If you are in the process of troubleshooting a dewald hydraulic pump, you may realize how frustrating it can be. There are many factors that need to be considered when this problem occurs. But you can easily recognize the problem when some of these signs become noticeable. Here are the most common signs of a faulty dewald hydraulic pump.
❗❗❗ Troubleshooting any Direct Current (DC) electrical system should be done with caution and by a trained technician. Anyone unfamiliar with electrical systems should not attempt the troubleshooting procedures listed in this guide.Failure to follow these guidelines could result in personal injury or even death.
Pump assembly key
Pump assembly key is very important. Only by understanding the structure can we troubleshoot better. We will explain it to you in detail through the following pictures.
All | All pumps discussed in this manual |
1 | BL 3 or 4 quart assy |
2 | BL 3 or 4 quart with selector manifold assy. |
3 | Double or triple ESV assy. |
4 | Quad ESV assy. |







Room(s) will not extend, pump does not run
Pump assy. | Probable Cause | Corrective Action |
AlI | Low or no voltage at pump assembly | Verify that the battery is fully charged and connected to the electrical system. |
AlI | 5 amp fuse blown | Check 5 amp in-line fuse at pump assembly. Replace as necessary. |
AlI | Bad connection of motor ground wie at pump | Check grounding of black wire coming directly out of 12VDC motor at the pump assembly. |
AlI | Motor or pump has failed | Check for continuity between blue and black wires of 12VDC motor. lf no cotinuit replace motor. If contiuity is found, then replace pump/motor assembly. |
1,2,4 | Solenoid”A”faulty | With any room extend switch pushed, small post of solenoid “A” should show 12V+.f so, then two large posts of solenoid”A” should have continuity across them. If no contiuity, replace solenoid. |
1,2,4 | No signal to pump assembly | Check for 12V+ at the pump assembly on the copper buss bar that ties solenoids”A” and”B” together. If power is found, jumper the two large posts on solenoid””A” to see if pump willl run. If pump Tuns then continue trouble shooting system to isolate problem. |
3 | No signal to relay pack from wall switch(es) | The blue wire from the wall switches to the relay pack should show voltage when any room extend switch is pressed. If no voltage is found, then replace wali switch(es) as necessary. |
3 | No signal from relay pack to 12VDC motor | With any wall swich pressed, the lug on the relay pack with the blue wire attached should show 12V+. If not, then replace relay pack. |
4 | No signal to solenoid”A” fom cube relay | With any room extend switch pressed, terminal 87a of cube relay should show 12V+. If so, then terminal 30 should show 12V+. If no voltage at 30, then replace cube relay. |
Room(s) will not extend, pump does run
Pump assy. | Probable Cause | Corrective Action |
AlI | L _ow fluid level | Fill tank to proper level. See Preventive Maintenance and Recommended Fluids, pg21. |
AlI | The siliver, knurled knob on the hand pump is open | Knurled knob must be turned clockwise for normal operation. |
3,4 | Faulty coi(s) | Check for continuity across the two yellow wires coming out of each of the coils. If no continity replace coil(s)、. |
3,4 | Valve coils miswired | Check wiring diagrams. |
Room extends, but erratically
Pump assy | Probable Cause | Corrective Action |
AlI | Room is out of synchronization | See “cable adjustment, pg 20. |
AlI | Room seals or rails dry | Lubricate room seals and rails with slicone spray. |
AlI | Internal leak in slide room cylinder | See diagnosing a Dewald cylinder for internal leakage” ,p9 19. |
Pump does not shut off when extend switch is released
Pump assy | Probable Cause | Corrective Action |
1,2,4 | Solenoid“A”faulty | Remove blue wire from large top post of solenoid“A”.Test across the two large posts of solenoid“A”for continuity while the extend switch is pressed.If continuity remains after switch is released, then replace solenoid. |
1,2,4 | Faulty switch | Remove blue wire from large top post of solenoid“A”.Check for voltage at small bottom post of solenoid“A”while the extend switch is pressed.If voltage remains after switch is released, then replace switch. |
3 | Relay pack faulty | Remove large blue wire from lug of relay pack.Test across that lug and the center lug(red wire) for continuity while the extend switch is pressed.If continuity remains after switch is released, then replace relay pack. |
3 | Faulty switch | Remove large blue wire from lug of relay pack.Check for voltage at blue wire in relay pack coming from switches while the extend switch is pressed.If voltage remains after switch is released, then replace switch. |
Wrong room extends
Pump assy | Probable Cause | Corrective Action |
2 | Wrong selector knob chosen | Chose correct selector knob. |
