How to Check Hydraulic Fluid On RV (Adding Hydraulic Fluid)

It is like falling off a log. If you know how to check your power steering, brake, and other fluids, then you will know how to check your hydraulic fluid. Engine and system manufacturers know you need to do maintenance thus they have made it easy for you to see how much fluid is in your systems.

For most hydraulic systems, you will have a reservoir or tank that holds the majority of the fluid. Then the cap will have a built-in dipstick attached to it. Just pull the cap off and check the lines on the dipstick to see how much fluid is inside the reservoir and that is it.

To learn more about this simple process, just continue to read our article. It has the information you want to know about so you can do your own hydraulic fluid checking and save time and money.

How do I Know If My Hydraulic Fluid is Low?


There are 6 basic signs that tell you that you are getting low on hydraulic fluid:

- Decreased hydraulic system performance

- Unusual noises, such as whining or grinding

- Increased system temperature

- Reduced or erratic movement of actuators

- Leakage from the hydraulic system

- Increased wear and tear on components

These signs may not happen at the same time so keep your eye open for just one of them. If you see any one of these signs taking place, check your hydraulic fluid reservoir.

If it is low, add enough fuel to be an inch below the fill line or opening. You do need to add a lot most of the time unless you are really low on fluid. The tricky part will be the location of the hydraulic fluid reservoir. Depending on the system that location may not be easy to get to.

How To Check The Fluid in RV Hydraulic Slide Out

If your slide-out is made by Lippert, you should have a white or clear plastic reservoir in plain sight. This design will let you see how much fluid is in the reservoir.

If you do not have a leak anywhere, then the reservoir should always show the same amount of fluid. According to one image, Lippert puts a mark or a label on the outside of their reservoir so you can see exactly where that fluid level should be.

If the fluid is not up to that mark, then you know you need to add more. If it is at the mark do not add any. The last thing you want to do is over-fill the reservoir.

It may be that you will need to clean the side of the reservoir to get a clear view of the level of fluid inside. In this case, the hydraulic fluid reservoir is more like the window washing tank. There is no dipstick just an opaque view of the contents.

It is often the same with the power steering tank as well. You just need to know where the fill line is and stop at that line.

Adding Hydraulic Fluid To RV Slide Out


We are only addressing one system here. There may be variations to the location of the hydraulic fluid tank and how to fill it. In the case mentioned above, all you have to do is have your hydraulic fluid ready and a funnel.

Then open the cap, stick the funnel inside, and pour in enough fluid to reach the fill line. That is all there is to it. There is one more step to do before you start filling the tank.

Make sure the slides are retracted. This helps prevent any overflowing of the system. The key will be to follow the steps outlined in your manual. If you do not have a manual anymore, Lippert and other companies keep libraries now.

You can always get one directly from any of the companies that made your slide-out system. You will get the right brand of fluid to use in those manuals as well.

How To Pour Hydraulic Fluid Into RV Reservoir

Some locations for these reservoirs can make it very tricky to access and pour the fluid inside. One RV owner had to remove his entry steps to get to the leveling jack reservoir.

There is a process to follow for this system beyond just pouring fluid inside. You need to first, add fluid till it is full. Then you need to start your engine, place your jack system on manual, and then lower and retract the front jacks, then repeat that for the rear jacks.

Once you have done that, you need to add more fluid. The manual may tell you to do this process several times to make sure the system is fully lubricated. You may need a funnel and some plastic gloves to keep the dirt off your hands as well as not spill any fluid.

Each RV will have its own method of adding hydraulic fluid depending on the location of the reservoir and which system you are replenishing with fluid.

How To Check Hydraulic Fluid On RV Jacks


In some systems, you just need to look at the reservoir to see that you are low on fluid. The location of the reservoir will make it either easy to see the lack of fluid or very difficult to see it. Make sure to find a position that gives you a clear view.

As we said earlier, the reservoirs for leveling jacks are more of an opaque color to them. The tank is not clear but it is not completely dark so you cannot see. The fluid will show up as black against the opaque coloring of the tank.

All you have to do is see where the dark line ends in relation to where the fill line is at. If it is a short distance then you will not have to add a lot of fluid. But if it is a large distance you may have to add a couple of quarts of fluid.

How To Add Hydraulic Fluid To RV Jacks

The best thing to do is get your manual for your specific leveling jack system and follow those instructions. Because the system is fairly spread out over the underneath area of your RV, you may have to add more fluid than you realize.

Then, to make sure there is enough fluid in the system it is not enough to just go to the fill line. Run your jacks up and down a few times to make sure the fluid is evenly distributed and then add more fluid to the reservoir till you reach that fill line.

This is more of a time-consuming task than a technical one. The amount of fluid you use will depend on the size of the system. It is not like filling your transmission with new fluid, where you just go to the fill line and close the fill cap.

You have to do a few steps to make sure you are not underfilling the system.

How Often Do You Need To Change The Hydraulic Fluid In an RV?


According to some owners, they do not make any changes to the hydraulic fluid. One said that back in 2005 HWH had a time or mileage requirement but by the time he upgraded in 2008 that requirement was gone.

In other words, the number of times you need to change the hydraulic fluid is up to the manufacturer’s recommendation. Some owners have gone 110,000+ miles without changing it.

You will have to make a change if you have a leak, bad seals, etc., but that is not regular maintenance. It is going to be up to you if you want to change it or not. The key would be not to mix fluid if you do not change it.

Finding RV Hydraulic Repair Near Me

The first place to look would be your brand’s dealers’ locations. They are usually spread around the country and may have time to service your RV even if you didn’t buy your RV through them. Call first though.

Then there is this website. It seems to list a variety of RV service centers throughout the country. If you use the subheading above as your search term, then you will find many websites that say ‘best RV repair near me…’ and then give a city name.

Most cities around the country will have RV repair centers. It is just a matter of how close to one of those cities you are.

Some Additional Words

Believe it or not, checking your hydraulic fluid in many cases is merely a matter of looking at the reservoir. When you can’t get a good look at one, there may be a dipstick on the cap to tell you if you need to add more or not.

This is one of the simpler maintenance aspects of owning an RV or trailer. Just make sure to have the right fluid in your storage bins.

Leave a Comment: