If the axle is bent, out-of-round, or shows signs
of wear, replace it. Check for worn roll pin holes. If these are damaged
or worn, replace the axle.
Bushings are designed to wear out sooner than the mating
parts. They are made of softer material and are expendable. It is recommended
that anytime the jack is torn down to a point where the bushings are
accessible, they be replaced. This will ensure longer life of the jack
and will reduce the amount of downtime. Bushings are very inexpensive
and it is cost effective to change them regularly.
If bushings are cracked, broken, egg shaped or worn
more than 1/16" from the original size replace them.
Remember: If the jack is already disassembled, replace
all accessible bushings.
Tip: Coating axles and bushings with anti-seize compound
before installation makes maintenance easier.
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Rollers and Load Roller Brackets
Load roller - Load rollers should not have flat spots
or large pieces of metal imbedded in them (i.e. tacks, nails or metal
shavings). Any chips in the wheel that keep it from rolling smoothly
indicate the need for replacement. If the wheel has cracks, loose tread,
or does not turn freely, replace both wheels. Always change the wheels
in pairs to reduce uneven wear. New load rollers have an outside diameter
of 3"(L-50), 2"(L-50 mini), and 1 3/4" (L-50 CHEP). If
the diameter is worn more than 1/4" from its normal size, replacement
Load roller brackets - Inspect the brackets for cracks
or wear from prolonged rubbing on the floor. Check for out-of-round
axle holes and inspect the bushings closely (see Bushing Inspection).
If any of the above conditions exist, replace the brackets.
Tip: We recommend servicing one load roller assembly at a time, using
the other assembly as a reference.
Load roller - Remove the nut and washer from the axle
bolt. Slide the axle bolt out of the brackets and remove the load roller.
Remove the load roller axle sleeve from the load roller. (10 minutes).
Load roller bracket - Remove the load roller. With
a pin punch and hammer, drive out the roll pin that fastens the pivot
axle to the frame, then drive the pivot axle out of the frame, exit
roller, and brackets. Pull the push rod away from the frame and slide
the brackets off the push rod. (15 minutes)
Load roller brackets - Slide the brackets onto the
push rod and insert the pivot axle through the frame, brackets and the
exit roller (the 4-way does not use an exit roller). Secure the pivot
axle to the frame with its roll pin and install the load roller. (15
Load roller - Insert the load roller axle sleeve into
the load roller and place the load roller between the brackets. Install
the axle bolt through the brackets and load roller. The use of washers
differs from one style to the other. Use the diagrams below or the other
load roller bracket assembly on the jack as a reference. Secure the
axle bolt with its nut. (10 minutes)
Wheels and Axle
Steer wheels should not have flat spots or large pieces of metal imbedded
in them (i.e. tacks, nails or metal shavings). Chips in the wheel, which
keep it from rolling smoothly, indicate the need for replacement. Steer
wheels should turn freely. They should not rub the bottom of the traverse.
If they do, check for the correct installation of the snap ring under
the traverse. If the wheel is worn more than 1/4" from the normal
outside diameter, replacement is necessary.
Steer wheels - Turn the jack onto its side and then
remove the hubcap. Remove the snap ring for the newer style, or the
roll pin for the older style, that fastens the steer wheels to the axle.
Steer wheel axle - Turn the jack onto its side and
remove the steer wheels. Drive out the roll pin that fastens the axle
to the stem of the hydraulic unit and slide the axle out. (15 minutes)
Steer wheel axle - Slide the axle into the stem of
the hydraulic unit and fasten with its roll pin. Install the steer wheels.
Steer wheels - Slide the wheels onto the axle and secure
with its fasteners (snap rings for the newer style or roll pins for
the older style). (10 minutes)
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There are few things that can be wrong with the traverse. Wear can occur
on the bearing shoulder or where the shoulder bolts attach to the lifting
link. If these areas are egg-shaped or out-of-round, replace the traverse.
Turn the jack onto its side and remove the steer wheel assembly (see
Steer Wheels and Axle). Remove the snap ring under the traverse and
turn the jack upright. Be careful lowering the stem of the hydraulic
unit onto the ground. Pump the jack up to gain access to and remove
the bolt that fastens the lift ram to the frame. Pull the hydraulic
unit away from the frame and out of the traverse. Remove the shoulder
bolts and the traverse. (25 minutes)
Attach the traverse to the lifting link with its shoulder bolts. Slide
the hydraulic unit into the traverse, with the washers and lower thrust
bearing already in position on the stem of the hydraulic unit. Position
the lift ram and ball under the A-Frame. Tighten the bolt onto the ram
to secure the ram in place. Turn the jack onto its side, and install
the snap ring onto the stem of the hydraulic unit to hold the traverse
in place. Install the steer wheel assembly (see Steer Wheels and Axle).
