dewald hydraulic pump troubleshooting(Solutions 2023)

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.

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

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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!