless)Kebanyakkan tayar yang digunkan pada masa kini adalah jenis tayar tanpa tiub. Udara di pam melalui injap yang dipasang pada rim.

Terdapat tiga jenis tayar yang lazim digunakan pada kenderaan bergantung kepada jenis lapisan badannyai. Tayar Lapisan Lintang


Lapisan tayar ini disusun menyerong dan bersilang antara satu dengan lain. Lapis-lapis silang ini bersudut 30’ hingga 40’. Tayar jenis ini biasanya lebih senyap, memberi keselesaan dan kelancaran ketika memandu. Tetapi tayar jenis ini mempunyai kekurangan ketika melalui selekoh atau membelok

ii. Tayar Jejarian

Lapisan tayar ini disusun melintang bersudutkan 90’ dengan garisan tengah bunga tayar. Binaan tayar jenis ini lebih kukuh dan mempunyai dinding sisi lebih lentur yang menjadikan tayar lebih lancar di pandu dengan kurangnya rintangan guling dan mempunyai tapak yang baik

iii. Tayar Lapisan Jejarian Dan Lintang

Lapisan tayar ini adalah gabungan antara lapisan jejarian dengan lintang. Tayar jenis ini lebih senyap, selesa, kukuh dan lancar semasa memandu


Fungsi Tayar

1. Tayar dapat bertindak sebagai kusyen udara di antara jalan dan roda dan menyerap getaran yang disebabkan oleh permukaan jalan yang tidak rata.

2. Tayar dapat memberikan cengkaman kepada permukaan jalanraya dan dengan itu kenderaan boleh di kawal dengan baik semasa membelok atau membrek.

3. Memberikan keselesaan kepada penumpang.4. Menampung berat keseluruhan kenderaan.


WheelsWheels must be strong enough to support the vehicle and withstand the forces caused by normal operation. At the same time, they must be as light as possible, to help keep un-sprung weight to a minimum.

Wheels can be made from cast aluminium alloy or magnesium alloy. Alloy wheels are popular because of their appearance and because they are lighter than similar steel wheels. Aluminium is a better conductor of heat, so alloy wheels can dissipate heat from brakes and tyres more effectively than steel ones. Most wheels have ventilation holes in the flange, so air can circulate to the brakes. Most passenger car wheels are of well, or drop-center design. This design allows for tyre removal and fitting. The removal and fitting of tyres should be carried out according to manufactures instructions.


Types of WheelsPassenger cars normally use rims which are of well based, or dropcentre design. The drop enter is used for mounting and demounting the tyre onto the rim. Wheels must be strong enough to carry the mass of the vehicle and withstand the forces that are generated during use. The wheel centre must accurately locate the wheel rim centrally on the axle. It must also provide the required distance from the centreline of the wheel, to the face of the mounting flange.

This is called offset. Offset is important because it brings the tyre centreline into close alignment with the larger inner hub bearing and reduces load on the stub axle. This allows the inside of the wheel centre to be shaped to provide space for the brake assembly, usually located inside the wheel. Ventilation slots allow air to circulate around the brakes. The rim must be accurately shaped and dimensioned and strong enough to support the tyre under the load of the vehicle and the forces generated by the motion of the vehicle. When inflated, the tyre is locked to the rim by tapering the bead seat towards the flange, or by safety ridges or humps, close to the flange. In the event of sudden deflation, or blow-out, safety ridges prevent the tyre moving down into the well. This helps maintain control of the vehicle while the brakes are applied. Well-based rims can also be used on heavy commercial vehicles for tubeless tyres.


Rim Sizes & DesignationsTo ensure correct fit between a tyre and rim, all manufacturers of wheels and tyres comply with standard dimensions, as recommended by automotive manufactures. The width of the rim is the distance across the rim flanges, at the bead seat. Its diameter is the distance across the centre of the rim from bead seat to bead seat.

The shape of well-based rims is provided by a letter code, such as J, K, JJ and KK. The width of the rim and the diameter is traditionally stated in inches. A rim designated 7 JJ by 14 would refer to a rim measuring 7 inches across the rim flanges and 14 inches in diameter from bead seat to bead seat, with the profile conforming to a JJ code.


The rim width and diameter can also be stated in millimetres. Metric rims are not interchangeable with Imperial rims. The tyre must be an exact fit on the rim, to fulfil a number of functions.

• It ensures that the narrow contact area between the beads of the tyre and the rim will seal the air in a tubeless tyre.

• It transfers all the forces between the tyre and the wheel, without slipping or chafing.

• It ensures the friction between the tyre and the rim prevents the tyre turning on the rim.


Dynamical Wheel/Tyre Balancing

Imbalance is an uneven distribution of mass about the tyre/wheel centre-line. Balancing is an essential process when fitting new tyres to wheels or after the tyre has been removed and then refitted to the rim. Most standard production tyres and wheels will, when built, have slight imbalances in their construction due to the nature of the manufacturing process. Balancing allows the technician to determine where these “heavy” spots are located and counteract the effect with balance weights.

An imbalance in a tyre/wheel assembly can usually be noticed as one of two things. Firstly an imbalanced front wheel will give a vibration that can be felt through the vehicle steering wheel. Secondly, an imbalance in the rear wheels will result in a vibration that can be “felt” through the vehicle body. As well as being uncomfortable this imbalance can have a detrimental effect on the vehicles handling and the wear of tyre thread, suspension linkage and shock absorbers.

