Service technology — general recommendations (Honda Civic 6)

There are several methods for performing vehicle maintenance and repair procedures, to which the reader will find references in the text of this Manual. Following the suggested instructions will make the amateur mechanic's work more efficient, will allow the best organization and high-quality execution of various technical procedures, and will be the key to the full performance of all necessary work.

Fasteners

Fasteners are nuts, bolts, studs and screws used to connect two or more parts together. When working with fasteners, you must always remember some things. Almost any threaded fastener uses one or another type of locking and locking devices. These can be lock washers, lock nuts, lock flags or a special locking sealant for threads. All used fasteners must be absolutely clean and straight, with undamaged threads and unrounded corners of hexagonal heads for the key. It is a rule to replace damaged fasteners without fail. Special self-locking nuts with nylon or fiber inserts cannot be reused, since they lose their locking properties when loosened and must always be replaced during assembly.

"Stuck" fasteners should be treated with a special penetrating compound before loosening to make them easier to unscrew and to avoid damage. Many mechanics prefer to use turpentine for this purpose, which is conveniently applied from a special small canister with a long spout. After wetting the fastener with the penetrating compound, let the product soak the oxidized contact layer thoroughly for several minutes. Heavily rusted fasteners can be cut off with a chisel, sawed off with a hacksaw, or removed with a special nut splitter.



When a bolt head is sheared off or a stud is broken off on an assembly, the remaining threaded portion can be drilled out or extracted with a special extractor. Most auto repair shops can undertake this and other (for example, restoration of stripped threads in threaded holes), repair procedures.

Flat and lock washers must always be installed in their original positions during assembly. Damaged washers must be replaced with new ones. Between the lock washer and the soft metal surface (for example aluminum), when fastening thin sheet metal or plastic parts, always use flat washers.

Fastener dimensions

For many reasons, vehicle manufacturers are increasingly using metric fasteners. However, it is important to know the difference between the two (more versatile) fasteners and sometimes used SAE standard fasteners (or American). Despite the external similarity, the elements of these two types of fasteners are not interchangeable.

All bolts, both SAE and metric, are classified by diameter, thread pitch, and length. For example, an SAE 1/2-13x1 bolt is half an inch in diameter, has 13 threads per inch, and is 1 inch long. A metric M12-1.75x25 bolt has a diameter of 12 mm, a thread pitch of (distance between adjacent turns) 1.75 mm and 25 mm long. Both bolts are almost identical in appearance, but are not interchangeable.

In addition to the above features, both metric and SAE bolts can be identified visually by inspecting the head. For starters, the distance between the flats on a metric bolt head is measured in millimeters, while the American bolt is measured in inches (the same is true for nuts). As a result, an SAE standard wrench is not suitable for use with metric fasteners, and vice versa. In addition, most SAE standard bolts usually have radial notches on their heads that determine the maximum allowable tightening torque of the bolt (degree of strength). The greater the number of notches, the higher the permissible force (cars typically use bolts with strength classes from 0 to 5). The strength class of metric bolts is determined by a numerical code. The code numbers are usually cast, as on American fasteners, on the head of the bolt (automobiles typically use bolts of strength classes 8.8, 9.8, and 10.9).



Also, by the strength class marks, you can distinguish SAE nuts from metric ones. To identify the strength class of standard nuts, dot marks are used, stamped on one of the end surfaces of the nut, while the marking of metric nuts is made using, again, a digital code. The greater the number of dots, or the greater the value of the digital code, the higher the permissible tightening force of the nut.

Marking of the strength class of bolts (top - standard/SAE/USS, bottom - metric)

Strength class marking of standard hex nuts

Strength class 5

Strength class 8

Dimensions/strength class markings for standard (SAE and USS) bolts

Dimensions/Grade Markings for Metric Bolts

Metric Hex Nut Strength Class Markings

Strength class 9

Strength class 10

The ends of metric studs are also marked according to their strength class. Large studs are marked with a digital code, while smaller ones are marked with geometric shapes.

It should be noted that a significant portion of fasteners, especially those of strength class 0 to 2, are not marked at all. In this case, the only way to distinguish American fasteners from metric ones is to measure the thread pitch, or compare the threads with the threads of a uniquely identified element.

It should be remembered that only small fasteners fall under the SAE classification. Larger elements with non-metric threads are American Standard (USS) fasteners.



Since the fasteners are of the same geometric size (both standard and metric) may have different strength classes; when replacing bolts, nuts and studs, special attention should be paid to ensuring that the strength class of the newly installed elements matches the strength class of those removed.

Method and procedure for tightening threaded connections

Tightening of most threaded connections should be carried out with forces determined by the requirements of the Specifications given at the beginning of each Chapter of this Manual (the tightening force of a fastener should be understood as the torque applied to it). Overtightening can result in failure of the fastener, while undertightening can result in unreliable mating of the mating components. Bolts, screws and studs, depending on the material they are made of and the diameter of the threaded section, usually have strictly defined permissible tightening forces, many of which, as mentioned above, are listed in the Specifications at the beginning of each Chapter. Strictly adhere to the recommendations for tightening forces for the fasteners used on the vehicle. To tighten fasteners not listed in the Specifications, use the permissible torque chart below. The values in the table are oriented towards fasteners of strength classes 2 and 3 (higher-grade fasteners allow for greater tightening force), in addition, it is implied that dry tightening is carried out (with ungreased threads) fasteners screwed into steel or cast (not aluminum) detail.

