Coupling & UncouplingCâu 5 / 60
After the kingpin has locked into the fifth wheel, how should you test that the coupling is secure?
a.Put the tractor in low gear and gently pull forward against the locked trailer brakes (tug test)
b.Rev the engine while in neutral
c.Bounce the cab up and down
d.Release all air and roll forward
Giải thích
You should perform a tug test by putting the tractor in low gear and gently pulling forward while the trailer brakes are locked. If the coupling is secure, the trailer will not separate. This confirms the kingpin is fully engaged before you crawl under to inspect.
Luyện miễn phí toàn bộ 60 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- What is the correct order for positioning the tractor before coupling to a trailer?
- Before backing under a trailer, the fifth wheel should be tilted how?
- When connecting the glad hands, what must you check to avoid a dangerous coupling mistake?
- After the tug test, why should you go under the trailer and look into the back of the fifth wheel?
- When should the locking jaws be closed around the kingpin?
- After the trailer is securely coupled and supported by the tractor, what should you do with the landing gear?
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