GMC 1976 ZEO 6083 Maintenance Manual page 263

5- 44 BRAKES
the high pressures which are developed when apply-
ing the brakes . In making up hydraulic brake pipes,
it is important that the proper flaring tool be used to
flare the ends of tubing for the compression cou-
plings . Unless the tubing is properly flared, the con-
nections will leak and the brakes will become
ineffective .
WARNING : NEVER USE COPPER TUBING BE-
CAUSE COPPER IS SUBJECT TO FATIGUE
CRACKING WHICH WOULD RESULT IN BRAKE
FAILURE .
Steel tubing must be double-lap flared at the ends
in order to produce a strong leakproof joint.
Special tools are available from tool companies
for making double-lap flares . Do not attempt to flare
steel tubing without proper tools. Figure 60 shows a
single and a double-lap flare, note the split in the
single-lap flare. The double-lap is well formed and
unbroken due to the reinforcement of the double
wall .
Refer to Figure 61 for brake line routing and
attachment .