Brakes Work Example 11

WorkKey Level: 4
NATEF Automotive Tasks: V.D.2

You are testing the vacuum supply to a power brake booster assembly. The spec, according to the manual, is 17 inches of vacuum at an engine idle speed of 850 RPM, with all accessories turned off.  There is an allowable tolerance of +2 inches. Your gauge is reading 15.5 inches with all conditions met.  Your gauge reading is:

a.  Out of tolerance and needs further diagnosis

b.  Out of tolerance but it doesn’t matter

c.  In tolerance and is acceptable

d.  In tolerance but needs to be further diagnosed

Solution:

An acceptable reading is 17 inches +2 inches.
17" – 2" = 15"
17" + 2" = 19"
The acceptable range is 15" < x < 19"

Option C is the correct answer, since your gauge is reading 15.5 inches which falls within the acceptable range.