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How To Repair A Floor Jack That Won’t Hold Pressure: Step-by-Step Guide

Few tools are as useful as a floor jack. There’s nothing else you can use for lifting a vehicle as quickly and comfortably. So it eventually becomes an essential tool for any mechanic or car enthusiast.

When it starts to lose pressure on the job, problems follow. You waste time, effort, or sometimes just lose the chance to fix your car by yourself.

And all of that can be extremely frustrating.

But don’t worry. Most floor jack issues are fixable. That’s why we will teach you how to repair a floor jack that won’t hold pressure in this article.

You’re going to learn the ups and downs of floor jacks, as well as the best ways to check and repair as needed.

Even if your floor jack has no problem with pressure, you’ll learn how to maintain the piece like a professional.

So, want to know everything we have for you? Then keep scrolling!

For different lifting purposes, you can check the review of the best electric tongue jack.

What is a Floor Jack?

Before we go any further, it is crucial to understand what a floor jack is in the first place.

Obviously, it is a device to lift vehicles. But how is a floor jack different from other tools to lift cars.

Well, there are three types of floor jacks to consider. You can find the mechanical floor jack and the hydraulic floor jack, the two most popular.

There’s also the pneumatic jack, which is less popular but still worth mentioning.

Below is a little more about each:

Mechanical

Instead of using a liquid that gets tougher with pressure, mechanical jacks use a typical lifting mechanism made with high-quality materials.

The focus is to lift the weight by operating the tool manually. These floor jacks, however, don’t use pressure.

Pneumatic

Lastly, you have the pneumatic floor jack that produces strength by using compressed air. For this kind of jack, you will need a compressor.

They can achieve incredible strength and lift hefty weights as well. But they don’t use pressure.

Hydraulic

Lastly, you’ll find the hydraulic jack. It uses a special liquid called hydraulic oil. Some people also call it jacking oil.

Either way, this liquid has a unique composition that increases the tool’s strength when some pressure is applied.

The more pressure is applied to the liquid, the more strength you get from the jack.

This is the type of floor jack we’re going to teach you how to fix today: the hydraulic model.

How Does a Hydraulic Jack Work?

So, you already have an idea of how a hydraulic jack operates. But we haven’t gotten into the nitty-gritty yet.

To give you a clearer idea, the hydraulic jack works like a pump internally.

The handle of the jack, for example, works as the pump. When you lift this handle, a pump plunger pushes the hydraulic oil into the cylinder via a discharge valve.

When the cylinder starts to fill up with oil, it generates pressure.

The more you move the handle up and down, the more oil goes into the cylinder, so the more pressure is created.

In most jacks, the more pressure pumped, the more the jack goes up. So that’s why you usually need to pump the jack to lift a car.

If this wasn’t clear, you could check this video to have a better idea:

Why Won’t My Hydraulic Jack Hold Pressure?

Understand how the hydraulic jack works? If you do, then it’s time to know why the hydraulic jack does not hold the weight.

Below are a few reasons to consider:

Overloading

Many people don’t understand that even if you have the biggest hydraulic jack, the tool has a limit. You can’t lift 5 tons with a small jack, for example.

That’s why it is common to find hydraulic jacks holding no pressure. They just can’t hold as much weight, so the whole system fails to build the pressure up.

In some cases, the jack may lift the vehicle a little. But at one point, it succumbs to the weight by releasing the pressure forcefully.

This is a clear sign you’re overloading the jack.

Either way, it is super dangerous. Overloading a jack may end up in grave damage to you or the vehicle itself.

So before using the hydraulic jack, check its weight limit and make sure the vehicle you’re lifting is below that level.

Not Enough / Too Much Oil

If the hydraulic jack doesn’t have proper oil levels, there’s a high chance it won’t work as it should.

When the oil levels are too low, the pressure won’t build up for a lack of liquid.

Because the liquid is what causes the pressure, lack of liquid means less pressure. If there’s too little pressure, you may not even build any pressure at all.

When there’s too much oil, the pressure builds up but doesn’t hold. This usually causes a leak.

With so much pressure, the system automatically releases pressure, generally preventing the jack from holding it.

