VLriPPERT: HYDRAULIC CYLINDER TEST

HYDRAULICS

In the event that a coach equipped with hydraulic slide-outs begins to experience room drift, whether the room
drifts out after retract, or drifting in after extension, a test of the hydraulic cylinders should be performed.

Hydraulic Landing Gear (HLG), Rear Stab Jacks or Leveling Jacks
Retract jack in question. If retracting HLG, both jacks will retract. If retracting leveling jack, all jacks
will retract.

Once jack is fully retracted, remove the extend hose (hose located at the top of the jack). If testing
ROAD SIDE HLG or REAR STAB JACKS, the hose will be mounted to a red restricted flow valve block.

Do not attempt to EXTEND jack. The system will experience RAPID FLUID LOSS.
When the hose is removed, push the RETRACT button again.

If fluid comes from the jack while the retract button is being pressed, the hydraulic cylinder
is bypassing the internal seal and must be replaced. (See TI-120 for this procedure.)

If no fluid comes from the cylinder during this retract procedure, the cylinder is good.

If no fluid comes from the JACK but does come from the HOSE, test the opposite jack (HLG and
Rear Stabs only).

Be sure to reconnect and tighten EXTEND hose. System will experience rapid fluid loss if hose is not
reconnected.

Hydraulic Slide-out Cylinder - Retract Test

1. Retract (close) all slide-outs (rooms) completely.
2. Remove extend hose from slide cylinder.
3. Energize the pump to retract (close) room for up to 10 seconds.

Do not attempt to extend (open) room. The system will experience rapid fluid loss. Force of pressure
could result in bodily injury.
If fluid is coming from the port on the slide cylinder greater than a few drops, this will indicate internal
cylinder leaking (bypassing o f piston seal). If there is no fluid flow, reconnect the hose to the port on
the slide cylinder and tighten.

Repeat steps 2 through 4 for each slide-out until all slide-outs have been tested.

If fluid is observed streaming out of an extend line coming from the pump when testing for bypass,
please contact Lippert Customer Care Technical Support Team for further assistance.

Be sure to reconnect and tighten the hose before attempting to extend (open) the room or the system
will experience rapid fluid loss.

Rev: 03.10.26 Page 1 CCD-0001910

VLriPPERT: HYDRAULIC CYLINDER TEST

HYDRAULICS

Hydraulic Slide-out Cylinder - Extend test

1. Extend (open) all slide-outs (rooms) completely.
2. Remove retract hose from slide cylinder.
3. Energize the pump to extend (open) the room for up to 10 seconds.

Do not attempt to retract (close) the room. The system will experience rapid fluid loss. Force of pressure
could result in bodily injury.

If fluid is coming from the port on the slide cylinder greater than a few drops, this will indicate internal
cylinder leaking (bypassing of piston seal). If there is no fluid flow, reconnect the hose to the port on
the slide cylinder and tighten.

Repeat steps 2 through 4 for each slide-out until all slide-outs have been tested.

If fluid is observed streaming out of a retract line when testing for bypass, please contact Lippert
Customer Care Technical Support Team for further assistance.

Be sure to reconnect and tighten the hose before attempting to retract (close) the room or the system
will experience rapid fluid loss.

Rev: 03.10.26 CCD-0001910

(J uiPPERT HYDRAULIC CYLINDER TEST

HYDRAULICS

Cylinder Check - IRC (Individual Room Control)

Tools Required
* Two (2) hydraulic pressure gauges rated @3000 psi min.

« Standard set of open end wrenches
* Eye Protection

1. Retract all slide-outs. Check the fluid level in the reservoir. An empty or near empty reservoir is an
indication of an external leak. Check for any external leaks around the coach and inspect all hoses.
Note any leaks, hose bulging or ballooning. Check for any contaminants in the bottom of the reservoir.

Verify extend and retract hydraulic lines are installed in the correct port (Fig. 1).

Retract Extend

Val

Rod-end - Piston Rod Standard Slide-out Cylinder Cap-end - Stud

Verify the slide-outs are fully extended or fully retracted causing seal to compress. Briefly press the
extend or retract button again, depending on the disposition of the slide-out, to confirm full extend or
retract.

