General requirements to car repairs. Nissan Almera (from 1995 to 1999 release)
Service of Nissan Almera from 1995 to 2000 in N15 body
1. General information
2. General requirements to car repairs
3. Operation and maintenance of the car
4. Petrol engines
5. Diesel engines
6. Transmission
7. Running gear
8. Steering
9. Brake system
10. Electric equipment
11. Body
12. Appendices
13. Schemes of electric equipment
 









2-obshhie-trebovaniya-k-remontu-avtomobilya.html

2. General requirements to car repairs

The main part of malfunctions of mechanical knots and units arises owing to processes of friction, deformation of elements, aging of material of details, etc. These and other processes vpenut for themselves wear and damage of details. Process of wear can be divided into three periods: to extra earnings, normal and emergency wear. In process extra earnings there is an intensive wear of the rubbing details, as a result of microroughness of the interfaced surfaces decrease, the area of contact grows, specific loadings decrease, the speed of wear is slowed down and there comes the period of normal wear. It is characterized by rather small growth rate of a gap in interface, however on reaching a certain gap wear speed sharply increases that testifies to the beginning of the period of emergency wear. Operation of the unit with emergency wear leads to breakages. It is in use very important to subject knot to repair before emergency wear, at the same time costs of repair will be much lower, than at repair of the unit with emergency wear.
Before making decision on repair it is necessary to diagnose a condition of units. As a rule, diagnosing is conducted on indirect signs, such as the increased noise, vibration, an oil consumption, break of crankcase gases, etc. For better diagnostics the unit needs to be disassembled, details to wash out, examine and take necessary measurements. By results of survey and measurements the decision on continuation of operation or on need of repair is made. At the same time it is necessary to be guided by the following reasons: if the actual sizes of details are in borders of fields of the admissions allowed by the this manual, then continuation of operation of the unit without repair is possible; if the sizes went beyond admissible fields of admissions, then repair is required. The expansions of fields of admissions given in the present manual should be understood as a possibility of use of a residual resource of knot without restoration of interfaces. In case of repair of the unit at restoration of interfaces expansion of fields of admissions over nominal is not allowed. The technology of repair can be divided into four main stages of works:
— dismantling and sink;
— control and sorting;
— actually repair: restoration micro and macrogeometry of surfaces of details and physicomechanical properties;
— assembly with preliminary control of the details arriving on assembly.
Dismantling and washing operations conduct in several stages: an external wash of the unit, preliminary dismantling of the unit on knots, a sink of knots, dismantling of knots on a detail, a sink and cleaning of details. All details before control and sorting should be cleared carefully of dirt and a deposit, to degrease, wash out and dry up.
Oil channels and openings in details should be cleaned, washed out under pressure and to blow compressed air. Details from aluminum and zinc alloys are not allowed to be washed out in the alkaline solutions applied to a sink of steel and pig-iron details as aluminum and zinc are dissolved in alkalis.
In the course of control of details chips, cracks, dents, sinks and other damages find external survey. At responsible details existence of cracks is checked by means of the defectoscope. The sizes of details need to be controlled in places of the greatest wear. Teeths of gear wheels wear out unevenly therefore at their control it is necessary to measure not less than three teeths located approximately at an angle 120 °. In view of need to guarantee operation of tooth gearings during all between-repairs run chips on teeths and a vykrashivaniye of fatigue character on a working surface of teeths are not allowed. Assembly units, such as a rod with a cover, the block of cylinders with covers of radical bearings, gear wheels of the transmission and the main transfer, it is impossible to razukomplektovyvat. Other assembly units can be razukomplektovyvat; but if the decision on continuation of operation of the interfaced elements without repair is made, then them it is inexpedient to razukomplektovyvat. In all cases of repair of details welding and a naplavka the welded seam should not have slag inclusions, not boiled thoroughly sites, undercuts and other defects. After welding it is necessary to smooth out a seam and to eliminate metal flows that they did not prevent installation of the interfaced details.
Carving openings with the worn-out or damaged carving restore cutting of a carving of the increased repair size, tea leaves of openings with the subsequent cutting of a carving of the nominal size, installation of spiral carving inserts. Application of carving inserts is more preferable for reasons of quality of restoration and labor costs. The insert represents the spiral reminding the spring made of a wire of rhombic section. On one end of a spiral will bend a technological lead by means of which the insert is wrapped in previously prepared opening. Technological process of repair of a carving opening by means of a spiral insert includes the following operations:
— drilling of a defective opening to the repair size;
— cutting in it of the carving corresponding to the size of a spiral insert;
— a vvorachivaniye of a spiral insert and an oblamyvaniye of a technological lead on a notch.
In tab. 1.5 the sizes of openings and a carving under the spiral inserts applied at repair of automobile details are specified.
For repair of carving openings spiral inserts special packages in which inserts, drills, special taps, keys for a vvorachivaniye of inserts, small beards for cutting of a technological lead are included are issued.
The details given on assembly have to be pure and dry. Threaded connections should not have damages. Disposable самоконтрящиеся carving fasteners at assembly have to be replaced by new. In case of impossibility to apply new самоконтрящиеся details when using old it is necessary to stop in addition them from an otvorachivaniye.
At assembly surely replace new laying and cuffs. Oil the rubbing surfaces of details at assembly pure. At installation of rubber cuffs grease their working surfaces in order to avoid damage at installation. At installation of cuffs with the metal case apply in a groove for installation of a cuff a thin film of sealant.
Carry out assembly of knots and units according to the present manual.