When inspecting the push rods, look for broken or cracked welds, bends,
missing roll pins and worn bushings. It is best to mark the position
of the eyebolt and nut in relation to the push rod to ensure proper
adjustment during installation.
Turn the jack over so that the undercarriage is facing up. Remove the
load roller brackets (see Load Roller Brackets). Loosen the nut on the
push rod and then the push rod can be threaded off of the eyebolt. The
eyebolt can be removed with the push rod by using a hammer and pin punch
to drive the roll pin out of the pin that fastens the eyebolt to the
lifting link. Remove the pin and the push rod. The eye bolt can then
be removed from the jack. (20 minutes)
Turn the jack over so that the undercarriage is facing up. Fasten the
eyebolt to the lifting link with its pin and secure the pin with its
roll pins. Thread the nut onto the eyebolt with enough room to thread
the push rod on, also. Thread the push rod onto the eyebolt until it
approximately matches the other push rod. Assemble the load roller brackets
and the load roller onto the push rod. Line up the pivot axle hole on
the brackets to the axle hole on the frame. Slide the pivot axle through
the frame, brackets and exit roller (if it has one). Secure the pivot
axle to the frame with its roll pin. Tighten the nut on the eyebolt
against the push rod. (Note: The nut on the eyebolt is primarily a marker
for proper adjustment. It also keeps the eyebolt or push rod from spinning
out of adjustment when working on the load roller brackets or the lifting
link.) It is easiest to adjust the push rod correctly if both push rod
and bracket assemblies are in a fully lowered position before installing
the pivot axle.
To ensure that the push rods are adjusted correctly, pump the jack up,
then place the jack into release. If both forks bottom-out at the same
time, the push rods are adjusted correctly. If one fork hits bottom
before the other, it needs to be adjusted. You can either lengthen the
push rod that hit first or shorten the push rod that hit second. Loosen
the nut on the eyebolt and turning the eyebolt one way or the other
to achieve the correct length. (20 minutes)
Check lifting link for out-of-round holes, cracks in welds or bent ears.
If any of these conditions exist, replace the lifting link. Also look
for worn bushings, missing shoulder bolts, missing lifting link pins
or the roll pins that fasten these parts to their mating parts.
Pump the jack up to make the bolt that fastens the lift ram to the frame,
more accessible. Then remove the bolt. Remove the shoulder bolts that
fasten the traverse to the lifting link. Pull the hydraulic unit and
traverse assembly away from the frame. Turn the frame over so that the
undercarriage is facing up. Disconnect the eyebolts from the lifting
link by removing the pins that secure the two pieces together. Drive
the roll pins out that fasten the lifting link pins to the frame. Pull
the lifting link pins out using vise-grips or pliers. This is easier
to do if you support the lifting link while pulling the pins out. (45
Turn the jack over so that the undercarriage is facing up. Position
the lifting link in the frame. Insert the lifting link pins and the
roll pins that fasten the lifting link pins to the frame. Attach the
push rods to the lifting link by inserting the pin through the eyebolt
and the ears of the lifting link. Secure the pin with its roll pins.
Turn the jack over and place the traverse and hydraulic unit assembly
into position. Insert the lift ram into the frame. Thread the shoulder
bolts through the ears of the lifting link and into the traverse to
secure it. Fasten the lift ram to the frame with the bolt. (45 minutes)
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Removal and Installation
Inspect handle for cracks and structural integrity. There should be
minimal side play in the handle socket. Check for worn bushings. If
bushings are not replaced regularly, the handle bracket holes can become
worn. Damaged holes cause pin failure and may require complete handle
replacement. Also inspect the roller for flat areas and wear. If any
of the above parts are worn more than 1/16", replace them.
Loosen adjustment nut on lower control rod, and slide the control rod
off the release lever. Remove the shoulder bolts from the handle bracket,
and the handle is now ready to come off. (10 minutes)
Set the handle on the hydraulic unit. The roller should be placed on
top of the pump piston. Push down on the handle to compress the spring
under the pump piston. Line up the holes and install the shoulder bolts.
(Tip: You may need someone to help you hold the handle in place in order
to keep the pump piston compressed while you install the shoulder bolts.)