Check the system for internal leaks or “bypassing.” Hydraulic pressure gauges should be rated for at
least 3000 psi minimum. Install a pressure gauge using a female swivel “T” on the extend and retract
fittings of the hydraulic pump (Fig. 2).

NOTE: Fig. 2 shows the retract side pressurized. Fig. 3 shows the extend side pressurized. The opposite
side should have no pressure as indicated by the valves. Maintain constant ambient temperature
throughout test.

Fig. 2Fig. 2 Fig. 3Fig. 3
rs

Rev: 03.10.26 CCD-0001910

VLriPPERT: HYDRAULIC CYLINDER TEST

HYDRAULICS

Retract the slide-outs and record the pressure reading on the gauge. An internal bypass generally is
indicated by a significant drop in pressure on the retract side gauge and the slide-out(s) may drift. If
the loss of pressure on the retract side results in an increase in the pressure on the extend side, the
piston seal inside the slide-out cylinders have failed and the cylinders are bypassing. Individual slide-
outs can be tested if the unit is equipped with an IRC block. Close all valves in IRC except the one to be
tested. Follow the procedure found on Page 1 to isolate and test the first cylinder. Repeat this process
until the bypassing cylinder is found.

Hydraulic lines will be under pressure. Contact with fluid under pressure can cause bodily injury. Be
sure to wear eye protection. To avoid rapid fluid loss when opening a fluid line, make certain the
pressure is removed. Prior to opening the extend side of the system, retract the slide-out rooms. Prior
to opening the retract side of the system, extend the slide-out rooms.

If the retract side gauge drops pressure but the extend side does not, the pump has failed.
To remove and replace a cylinder, please follow the procedure found in TI-120.

Installing a new cylinder will introduce a small amount of air into the system. Extend all slide-outs
completely, holding the switch for 1-2 seconds at the end of the extend function. Immediately retract
all slide-outs and hold the switch in retract 1-2 seconds at the end of the cycle. Check the reservoir
for foam or bubbles. This indicates air has been purged from the system. Wait 15-20 minutes before
cycling the slide-outs again to prevent reintroducing the air from the reservoir back into the system
and to keep the pump motor from overheating. Il - 118 can also be noted for a purge procedure.

Once the system leak has been resolved, pressurize the system to perform a leak test overnight, or over
the next several hours.
NOTE: Ambient temperature must be maintained for the duration of the overnight test to check the effect
of pressure on the system. If no leak is detected at the conclusion of the test, the repair is complete.

6. If the system still has a pressure leak, the system may be contaminated and would need a flush and fill
procedure performed. See procedure on Page 5.

Rev: 03.10.26 CCD-0001910

VLiPPERT HYDRAULIC CYLINDER TEST

HYDRAULICS

Flush and Fill Procedure

Extend all systems.

Locate all of the slide-out cylinders.

Go to furthest cylinder from pump.

Remove retract line on cylinder furthest from pump.

Place into jug of clean fluid.

Attach 4’ utility hose to cylinder.

Put hose in another jug.

Retract all systems.

Remove utility hose.

Reattach line.

Go to extend side and repeat steps.

Remove clean fluid out of one jug with hose removed from cylinder.
13. Place utility hose into another jug and drain the contaminated fluid into a clean container.

Fluid Requirements - For Keystone Units Only

Keystone RV utilizes a 32 wt. hydraulic fluid. In the event of low fluid, the use of 32 wt. hydraulic fluid only is
the recommended fluid for replacement.

Asa supplier of a broad array of highly-engineered components in the recreation and transportation product markets, safety, education and customer satisfaction are
our primary concerns. Should you have any questions, please do not hesitate to contact us at 432-LIPPERT (432-547-7378) or by email at [email protected].
Self-help tips, technical documents, product videos and a training class schedule are available at lippert.com or by downloading the LippertNOW app.

Rev: 03.10.26 Page 5 CCD-0001910