Wheel balancers will check two kinds of balance, “static” (A) and “dynamic” (B). Static imbalance causes a wheel to shake up and down (wheel hop) as it spins, so static balance is achieved when both halves of the tyre wheel assembly weigh exactly the same.

Dynamic imbalance causes a tyre and wheel to shake back and forth or sideways as it spins (wheel shimming). Dynamic balance is achieved when the inner and outer sides of the wheel and tyre weigh the same.


Types Of Wheel Bearings When a wheel turns, it generates a certain amount of friction. The heavier the bearing on the wheel, the greater the resistance--thus the name "wheel bearing" for the component that reduces the friction between parts as the wheel spins. Relieving the resistance between the moving parts in a wheel reduces erosion and wear, prolonging the life of the wheel. The application of each type of bearing depends on the purpose of the wheel.

Ball Bearings

Easily the most common type of wheel bearing, the ball bearing is also the most versatile. Ball bearings have the ability to absorb both radial and thrust loads. Radial load is the amount of weight put on a wheel. The thrust load is the cornering pressure. Ball bearings can be found in wheels as small as those on roller skates to tires as large as those on automobiles.


Roller Bearings

Roller bearings are also commonly used wheel bearings; however, they do not have the versatility of ball bearings. They handle radial load well, but do not hold up under thrust. This makes them virtually unusable in wheels that have to corner with even moderate amounts of speed. However, they work well for wheels on items like handtrucks or grocery carts.


Tapered Roller Bearings

Tapered roller bearings are most often used in standard car and truck and wheels. The cone shape allows for the reduction of friction during cornering when thrust load is at its greatest. When a car turns, the wheels angle to varying degrees. Tapered roller bearings allow for this to keep shifting parts from grinding.


Precision Ball Bearings

Precision ball bearings are designed for high pressure and high performance use. They reduce friction to a minimum, do not generate as much heat and have a higher rotation speed than standard bearings. Precision ball bearings are used in world class racing cars and airplane landing wheels. They are specifically designed for intense radial and thrust loads.


Checking Of Wheel BearingYou can check your car's wheel bearings to see if they need to be repacked. Wheel bearings usually come in pairs of inner and outer bearings. They allow your wheels to turn freely over thousands of miles by cushioning the contact between the wheel and the spindle it sits on with frictionless bearings and lots of nice, gooey grease. This grease tends to pick up dust, dirt, and little particles of metal, even though the bearings are protected to some extent by the hub and the brake drum or disc.Usually, only the non-drive wheels (that is, the front wheels on rear-wheel drive vehicles and the rear wheels on front-wheel drive vehicles) have repackable wheel bearings. Vehicles with front-wheel drive have sealed front bearings, but some have packable rear ones. The bearings on four-wheel drive vehicles are quite complicated and should be repacked professionally.Before you check your bearings, consult your owner’s manual or dealership to find out whether the bearings on your vehicle are sealed. If they are, you can’t repack them. If you have drum brakes: It’s important to check the bearings

when you check your brakes to make sure that the grease hasn’t become fouled. If it has, the particles act abrasively to wear away the very connection the bearings are designed to protect, and the result is a noisy, grinding ride. In extreme cases, you could even lose the wheel! If the bearings look cruddy, either repack them yourself or get a professional to do it.

If you have disc brakes: You have to remove the caliper to get at the bearings. Although this task isn’t terribly difficult, certain aspects of the job can create problems for a beginner. Because your brake system can kill you if it isn’t assembled properly, you might want to do the job under supervision at an auto class.

If you just want to check your wheel bearings for wear without removing the wheels, do the following:1. Jack up your vehicle.

Support it on jack stands.2. Without getting under the vehicle, grasp each wheel at the

top and bottom and attempt to rock it.There should be minimal movement. Excessive play may indicate that the wheel bearing is worn and needs adjustment or replacement.


3. Put the gearshift in Neutral if you have an automatic transmission, or take your manual transmission out of gear.

4. Rotate the wheel.Listen for any unusual noise and feel for any roughness as it rotates, which may indicate that the bearing is damaged and needs to be replaced.

Shift back into Park (for an automatic transmission) or gear (for a manual transmission) before lowering the vehicle to the ground.


Replacing Of Wheel BearingTools

Jack and jack stands Wheel stopper Hammer Socket wrench set Plier Parts New bearing assembly Bearing grease

Instructions

1. Jack up the car. Use jack stands if possible, or blocks if not.2. Remove tires on the front. Remove brakes.3. Take out the grease cap (the center).4. Pull out Cotter Pin . Take nut out.5. Pull Rotor out. Take grease seal off of the back of the rotor. Pull out

inner and outer bearings.6. Using hammer and punch, knock out racings from the back of the

center of the rotor (very important to use new races, don't use the old ones). Clean out the center of the rotor with a clean rag.

7. Using the new bearings, replace the old ones, tapping them into place. It doesn't matter which one you install first.

8. Pack with grease when they are in place. Install new seal after the bearings are packed with grease.

9. Re-install the rotors into car; put brakes back on; replace tires.


http://www.ehow.com/how_2248505_replace-front-wheel-bearings-car.html

http://www.ehow.com/how_2248505_replace-front-wheel-bearings-car.html

10. Go for a test drive.

Tips & Warnings Make sure you get the nut tight on the bearings to "seat" them. Make sure the car is steady on the jack stands.


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