2 | Faulty selector knob | Remove selector knob from manifold assembly and inspect the end for damage or contamination. Swap with a known good valve on manifold. If symptom swaps, then replace selector knob. If symptom does not swao, then continue troubleshootina to isolate defective comoonent. |
2, 3,4 | Cylinders plumbed to manifold incorrectly | Check plumbing of cylinders (See hydraulic diagrams, pg. 17) |
3, 4 | Stem valves are in manual override position | Turn slotted set screws at tlhe end of the valves counterclockwise until they stop. If system has red knobs instead of set screws, turn knobs until they “snap” back into position (see oo 6). |
3, 4 | Coils and/or switches wired incorrectly | Check wiring of coils and switches according to the wiring diagrams contained in this manual. |
3, 4 | Faulty stem valve | Swap suspected stem valve with a known good stem valve on manifold. If symptom swaps, replace stem valve. If stem valve has red knurled knob on the end (old style), then valve and coil must be replaced. |
Room “creeps” back in once extended
Pump assy | Probable Cause | Corrective Action |
All | A leak somewhere in system | Check all hoses, hose connections, pump assembly, etc for any visible fluid leak. Repair any found leaks as necessary. |
All | Air trapped in system | Verify that hose connection ports on cylinder are pointing as close to 12 o’clock as possible. Cycle room(s) to complete extension and retraction allowing system to rest 5 minutes in-between cycles. Do this 4 times. This should purge the air from the system |
All | Bad piston seal in cylinder(s) | Test for internal cylinder seal leakage per instructions on pg 19. |
All | Bad o-ring seal between hand pump and pump assembly | Install o-ring kit #800176 as per pg 22. |
All | The silver, knurled knob on the hand pump is open | Knurled knob must be turned clockwise for normal operation. |
1 | Bad piston seal in cylinder(s) | On the BL 4 quart pump assembly where 2 or more rooms are teed together, a bad cylinder on one room can make another room creep back in. Be sure to check all cylinders for internal piston seal leakage on these systems |
3, 4 | Stem valves are in manual override position | Turn slotted set screws at the end of the valves counterclockwise until they stop. If system has red knobs instead of set screws, turn knobs until they “snap” back into position (see pg 6). |
3, 4 | Faulty stem valve | Swap suspected stem valve with a known good stem valve on manifold. If symptom swaps, replace stem valve. If stem valve has red knurled knob on the end (old style), then valve and coil must be replaced. |
Room(s) will not retract, pump does not run
Pump assy. | Probable Cause | Corrective Action |
All | Low or no voltage at pump assembly | Verify that the battery is fully charged and connected to the electrical system. |
All | 5 amp fuse blown | Check 5 amp in-line fuse at pump assembly. Replace as necessary. |
All | Bad connection of motor ground wire at pump | Check grounding of black wire coming directly out of 12VDC motor at the pump assembly. |
All | Motor or pump has failed | Check for continuity between blue and black wires of 12VDC motor. If no continuity, replace motor. If continuity is found, then replace pump/motor assembly. |
1, 2, 4 | Solenoid “B” faulty | With any room retract switch pushed, small post of solenoid “B” should show 12V+.If so, then two large posts of solenoid “B” should have continuity across them. If no continuity, replace solenoid. |
1, 2, 4 | No signal to pump assembly | Check for 12V+ at the pump assembly on the copper buss bar that ties solenoids “A” and “B” together. If power is found, jumper the two large posts on solenoid “B” to see if pump will run. If pump runs then continue trouble shooting system to isolate problem. |
3 | No signal to relay pack from wall switch(es) | The green wire from the wall switches to the relay pack should show voltage when any room retract switch is pressed. If no voltage is found, then replace wall switch(es) as necessary. |
3 | No signal from relay pack to 12VDC motor | With any wall switch pressed, the lug on the relay pack with the green wire attached should show 12V+. If not, then replace relay pack. |
4 | No signal to solenoid “B” from cube relay | With any room retract switch pressed, terminal 87a of cube relay should show 12V+. If so, then terminal 30 should show 12V+. If no voltage at 30, then replace cube relay. |
Room(s) will not retract, pump does run
Pump assy | Probable Cause | Corrective Action |
All | Low fluid level | Fill tank to proper level. See Preventive Maintenance and Recommended Fluids, pg 21. |
All | System overfilled with fluid | Drain tank to proper level. See Preventive Maintenance and Recommended Fluids, pg 21. |
3, 4 | Faulty coil(s) | Check for continuity across the two yellow wires coming out of each of the coils. If no continuity, replace coil(s). |
