OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
For each cause the 5 why analysis is used to explore the cause and effect relationships underlying a particular
problem and developing the counter measures. The primary goal of 5 why analysis technique is to determine the
root cause of a brake spongy defect by asking question why for 5 times and find the answers for these questions
which will be helpful in developing counter measures. Due to space limitations 5 why analysis and identification
of countermeasures for the cuases due to ‘Man’ are explained in the paper.
Fig. 6 Cause and Effect Diagram for Brake Spongy
2.1 Five Why Analysis – Brake Spongy Defect due to Man
It explains how the brake spongy defect occur from worker during assembling the brake system components
using 5 Why Analysis, Accordingly 5 why possible questions were identified as given below.
(i) Why – there is improper tightening of Brake tube
The tightening defects in brake tube causes due to improper apply of torque, cross thread and poor seating of
double flare, which are described hereunder.
Torque: the torque should be in correct range while tightening brake tube if the worker applied torque is less then
there will be gap between the double flare and tubing seat shown in Fig. 7, due to this there will be leakage of
vacuum pressure which causes pre-vacuum error. Torque should be between 9.5 Nm to 22.5 Nm and target value
is 16 Nm.
Fig. 7 Brake Tube
338