equipment and get injured. A leak that drips on hot engine
parts may start a fire that could result in the loss of the
Every joint in a hydraulic system is a potential point
of leakage. This is why the number of connections in a
system must be kept to a minimum. Leaks often arise
from hoses that deteriorate and rupture under pressure.
Such a leak is usually first noticed when equipment has
remained idle for a period of time and hydraulic fluid is
found underneath. Figures 3-47 and 3-48 show the proper
procedures for repairing hoses with reusable fittings. You
can remove a medium- or high-pressure hose from its
fittings by unscrewing the nipple from the socket and
then the socket from the hose.
Here are some hints that will help reduce hose
leakage and maintenance:
Leave a little slack in the hose between
connections to allow for swelling when pressure is
applied. A taut hose is likely to pull out of its
Do not loop a hose unless the manufacturer
requires it. This causes unnecessary flexing of
the hose as pressure changes. Angled fittings
should be used instead of loops.
Do not twist a hose; twisting causes the hoses to
Use clamps or brackets to keep a hose away from
moving parts or to prevent chafing when the hose
Keep hoses away from hot surfaces, such as
manifold and exhaust systems. If you are unable to
do so, install a heat shield to protect the hose.
Route hoses so there are no sharp bends. This is
critical with high-pressure hoses.
Sometimes you can stop leaks at fittings by
tightening the hose connections. Tighten them only
enough to stop the leakage. If you cannot stop a leak by
tightening, secure the equipment and remove the
connection. Inspect the threaded and mating parts of the
connector. Look for cracks in the flared ends of the
tubing. If O rings are used, examine them for cuts or tears.
Any damaged or defective items should be replaced.
Figure 3-47.Replacing low-pressure hose on a reusable fitting.