3, 4 | Valve coils miswired | Check wiring diagrams. |
Room retracts, but erratically
Pump assy | Probable Cause | Corrective Action |
All | Room is out of synchronization | See “cable adjustment”, pg 20. |
All | Room seals or rails dry | Lubricate room seals and rails with silicone spray. |
All | Internal leak in slide room cylinder | Check cylinder for internal piston seal leakage. See “diagnosing a Dewald cylinder for internal leakage” , pg 19. |
Pump does not shut off when retract switch is released
Pump assy | Probable Cause | Corrective Action |
1, 2, 4 | Solenoid “B” faulty | Remove green wire from large top post of solenoid “B”. Test across the two large posts of solenoid “B” for continuity while the retract switch is pressed. If continuity remains after switch is released, then replace solenoid. |
1, 2, 4 | Faulty switch | Remove green wire from large top post of solenoid “B”. Check for voltage at small bottom post of solenoid “B” while the retract switch is pressed. If voltage remains after switch is released, then replace switch. |
3 | Relay pack faulty | Remove large green wire from lug of relay pack. Test across that lug and the center lug (red wire) for continuity while the retract switch is pressed. If continuity remains after switch is released, then replace relay pack. |
3 | Faulty switch | Remove large green wire from lug of relay pack. Check for voltage at green wire in relay pack coming from switches while the retract switch is pressed. If voltage remains after switch is released, then replace switch. |
Wrong room retracts
Pump assy | Probable Cause | Corrective Action |
2 | Wrong selector knob chosen | Chose correct selector knob |
2 | Faulty selector knob | Remove selector knob from manifold assembly and inspect the end for damage or contamination. Swap with a known good valve on manifold. If symptom swaps, then replace selector knob. If symptom does not swap, then continue troubleshooting to isolate defective component |
2, 3, 4 | Cylinders plumbed to manifold incorrectly | Check plumbing of cylinders (See hydraulic diagrams, pg. 17) |
3, 4 | Stem valves are in manual override position | Turn slotted set screws at the end of the valves counterclockwise until they stop. If system has red knobs instead of set screws, turn knobs until they “snap” back into position (see pg 6). |
3, 4 | Coils and/or switches wired incorrectly | Check wiring of coils and switches according to the wiring diagrams contained in this manual. |
3, 4 | Faulty stem valve | Swap suspected stem valve with a known good stem valve on manifold. If symptom swaps, replace stem valve. If stem valve has red knurled knob on the end (old style), then valve and coil must be replaced. |
Room “creeps” back out once retracted
Pump assy | Probable Cause | Corrective Action |
All | A leak somewhere in system | Check all hoses, hose connections, pump assembly, etc for any visible fluid leak. Repair any found leaks as necessary. |
All | Air trapped in system | Verify that hose connection ports on cylinder are pointing as close to 12 o’clock as possible. Cycle room(s) to complete extension and retraction allowing system to rest 5 minutes in-between cycles. Do this 4 times. This should purge the air from the system. |
All | Bad piston seal in cylinder(s) | Test for internal cylinder seal leakage per instructions on pg 19. |
All | Bad o-ring seal between hand pump and pump assembly | Install o-ring kit #800176 as per pg 22. |
All | The silver, knurled knob on the hand pump is open | Knurled knob must be turned clockwise for normal operation. |
1 | Bad piston seal in cylinder(s) | On the BL 4 quart pump assembly where 2 or more rooms are teed together, a bad cylinder on one room can make another room creep back out. Be sure to check all cylinders for internal piston seal leakage on these systems. |
3, 4 | Stem valves are in manual override position | Turn slotted set screws at the end of the valves counterclockwise until they stop. If system has red knobs instead of set screws, turn knobs until they “snap” back into position (see pg 6). |
3, 4 | Faulty stem valve | Swap suspected stem valve with a known good stem valve on manifold. If symptom swaps, replace stem valve. If stem valve has red knurled knob on the end (old style), then valve and coil must be replaced. |

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dewald hydraulic pump parts
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- Return all rooms and leveling legs to the travel/storage position.
- Disconnect the battery for the coach and pump system.
- Drain the tank of oil with a siphon.
- Mark each hose, and wire for their respective positions.
- Remove each hose from the pump assy. and insert the ends into a bucket in case of leakage.
- Remove the power leads to the pump motor (green, blue, and black).