Insert the lower control rod into the release lever and tighten the
adjustment nut. (15 minutes)
Control Rod Adjustment
Hold the release lever up and insert the lower control rod, with the
adjusting nut already on it, into the slot of the release lever. Place
the control lever into raise mode and pump the handle. The jack should
rise. If it doesn't lift, unthread the adjusting nut until pumping the
handle raises the jack.
Place the control lever into neutral mode and pump the handle. The jack
should not lift. If it does, the adjusting nut needs to be tightened
until the jack no longer rises. If the jack lowers when the control
lever is placed in neutral, the adjusting nut needs to be loosened until
the jack stops lowering.
Place the control lever into release mode and the jack should lower.
If not, the adjusting nut needs to be tightened. (10 minutes)
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Unit - Inspection
Inspect the outside of the pump for oil leaks. Test the unit, under
a load, to determine if there is a problem. This can be done by lifting
a heavy pallet and letting it stand for 15-20 minutes. Below are symptoms
and solutions to common hydraulic unit failures. If the following solutions
fail to correct the problem, a complete rebuild of the malfunctioning
unit may be necessary. Please refer to our catalog for information about
ordering the appropriate seal kit or take advantage of our hydraulic
unit exchange program.
Jack fails to lift load
• Air Lock in Pump - Place the control lever into release position,
then pump the handle rapidly about 10-15 times. (5 minutes)
• Low Fluid Level - With the jack in a lowered position, remove
filler plug. Using UNI-HO oil, fill the reservoir until the oil is level
with the fill plug hole. Bleed the unit (see Air Lock in Pump). Replace
the filler plug, creating a snug fit. Do not over-tighten. (5 minutes)
• Hand Control Out of Adjustment - See Control Rod Adjustment
under section heading Handle Removal and Installation. (10 minutes)
Jack fails to lower
• Look for any bent frame parts (lifting link, push rod, etc.).
Bent frame parts need to be replaced.
• The hand control may be out of adjustment (see Control
Rod Adjustment under section heading Handle Removal and Installation).
• Debris blocking an oil channel in the hydraulic unit. Contact
us for our hydraulic core exchange program.
Jack lifts in short increments
• Lack of oil pressure - see to Low Fluid Level.
• Reservoir filler plug leaking - Replace the washer and filler
plug and replenish oil, if necessary
(see to Low Fluid Level).
One fork lifts, the other
Check for damage in the following areas and their attached parts:
• Lifting link (lifting link pin and traverse shoulder pin)
• Load roller bracket (pivot axle)
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Unit Service Hints
• Tampering and abuse are two of the most common
problems. In most cases, minor repairs become
major when inexperienced people attempt to rebuild a hydraulic unit.
If you come across a unit that looks like it has been tampered with
or modified, inspect the unit carefully to be sure it can be rebuilt
or call Generic Parts Service for technical assistance.
• The ram is chromed and the pump piston polished
to a fine finish for maximum seal life and minimum oil leakage. If you
see these surfaces nicked or pitted, this will cause the unit to fail
in a short time. Replace any rusty or damaged parts that will cause
premature wear on their mating parts or the body of the hydraulic unit.
• Use UNI-HO hydraulic oil. Do not use automotive
oil or hydraulic brake fluid.
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Pump the jack to its maximum height and turn the jack
onto its side. Remove the steer wheels and axle (see Steer Wheels and
Axle Removal) and the snap ring under the traverse on the stem of the
hydraulic unit. Turn the jack upright; be careful no to damage the stem
of the hydraulic unit while lowering. Remove the bolt that fastens the
top of the ram to the frame. Lift the frame off of the ram, tip the
handle and hydraulic unit away from the frame, and rest both pieces
on the ground. Remove the ball on top of the ram and pull the hydraulic
unit out of the traverse. Remove the handle and handle bracket, if necessary
(see Handle Removal). (45 minutes)
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Slide the stem of the hydraulic unit into the traverse
with the traverse bearing already in place on the stem. Insert the ram
into the A-Frame with the ball positioned on the top of the ram and
secure the ram to the A-Frame with the bolt. Carefully turn the jack
onto its side, keeping the hydraulic unit in the traverse and frame.
Attach the snap ring to the stem of the hydraulic unit under the traverse.
Install the steer wheel assembly (see Steer Wheel and Axle Installation)
and the handle, if necessary (see Handle Installation). Bleed the hydraulic
unit (see Air Lock and Pump). (45 minutes)
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