Ask Dave: My RV hydraulic jacks “twang” and retract overnight. What should I look for?

Hi, Dave,
First, I want to tell you how much I enjoy your daily articles in RV Travel. Thanks!  I’ve learned a lot. We have a 2017 Pace Arrow 36U with a Power Gear self-leveling hydraulic jack system. After we set up and have the RV level, we can hear a popping sound with a spring “twang” and think the jacks must be losing pressure. By morning we need to relevel the coach. How do we fix this problem—bleed the system, replace valves or solenoids, or…? Thanks for your help. —Howard, 2017 Pace Arrow 36U

Hi, Howard,
Thanks for following us on RVtravel.com and the opportunity to assist with some suggestions on your Power Gear^® Leveling System.

When troubleshooting anything related to a mechanical issue, we always start at the first step, checking the fluid level in the reservoir. I know this sounds very basic; however, you would be amazed at how many owners do not know how the system works and its basic maintenance.

Purge the hydraulic jacks system of air bubbles

Assuming you have checked the fluid level, the next step would be to purge the hydraulic jacks system of air bubbles. That can be done by extending and retracting the jacks several times and watching the reservoir to see if there are bubbles that are evident. I also assume your 2017 has slide rooms. One or more might also utilize the Power Gear hydraulic system, so they should be extended and retracted, as well.

Since the rig is almost 8 years old, it would also be wise to flush the hydraulic fluid and replace it with new fluid. Power Gear, which is now owned by Lippert, recommends flushing the system every 24 months to get rid of contaminants, burnt fluid, and moisture. Since it is a closed system, this might be a little premature; however, temperature can play a big part in how well fluids hold up.

Remove the fluid in the reservoir

Rather than disconnecting lines and totally flushing the system, I would remove the fluid in the reservoir with a hand pump and add Type A automatic transmission fluid (ATF) such as Dexron III. Power Gear also recommends using Mercon V for units operating in extreme temperature swings. If you are going to be in cold temperature regions that are below zero degrees, Power Gear recommends the following:

Mobil DTE 11M, Texaco Rando HDZ-15HVI, Kendall Hyden Glacial Blu, or any Mil. Spec. H5606 hydraulic fluids are recommended for cold weather operation.

Make sure the hydraulic jacks and slide rooms are all retracted when doing this, then extend and retract them several times after adding the new fluid. If you see bubbles in the reservoir, you had air in the lines. I would then repeat the procedure of removing the fluid, adding new, and running the jacks and rooms in and out. This should mix the fluid and get good, new fluid in all the systems.

Power Gear’s maintenance tips

Here is what Power Gear recommends for maintenance.

1. Check the fluid level every month. Fill the reservoir with the jacks in the fully retracted position. On vertical pump assemblies, the fluid should be within 1/4 inch of the fill port lip and checked only with all jacks retracted. On horizontal pump assemblies, the fluid level should be approximately 1.75” on the dipstick and checked only with all jacks retracted.
2. Change fluid every 24 months.
3. Inspect and clean all hydraulic pump electrical connections every 12 months.
4. Remove dirt and road debris from jacks as needed.
5. If jacks are down for extended periods, it is recommended to spray exposed chrome rods with a silicone lubricant every seven days for protection. If your coach is located in a salty environment (within 60 miles of coastal areas), it is recommended to spray the rods every 2 to 3 days.

If the problem still exists, it is most likely a seal on one or more of the valves that are designed to hold the pressure and not a repair that I would advise to tackle on your own.

Popping sound

However, the popping sound you indicated is interesting as a slight decrease of pressure in the system should not make the retraction spring pop as it would just be retracting. Does the popping sound happen when you retract the jacks normally? Can you isolate which jack this is happening to? My guess would be that it might be a loose jack mount or a hairline crack on a weld somewhere. Any movement of the jack or outriggers would create a shift and cause the springs to move or “twang,” which is not normal.

 You might also enjoy this from Dave 

Why does my RV drop like a rock when hydraulic jacks are retracted?

Dear Dave,
My Class C will level easily when using auto level, but when it is time to retract, the motorhome drops like a rock. Recently, the violent drop caused the black ABS drain line in the slideout to break. The RV service center along with Forest River say the unit is working correctly; however, it never worked that way before when I did an auto retract. What’s the solution? —Harry, 2019 Forest River Forester 3271SF

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

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