Chevrolet 70 1969 Series, Руководство по ремонту

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FRAME 2-8
Figure 8— Plug Patterns of Strap Reinforcements
type, should not be attached to the flanges except
in the case where a mounting bracket or crossm em ­
ber holes are already through the frame flange.
3. Plug welds may be used in a staggered 8 to
10 inch pattern when attaching reinforcements to
the web section (fig. 8).
4. Strap reinforcements may be plug welded
at 6 to 8 inch intervals to the flanges in some cases;
however, as pointed out, this is for section modulus
increase and should only be attempted by highly
qualified specialists.
The termination of reinforcements is very
important. Reinforcement ends must be scarfed or
stress relieved to prevent localized stress con­
centration. This scarfing should not be greater
than 45 (fig. 6). It should also be strongly empha­
sized that in cases where several reinforcements
are used, the ends of the reinforcements must
overlap and be staggered so that the reinforcement
ends overlap by eight to ten inches.
— CAUTION —
GENERAL RULES
Listed below are general rules which apply to
frame repair and reinforcements. Most of these
rules are discussed earlier in this section; how­
ever, the importance of adhering to them cannot
be overemphasized.
1. Always identify the material of base rail.
2. Frame straightening or repair must be at­
tempted only by highly qualified specialists.
3. Always attempt to identify the cause of
failure.
4. Fifth wheel, body, and accessory mountings
should not be made through frame flanges. (See
"Body Builder's Book".)
5. Do not drill holes in the lower flanges.
6. Use only proper electrodes as specifiedfor
base rail material when welding is necessary.
7. Do not use oxyacetylene welding equipment
on frames.
8. Do not weld reinforcements across the
frame flanges.
9. Do not weld within 1/2 inch of the edge of
a frame flange.
10. Remove all notches or weld build-ups
from flange edge when repairing a broken frame.
11. Do not weld cast brackets to frame.
12. Do not weld the flanges of cracked rein­
forcements and base rails together.
13. Do not patch cracks. Reinforce the area.
14. Reinforcement should be of the same or
better material than base rail.
15. Always scarf reinforcement ends to pro­
vide adequate stress relief.
16. Always stagger ends of reinforcements by
a minimum of eight inches apart.
17. The Zone Office or Factory should be con­
tacted when repairs are necessary on heat treated
side rails.
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L