Table 1.5 the Sizes of an opening and carving under repair spiral inserts
Nominal carving
Diameter of a drill, mm
Carving under a spiral insert
M5 x 0,8
5,2
M6 x 0,8
MB x 1,0
7
M8kh 1,0
M8kh 1,25
8,7
M10kh 1,25
MYuh 1,5
10,5
M12kh 1,5
M11 x 1,0
12
M13kh 1,0
M12kh 1,75
12,2
M14kh 1,75
M12kh 1,5
12,5
M14kh 1,5
M14kh 1,25
14,7
M16kh 1,25
M14kh 1,5
14,7
M16kh 1,5
M16kh 1,5
16,5
M18kh 1,5
M18 x 1,5
18,1
M20 x 1,5

By means of the measuring tool check the sizes of the interfaced details before assembly. At assembly of the details having mobile landing in interface their free relative movement without jammings has to be provided. Plugs, rings of ball and roller bearings establish by means of mandrels. At a press fitting of bearings the effort should not be transmitted through balls or rollers. The tool for a press fitting has to rest against the pressed ring. The effort of a press fitting has to be directed parallel to a bearing axis in order to avoid a distortion of rings. If under the terms of assembly installation of responsible details is carried out by blow of the hammer, it is necessary to apply mandrels and hammers from soft metal, plastic, rubber, and also the device for a press fitting of details.
Splines have to be densely put in shponochny grooves of shaft by means of the hammer or a mandrel from soft metal. The side play of splines in grooves of shaft is not allowed.
Hairpins have to be wrapped in carving openings densely, without side play. Details have to be put on hairpins freely. Podgibaniye of hairpins at installation of details on them is not allowed, fastening of knot or detail several nuts or bolts has to be carried out evenly on perimeter — at first previously, and then is final. All identical nuts or bolts of one connection have to be tightened by one moment.
In all cases provided by the management it is necessary to apply the dynamometer keys allowing to regulate the inhaling moment. The moments of an inhaling of threaded connections if they are specially not stipulated in specifications, are defined depending on diameter of a carving according to tab. 1.6.
When fastening details bolts have to act from nuts not less than on two-three rounds of a carving, except especially stipulated cases.

Table 1.6 the Recommended moments of an inhaling of threaded connections
Diameter of a carving, mm
Moment of an inhaling, kgf-m
6
0,6-0,9
8
1,4-1,7
10
3,0-3,5
12
5,5-6,0
14
8,0-9,0
16
12-14
18
16-19
20
23-27

Forelocks should not act from cuts of nuts. The ends of forelocks have to be divorced and unbent — one on a bolt, and another on a nut.
To blow tubes of fuel-supply lines and the drive of brakes before assembly compressed air.

"previous page
1. General information
following page"
3. Operation and maintenance of the car







7f435ca2