Fasteners. Isuzu Isuzu T-Series (Truck Line C) 2002

For 1990-2009 cars only

Makes 🢒 Isuzu 🢒 2002 🢒 Isuzu T-Series (Truck Line C) 🢒 General Information 🢒 General Information 🢒 Fasteners

Fasteners Prevailing Torque Fasteners

Table 1:	Metric Fasteners (Prevailing Torque)
Table 2:	English Fasteners (Prevailing Torque)

Engineers design prevailing torque nuts in order to develop an interference between the nut and bolt threads. Usually the interference is caused by distorting the top of a metal nut (1, 2) or by a nylon patch on the threads in the middle of the hex flat (3). A nylon insert between the nut and bolt threads also may cause the interference (4, 5).

Engineers design prevailing torque bolts in order to develop an interference between the bolt and nut threads, or the threads of a tapped hole. The interference is caused by distorting some of the threads using one of the following methods:

•	A nylon patch (8)

•	Adhesive (6)

•	A deformed thread profile (7)

•	An out of round thread area (9)

Recommendations for Reuse

Perform the following steps in order to reuse clean, non-rusted, prevailing torque nuts:

Clean dirt and other foreign material off of the nuts and bolts.
Inspect the nuts or bolts for the following conditions. If any of the following conditions exist, use a new prevailing torque fastener:

•

Cracks

•

Rust

•

Damage

•	Elongation

•	Signs of abuse

•	Signs of overtightening

Assemble the parts.
Hand start the nuts or bolts.
Ensure that the fastener develops proper torque before the fastener seats. Refer to the Torque Table. If the proper torque does not develop, use a new prevailing torque fastener.
Tighten the fastener to the torque specified in the appropriate fastener tightening specification.

Metric Fasteners (Prevailing Torque)

Fastener Type	Specification
Fastener Type	Metric	English
Nuts/Metal Bolts
6	0.4 N·m	4 lb in
6.3	0.4 N·m	4 lb in
8	0.8 N·m	7 lb in
10	1.4 N·m	12 lb in
12	2.2 N·m	19 lb in
14	3.0 N·m	27 lb in
16	4.2 N·m	37 lb in
Adhesive or Nylon Coated Bolts
6	0.4 N·m	4 lb in
6.3	0.4 N·m	4 lb in
8	0.6 N·m	5 lb in
10	1.2 N·m	11 lb in
12	1.6 N·m	14 lb in
14	2.4 N·m	21 lb in
16	3.4 N·m	30 lb in

English Fasteners (Prevailing Torque)

Fastener Type/Torque Units	Specification
Fastener Type/Torque Units	Metric	English
Nuts/Metal Bolts
0.250	0.4 N·m	4 lb in
0.312	0.6 N·m	5 lb in
0.375	1.4 N·m	12 lb in
0.437	1.8 N·m	16 lb in
0.500	2.4 N·m	21 lb in
0.562	3.2 N·m	28 lb in
0.625	4.2 N·m	37 lb in
Adhesive or Nylon Coated Bolts
0.250	0.4 N·m	4 lb in
0.312	0.6 N·m	5 lb in
0.375	1.0 N·m	9 lb in
0.437	1.4 N·m	12 lb in
0.500	1.8 N·m	16 lb in
0.562	2.6 N·m	23 lb in
0.625	3.4 N·m	30 lb in

Fasteners Strength Identification

Fastener Strength Identification


(1)	English Bolt, Grade 2 (Strength Class)
(2)	English Bolt, Grade 5 (Strength Class)
(3)	English Bolt, Grade 7 (Strength Class)
(4)	English Bolt, Grade 8 (Strength Class)
(5)	Metric Nut, Strength Class 9
(6)	Metric Bolts, Strength Class Increases as Numbers Increase

Notice: The designation of the standard fasteners used on this vehicle are of coarse screw thread up to M8 and fine screw thread beyond M10. The designation to pitch relations are somewhat different between coarse screw thread and fine screw thread. Therefore, when replacing fasteners, the pitch should be confirmed carefully even if the replacement fastener is the same metric fastener.

The most common metric fastener strength property classes are 9.8 and 10.9. The class identification number is embossed on the head of each bolt (6). Some metric nuts are marked with single digit strength identification numbers on the nut face.

English strength classes range from 2 (low strength) to 8 (high strength). A grade-2 bolt has no lines embossed on the bolt head (1). One radial line is embossed on the bolt head for each strength grade above 2. That is, a bolt with one embossed line indicates grade-3. Two embossed lines indicate grade-4. Six embossed lines signify grade-8, the highest-grade bolt (4).

Correct replacement bolts and nuts are available through American Isuzu Parts Distributor Network (AIPDN). Many metric fasteners available in the after-market parts channels are designed to foreign metric standards, and may have a different thread pitch. Isuzu products use metric fasteners designed to new, international standards. Some non-domestic bolt and nut suppliers may not yet use the international standards.

Metric Coarse Screw Threads				Metric Fine Screw Threads
Thread	Pitch	Thread	Pitch	Thread	Pitch	Thread	Pitch
M39	4	M8	1.25	M39x3	3	M20x1.5	1.5
M36	4	M7	1	M36x3	3	M18.1.5	1.5
M33	3.5	M6	1	M33x2	2	M16x1.5	1.5
M30	3.5	M5x0.8	0.8	M30x2	2	M14x1.5	1.5
M27	3	M4x0.7	0.75	M27x2	2	M12x1.25	1.25
M24	3	M4x0.7	0.7	M24x2	2	M10x1.25	1.25
M22	2.5	M3.5	0.6	M22x1.5	1.5	M8x1	1
M20	2.5	M3x0.5	0.5	--	--	--	--
M18	2.5	M2.5	0.45	--	--	--	--
M16	2	M2.2	0.45	--	--	--	--
M14	2	M2	0.4	--	--	--	--
M12	1.75	M1.6	0.35	--	--	--	--
M10	1.5	--	--	--	--	--	--

Fasteners Metric Fasteners

Current model Isuzu vehicles are dimensioned primarily in the metric system. Many fasteners are metric and are very close in dimension to fasteners in the inch system. Replace the fasteners using the following identical specifications:

•	The nominal diameter

•	The thread pitch

•	The strength

Most stock metric fasteners have numbers indicating the strength of the material in the fastener. "Beauty" bolts, such as exposed bumper bolts have no strength indicator. Identify metric cross-recess screws by a Posidriv® or Type 1A marking. Use a Type 1A cross-recess screwdriver in order to fasten or unfasten metric cross-recess screws. If a Type 1A cross-recess screwdriver is not available, use a Phillips head screwdriver.

Isuzu Engineering Standards and other North American industries use a portion of the standard metric fastener sizes defined by the International Standards Organization (ISO). Now the total number of fastener sizes in use is lower, and the overall strength quality of each thread size is higher.

For example, the metric M6.0 x 1 screw replaces the English 1/4-20 and 1/4-28 screws, which have nearly the same diameter. The thread pitch, 25.4 threads per inch, is between coarse and fine thread pitches in English. Metric and English thread notations differ slightly. The thread major diameter of a 1/4-20 bolt is 1/4-inch, and the bolt has 20 threads per inch. The thread major diameter of a 6.0 x 1 bolt is 6.0 mm, and the distance between threads is 1 mm.