- Remove the pump from its mounting bracket. Take it to a clean, well-lighted workbench for disassembly.
- Remove the tank; drain any remaining fluid and clean inside of tank with a lint free cloth.
- Remove the hand pump from the assembly by removing the two nuts and lock-washers. Removal may be difficult with the inlet strainers in place. While pulling the hand pump off of the hollow tubes, pivot the hand pump down to clear the strainers after it clears the tubes.
- Insert a long Allen wrench small enough to fit through the holes in the hollow tubes to check them to make sure they are tight (right hand thread).
- Clean the components before re-assembly.
- Install 2 new o-rings (VA25400) onto each tube (4 total), lubricate them with Dexron III.
- Re-install the hand pump onto the pump assy.
- Install one white o-ring (VA20000) onto each of the two tubes. Push the assembly together as much as possible to align the housing and tubes so the o-rings will be seated correctly.
- Re-install the nuts onto the tubes and tighten to 70 inch/ pounds.
- Install new o-rings (VA14350 and VA25300, 1 each) onto hand pump assembly and re-install the tank.
- Re-install the pump components in reverse order of disassembly making sure to match the hose and wire markings.
- Re-fill the tank with Dexron III fluid until ½” from the top of the tank.
- Run the rooms and or leveling legs to full extension, wait 30 seconds and retract the rooms and leveling legs. Repeat this 4 times. This should completely purge air from the system.
- Check the fluid level in the tank with all rooms and jacks retracted. Fill to proper level if necessary.
- Test the system for proper operation, leaks, etc.
Part # | Description | Color | A | B | C | D | E |
130-1155 | 1.5×24 ext | Black | 25.25 | 1.75 | 18.37 | .75 | 75 |
130-1156 | 1.5x 24 non ext | Black | 25.25 | 1.75 | 6.75 | .75 | .75 |
130-1157 | 1.5×41 ext | Black | 42.25 | 1.75 | 18.37 | .75 | 75 |
130-1226 | 1.5X 42 non ext | Black | 45.25 | 1.75 | 7.0 | .75 | .75 |
130-1159 i i | 1.5x 38 ext | Black | 42.25 | 1.75 | 18.37 | .75 | 75 |
CW10320 | 2x 24 non ext | Green | 25.0 | 2.38 | 7.0 | .75 | .75 |
CW10323S | 2x 32 non ext | Yellow | 32.75 | 2.38 | 7.0 | .75 | 75 |
cw1 0324S | 2x 32 non ext | Yellow | 33.0 | 2.38 | 7.0 | .75 | 75 |
+CW10325S | 2×38 non ext | Gray_ | 39.0 | 2.38 | 7.0 | .75 | .75 |
CW1 0326S | 2x 38 ext | Gray | 39.0 | 2.38 | 18.37 | .75 | 75 |
*CW10327 | 2×40 non ext | Green | 41.0 | 2.38 | 7.0 | .75 | .75 |
CW10329 | 2×48 non ext | Yellow | 49.0 | 2.38 | 7.0 | .75 | 75 |
*CW10400 | 2 x40 (Dutchmen) | Black | 36.75 | 2.38 | 7 | .75 | .75 |
CW10416 | 1.125x 16.5 non ext | Black | 17.38 | 1.38 | 2.75 | .625 | .625 |
+CW10420 | 1.5x 20 non ext | 23.5 | 1.875 | 3.5 | .75 | .75 | |
+CW10500 | 2×44 non ext | Blue | 45.0 | 2.38 | 7.0 | .75 | .75 |
+CW10520 | 1 5x 20 nonext | Gray | 23.12 | t 1.75 | 7.25 | .75 | .75 |
CW10524S | 1.5 x 24 non ext | Gray | 27.5 | 1.75 | 7.0 | .625 | .75 |
+CW10534 | 1.5x 34 non ext | Black_ | 37.12 | 1.75 | 7.25 | .75 | .75 |
+CW10538 | 1.5x 38 non ext | 39.25 | 1.38 | 7.0 | .75 | .75 | |
+CW10620 | 1.5x 20 non ext | 23.5 | 1.88 | 7.25 | .625 | .625 | |
CW10638 | 1.5x 38 non ext | Purple | 39.25 | 1.75 | 6.75 | .75 | .75 |
CW10640 | 1.5×40 non ext | Green | 41. 25 | 1.75 | 7.0 | .75 | .75 |
CW10719 | 1.5x 19 ext | Blue | 20.25 | 1.75 | 18.62 | .75 | .75 |
CW10720 | 1.5×20 non ext | Gray_ | 20.88 | 1.75 | 7.12 | .75 | .75 |
+CW10724 | 1.5 x24 non ext | Green | 25.25 | 1.75 | 7.0 | .75 | 75 |
CW10726 | 1.5x 26 ext | Red | 27.25 | 1.75 | 18.62 | .75 | .75 |
CW10729 | 1.5x 29 non ext | Red | 30.25 | 1.75 | 4.0 | .75 | .75 |
CW10732 | 1.5×32 ext | Yellow | 33.25 | 1.75 | 18.62 | .75 | .75 |
