4300 Catalog
Assembly / Installation
Parker Hannifin Corporation
Tube Fittings Division
Columbus, Ohio
T25
Ferulok Troubleshooting Guide
Problems with bite type hydraulic fittings are most often traced
to faulty Pre-Set/Assembly procedure.
Fig. T35 – Tube not bottomed
Fig. T36 – Shallow bite
Fig. T37 – Over-set ferrule
Fig. T38 – Ferrule cocked on
tube
Fig. T39 – No bite
Table T23 – Ferulok fitting troubleshooting guide
Caution: Pre-set tools
such as the Ferulset and
Hyferset are preferred for
pre-setting ferrules prior
to final assembly. How-
ever, when an actual fitting
body is used to pre-set the
ferrule, that body should
be connected only to the
specific ferrule it was used
to pre-set.
Problem /
Probable Cause Remedy
Tube not
Check for the indentation on the tube
bottomed
end or compare the length from the end
of the tube to the front end of the ferrule
of a known good assembly to that of the
assembly in question. This assembly
should be scrapped. (Fig. T35)
Shallow bite
Inspect for turned up ridge of material.
A failure to achieve this ridge can
be traced either to the nut not being
tightened enough or the tube not being
bottomed against the stop which al-
lowed the tube to travel forward with the
ferrule. In some instances this assembly
may be re-worked. (Fig. T36)
Over-set ferrule
Too much pressure or more than 1 3/4
turns from finger tight were used to
pre-set ferrule, or the nut was severely
over-tightened in final assembly. This
assembly should be scrapped.
(Fig. T37)
Ferrule cocked
The ferrule may become cocked on
on tube
the tube when the tube end is not
properly lined up with the body. Gener-
ally, this condition is caused by faulty
tube bending. All bent tube assemblies
should drop into the fitting body prior
to make up. This assembly should be
scrapped. (Fig. T38)
No bite
If all of the prior checks have been
made and the ferrule still shows no sign
of biting the tube, it may be that the
tube is too hard. This assembly should
be scrapped. (Fig. T39)
Ferulok Assembly
Dimensions and pressures for reference only, subject to change.