Metric Thread Sizes

M6	9 - 12 Nm
M8	19 - 28 Nm
M10	38 - 54 Nm
M12	68 - 96 Nm
M14	109 - 154 Nm

Pipe thread sizes

1/8	7 - 10 Nm
1/4	17 - 24 Nm
3/8	30 - 44 Nm
1/2	34 - 47 Nm

SAE/USS Standard Thread Dimensions

1/4 - 20	9 - 12 Nm
5/16 - 18	17 - 24 Nm
5/16 - 24	19 - 27 Nm
3/8 - 16	30 - 43 Nm
3/8 - 24	37 - 51 Nm
7/16 - 24	55 - 74 Nm
7/16 - 20	55 - 81 Nm
1/2 - 13	75 - 108 Nm

A fastener located around the perimeter of a component (such as cylinder head bolts, oil pan bolts and various covers) must be loosened and tightened in a strictly defined order to avoid deformation of the part. The order of tightening and loosening such fasteners is given in the text of the relevant Chapters of the Manual, as well as in the accompanying illustrations. If a special order is not specified, then in order to avoid deformation of the component, the following instructions should be followed.

At the first stage, all bolts/nuts should be tightened by hand. Then, each of the fasteners is tightened one more full turn in turn, and the transition from one bolt/nut to another should be carried out in a diagonal order (criss-cross). Next, returning to the first element, repeat the procedure in the same order, tightening the fasteners another half turn. Continue the procedure, tightening each element now by a quarter turn at a time until they are all tightened to the required force. When loosening the fasteners, you should act in a similar manner, but in reverse order.

Disassembling the components

Disassembly of all components must be carried out in such a manner that during assembly each part could be installed in its original place and in the correct way. Try to remember the characteristic external features of the unit in the assembly, if necessary, make a landing marking of parts, the installation of which in place can be performed in an ambiguous way (for example, a grooved thrust washer on a shaft, etc.). It is a good idea to lay out the removed parts on a clean work surface in the order in which they were removed. It may also be helpful to make simple schematic sketches or take step-by-step photographs of the component being disassembled.

When releasing fasteners, try to mark their original position on the assembly. Often, installing fasteners and washers in their original place immediately after removing the corresponding part helps to avoid confusion during assembly. If this is not possible, all fasteners should be placed in a specially prepared box divided into sections and appropriately marked, or simply in separate marked boxes. This approach is especially useful when working with components consisting of many small parts, such as a carburetor, generator, valve mechanism, instrument panel or decorative trim elements.

When disconnecting electrical contacts and connectors, pay attention to marking the wires or harnesses using tape with a digital or letter code applied to it.

Gasket surfaces

On all vehicles, sealing gaskets are used to seal the junction of the mating surfaces of two or more parts and serve to prevent leaks of oils and other working fluids and maintain increased pressure/vacuum inside the assembly.

Often such gaskets are coated with a liquid or paste-like sealing compound before installation (sealant). Sometimes, over time or under the influence of elevated temperatures or pressure, the mating surfaces become so strongly pressed together that separating the parts becomes difficult. In many cases, successful separation of the components is assisted by tapping them from the outside along the perimeter of the joint with a soft-faced hammer. You can also use a regular hammer for this purpose, striking through a wooden or plastic spacer. Do not tap cast housings or components that are sensitive to shock. When this type of difficulty arises, always first check whether all fasteners have been removed.

Avoid levering the parts with a screwdriver or pry bar inserted into the joint area, as this can easily damage the mating surfaces, which will subsequently lead to the development of leaks. If it is impossible to avoid levering the assembly elements, use the handle of an old broom for this purpose, but remember that all the resulting splinters must be carefully removed from both the mating surfaces and from the internal cavities of the components of the unit being dismantled.

After separating the parts, their mating surfaces should be carefully cleaned using a scraper to remove traces of the old gasket material. Hardened fragments can be pre-softened using a rust converter or a special chemical composition. In this case, a piece of copper tube with a flattened and sharpened end can be used as a scraper. The remains of some gaskets can easily be removed using a copper brush, however, regardless of the method used, the mating surfaces must be completely clean and dry as a result of the treatment. If for any reason the mating surface is damaged, fill the defects with gasket sealant before assembling the unit. In most cases, non-hardening gasket sealant should be used (or not completely hardening) sealant.

Tips for removing hoses

Caution: If your vehicle is equipped with an air conditioning system, do not disconnect any hoses from the system components under any circumstances until the circuit has been discharged at a service station by an air conditioning specialist.

The precautions to be taken when removing hoses are very similar to those taken when dismantling gaskets. Avoid damaging the surfaces of the fittings and pipes onto which the ends of the hoses are pulled, as this may cause leaks to develop. The latter requirement applies especially to the procedure for removing radiator hoses. Due to various chemical reactions occurring in the cooling system, the rubber of the hoses often adheres to the surfaces of the fittings and pipes. To remove a hose, first loosen the clamp that secures it. Then use pliers to grasp the hose near the clamp and begin to rotate it on the fitting/connecting pipe to the right and left. Continue acting in this manner until the hose is completely free, then remove the hose from the fitting. A small amount of silicone or other grease introduced into the gap between the fitting and the hose will save effort. Before installing the hose, lubricate the inner surface adjacent to the end, as well as the outer surface of the fitting with a solution of soapy water or a small amount of silicone grease.

As a last resort, or in case of a clear need to replace the hose with a new one, the end of the hose put on the nipple can be cut with a knife and then separated from the surface of the nipple. In doing so, try not to damage the metal of the nipple/connecting pipe with the blade.

If the hose clamp is damaged, replace it with a new one. Twist-type clamps usually loosen over time, so regardless of their condition, it is better to replace them with more practical screw or worm-type clamps.

(Information obtained from this source: HONDABOOK)