Hyundai r35z-7 Workshop Manual page 205

6)
BOOM MAKES A SQUEAKING NOISE WHEN BOOM IS OPERATED
YES
Is boom foot pin
greased
sufficiently?
NO
5-22
Cause Remedy
Frictional noise
occurs between
the sliding faces
of boom
cylinder's oil
seal and boom
proper.
Frictional
noise will
disappear if
they are kept
used.
Boom foot pin Supply grease
has run out of to it.
grease.
If seizure is in
an initial stage,
supply sufficient
grease.
If seizure is in
a grown state,
correct it by
paper lapping
or with an oil
stone.