Quick Jack Tripping Breaker - Lowering Only

[J5hort]

Hi All,
Reaching out to any Quick Jack owners who may have had this problem. I have the old Buick up on the jacks for some rocker repair. Attempted to lower the jacks today and my breaker keeps tripping. Oddly enough, the pump operates with "Up" button, but trips breaker when "Down" button is pressed. I took apart controller and jumped wires to bypass "Down" button and it still trips. Also removed cover on control unit to inspect wires and all looks clear. Any ideas on this?

 

[Chipm]

Sounds like a wiring issue inside the box. It definitely uses more amps on "up" than "down."

 

[rust in the eye]

So these quick jacks "power" down?
Obviously no experience with one here but if pump runs for down I'm wondering if it isn't trying for up instead. Does the pump sound sound like it is straining? Cavitating? Maybe some valving issue?
Again, no experience just thinking out loud since you haven't any replies

 

[mike93lx]

So these quick jacks "power" down?
Obviously no experience with one here but if pump runs for down I'm wondering if it isn't trying for up instead. Does the pump sound sound like it is straining? Cavitating? Maybe some valving issue?
Again, no experience just thinking out loud since you haven't any replies

No, they are gravity down and the pump doesn't run

 

[OccupantRJ]

From this quick jack wiring diagram online, it does not get much simpler. It just about has to be a shorted lowering valve (solenoid) or wiring from the lowering button feeding it. Has the wiring become pinched somewhere?

 

[J5hort]

Wires all look good in control unit and handheld. I was able to swap button wiring in handheld unit to see if it was the Down button. Down button wired to Up worked fine. I did have to get the Buick off the jacks which was a pain. So the QJs are out from under the car and still in up position.

So replacing the valve/solenoid may be the next step... any one done this. Looks pretty straightforward.

 

[TN_Jim]

Just a reminder, the QJ has position locks. They physically prevent the jacks from going down. Did you release the locks before lowering?

 

[OccupantRJ]

I would mark and detach the wires going to the solenoid at the hand control, then do resistance test between the two wires. After that I would test for continuity from one wire at a time to the motor/pump housing to see if the solenoid winding is possibly shorted to the housing. You could also attach a power cord directly to the solenoid wires alone or with a switch inline to bring diagnostics level down to the solenoid itself. That is assuming that the solenoid coil is 120 volt.

 

[J5hort]

Just a reminder, the QJ has position locks. They physically prevent the jacks from going down. Did you release the locks before lowering?

Yes, raised jack to unlock/release cam and cam bar, problem happened when attempting to lower. Immediate breaker pop.

 

[J5hort]

I would mark and detach the wires going to the solenoid at the hand control, then do resistance test between the two wires. After that I would test for continuity from one wire at a time to the motor/pump housing to see if the solenoid winding is possibly shorted to the housing. You could also attach a power cord directly to the solenoid wires alone or with a switch inline to bring diagnostics level down to the solenoid itself. That is assuming that the solenoid coil is 120 volt.

I'll have to get the multimeter out...

 

[Wrench-Polisher]

He just a quick question. When was the last time you checked the air pressure in BOTH cylinders?

 

[RTM]

Looking at the wiring diagram linked above, there should be a very small window which is "down only" wiring.

You are certain the up portion works ok, as you noted by switching button wires, and by releasing the locks. Looks like the KM (relay), which starts the motor, is controlled by the up button, is hard plumbed into Up mode, and the SV is only for down, no motor involved. So wherever the LINE power splits between the KM and the SV is your start of where to look, and end wherever you switched the PB wires. And the SV (Solenoid Valve) is the majority of that. Should be some non zero amount of resistance through the coil. But not much, usually less than a few ohms I think.

 

[J5hort]

Did not get a chance to check voltages/resistance. Needed to get jacks out of the way and they were stuck in up position.I was able to get out from under car with hand jack and jack stands. I tried loosening bleed screws, but no luck, so I had to disconnect hydraulic coupling and squirt it out.

 

[Wrench-Polisher]

Did not get a chance to check voltages/resistance. Needed to get jacks out of the way and they were stuck in up position.I was able to get out from under car with hand jack and jack stands. I tried loosening bleed screws, but no luck, so I had to disconnect hydraulic coupling and squirt it out.

Your jacks have a place where you pressurize them with air. Were you able to access those valves and check the pressure?

 

[J5hort]

Your jacks have a place where you pressurize them with air. Were you able to access those valves and check the pressure?

Yes, checked a week ago and they were at pressure.

 

[Wrench-Polisher]

Yes, checked a week ago and they were at pressure.

50 psi?

 

[u2slow]

Is this a regular breaker? Or a gfci/AFCi breaker?

 

[johnre]

I was able to swap button wiring in handheld unit to see if it was the Down button. Down button wired to Up worked fine.
.....
So replacing the valve/solenoid may be the next step... any one done this.

Agreed, looking at the schematics provided by @OccupantRJ, about all this could be is the down valve / solenoid is defective and shorted.

FWIW, my BL-5000SLX when new had a down valve / solenoid that occasionally stuck open, causing the power up function to not work until it became unstuck again - the pump would run but it would just circulate hydraulic fluid out of the reservoir and back in. That was handled as a warranty replacement; QuickJack just sent me a new power unit and I returned the defective one to them.

My guess is that this was caused by stickiness on the hydraulic side of it, not a defect on the electrical side. I say this because the red light on the down valve / solenoid was going out when I released the down button, indicating the solenoid was no longer powered.

One good thing came out of it; it reminded me again to never trust being under hydraulics without a mechanical lock.

 

[J5hort]

50 psi?

Yes.

 

[J5hort]

UPDATE: Replaced the solenoid switch and it no longer trips breaker. However, the jacks still will not lower. They have been bled and have 50psi in the cylinders. I am going to replace the actual valve to see if that solves the problem. Raising jack is no problem so hydraulic pump seems to be working.

 

[mike93lx]

They won't lower at all or just without weight on them?

 

[J5hort]

Both. Have to unscrew bleed screws to get them down. Very messy.

 

[johnre]

UPDATE: Replaced the solenoid switch and it no longer trips breaker. However, the jacks still will not lower. They have been bled and have 50psi in the cylinders. I am going to replace the actual valve to see if that solves the problem. Raising jack is no problem so hydraulic pump seems to be working.

Does the red light on the solenoid light up when you press the "Down" button? And if so, can you hear anything move inside the hydraulic system or hear the 60 Hz hum in the solenoid?

Probably will help to change the valve itself as well, as you suggest - per my post #18 above, I had stickiness in this valve just like you, but it was the opposite kind of failure; it stuck open, not closed, so my frames wouldn't raise.

 

[J5hort]

Light lights, no hum. Ordered valve, should be here in a few days. How did I ever do the hand jack and jack stand thing.... In February... on a gravel driveway... with mittens on...

 

[ClassicFiat]

Light lights, no hum. Ordered valve, should be here in a few days. How did I ever do the hand jack and jack stand thing.... In February... on a gravel driveway... with mittens on...

J5 - I just had the same thing happen. Was it definitely the valve? Any advice now that you have gone through it?

 

[J5hort]

I bought a new solenoid as the old one was not showing the red active light when attempting the UP button. The unit did get wet, so I thought it shorted out. Was still having problem so I bought a valve as well. I have not been able to test it yet.

 

[ClassicFiat]

I bought a new solenoid as the old one was not showing the red active light when attempting the UP button. The unit did get wet, so I thought it shorted out. Was still having problem so I bought a valve as well. I have not been able to test it yet.

Thanks. I may be doing the same. Will post here if it solves the issue