+CW10738 | 1.5x 38ext | Gray | 39.25 | 1.75 | 18.62 | .75 | .75 |
+CW10741 | 1.5×41 ext | Blue | 42.25 | 1.75 | 18.62 | .75 | .75 |
+CW10820 | 1.5x 20 non ext | Purple | 20.88 | 1.75 | 3.5 | .75 | .75 |
+CW10824 | 1.5×24 ext | Green | 25.25 | 1.75 | 18.62 | .75 | 75 |
DN11816 | 1.5x 40(Dutchmen) | _Black | 40.5 | 1.75 | 3.18 | .75 | |
*DN11997S | 1.5×38 | Black | 41.5 | 1.75 | 7.0 | .625 | .625 |
+CW10120 | 2×32 | 33.0 | 2.38 | 7.0 | 1.12 | n/a | |
*CW10140 | 2×17 | Black | 18.0 | 2.38 | 7.0 | 1.12 | n/a |
CW10175S | 2×24 | Red | 25.0 | 2.38 | 7.0 | 1.12 | n/a |
+CW10200 | 2×32 | Yellow | 33.0 | 2.38 | 7.0 | 1.12 | n/a |
CW10300S | 2×38 | 39.0 | 2.38 | 7.0 | 1.12 | n/a | |
CW10410 | 2x 44 | Gray | 45.0 | 2.38 | 7.0 | 1.12 | n/a |
dewald hydraulic pump troubleshooting video
dewald hydraulic pump troubleshooting FAQ
If you’re looking for information about dewald hydraulic pump troubleshooting FAQs, you’ve found the right place. Here you’ll find loads of practical tips and hints to get you started with a new business or to help you grow your existing one.
what type of hydraulic fluid for dewald slide out pump?
Synthetic Hydraulic Fluids
These fluids are made from chemicals such as ester or phenol and have been used in place of petroleum based oils for a number of years now. These fluids have a number of advantages over the conventional mineral oil based fluids including:
Higher temperature range – They are able to operate at higher temperatures than their petroleum counterparts, making them ideal for use with high temperature machinery such as the DeWalt slide out pump;
Better lubricity – Synthetic fluids possess higher lubricity than their traditional mineral oil counterparts, meaning they are less likely to cause wear on moving parts;
Reduced fluid degradation – Synthetic fluids do not degrade at the same rate as mineral oils do when exposed to sunlight or UV light (due to their chemical makeup);
dewald hydraulic pump manual can be found there?
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Dewald hydraulic pump manual
dewald hydraulic pump Slide out not working?
The Dewalt slide-out works fine when it’s at full extension. But if you try to retract it, it just stops and won’t go back in. I’ve checked all of the hoses and they all seem to be connected. The only thing that is different than when I first bought it is the fluid level hasn’t gone down since I filled it up about a year ago. There was no leakage or anything like that involved with filling the fluid, so I don’t think there’s a leak in the system.
The pump is probably overfilled with oil and not draining properly. Try removing some oil from the reservoir using a turkey baster or similar device until you’re sure that there’s enough room for air to enter before starting up again (you can always put more back in later if needed).
Dewald hydraulic pump failed?
In the photo below, the red arrow points to the failed Dewald hydraulic pump. This failure occurred after only 3 years of operation. The pump runs on a shaft that is connected to the engine crankshaft by means of a crank pulley. When this pump fails, it usually means that the crankshaft is bent and must be replaced as well as the hydraulic pump.
The part number for this particular Dewald hydraulic pump is HC-2S-A-112-0210. The model number is HC-2S-A-112-0210 and it has 2 cylinders with a stroke length of 1″ (25mm). Each cylinder has an operating pressure rating of 3000 psi (207 bar). The maximum flow rate for each cylinder is 6 GPM (26 L/min).
Hi all! I hope you found this post to be helpful. If you have any questions, or would like advice on a different hydraulic pump please feel free to contact us and we can connect you with the technician who specializes in that pump type. Thanks!