In some cases, too much oil may cause permanent damage on rings and seals, demanding replacement eventually.

Loosen Valve

An old floor jack pressure relief valve may also be the cause of the tool not holding pressure.

When the valve is broken, worn out, or just badly positioned, the pressure will automatically release from the oil reservoir.

No matter how much you pump the jack, the pressure just won’t hold.

Broken Plug

The cylinder plug keeps the hydraulic fluid inside the jack, preventing any leak from keeping the pressure working.

When it breaks or loosens up, the hydraulic jack loses pressure, so it will either don’t lift the vehicle or eventually don’t stay with the pressure up as needed.

Lack of Maintenance

Lastly, there’s a high chance you’re just looking at a floor jack with little lubrication, too much rust, or simply damaged pieces (seals, rings, plunger, etc.) that need some change.

Even small damage on a wheel or hinge may eventually cause a stability problem that prevents the jack from holding pressure.

So keeping the jack working pristinely is also essential.

Step-By-Step: How to Repair a Floor Jack with no Pressure

You’ve gone through all the typical reasons a floor jack is not holding pressure. Now let’s explain how you can fix it.

Here are a few steps to consider:

01. Clean Thoroughly

Whatever may be happening to the floor jack, we recommend starting by cleaning it.

This will eliminate debris, gunk, and any other impurity that may eventually affect the fixing process.

Use a hard-brittle brush, a rag, and a metal cleaner for this.

The focus is to remove as much filth as possible so you can work with the hydraulic jack more easily later.

In some cases, you may discover that the filth was the thing causing the problem. You may not even need to keep fixing after cleaning.

02. Remove the Cylinder Plug

If you already cleaned the jack, then you’re ready to test the cylinder plug.

First, you need to look for it. This piece is usually made of black rubber. And it is located on top of the cylinder that pushes the fluid.

Once you find it, check that it is not broken or loosened up. If there’s a problem with the piece, use a screwdriver or similar tool to pry it out. Otherwise, it should come right off with a pull.

03. Drain & Replace the Fluid

Once you’ve removed the cylinder plug and put it back, you may want to test the jack again.

If it doesn’t work, then it is probably time to change the hydraulic fluid.

First, check that the fluid is not dirty or has gunk. Even some debris on the fluid chamber may cause the fluid to not work correctly.

Another reason may be that you have too little fluid or too much, as said before.

Either way, we recommend draining the cylinder completely. Just take the plug out and put the jack upside down on top of a bucket. Let all the oil go out.

Now you can check the fluid level. If you see too much (check the jack’s ideal hydraulic fluid levels), then pour only the right amount back into the tool.

Otherwise, add some more oil and fill the jack.

If the fluid is too dirty (gunky), then replace it entirely. Be sure to add just enough oil for the jack to start working correctly.

04. Check the Rubber Plug

Now put the rubber plug back on. If it is broken or damaged, then look for a new one. A rubber plug is generally cheap.

Before putting it on, be sure to clean it thoroughly. Put it back on the right hole and then press it firmly. The plug should fit flat on the hole.

Now you should test the jack once again. If it doesn’t work correctly, then you may be looking at a release valve problem.

05. Check Release Valve

If you already went through the previous steps, but the problem seems to persist, then you may be looking at some floor jack pressure release problems.

The release valve may be releasing too much pressure when you’re lifting.

This may happen because there’s too much fluid on the jack, so it releases pressure automatically.

But in most cases, it happens that the release valve is broken or faulty. Either way, it is generally safe to take it off and check it.

In case it is damaged, replace it. Otherwise, just put it back again.

If the valve is fitting too loosely in place, then there’s a high chance of leaking pressure.

By removing it and putting it on again, you may fix the tightening problem.

This could fix the problem once and for all. But it may not. In that case, you may be looking at an air issue.

06. Bleed the Jack

After draining the hydraulic fluid and replacing the rubber plug, you may have let some air go into the jack. This may also cause a loss of pressure.

To fix it, you just need to bleed it out. This process consists of retracting the release valve and then pump the handle several times.

Any air inside the jack will go out this way.

Then you can place the release valve back in normal position and see if it works. Screw the handle in and pump. The valve should have no problem.

07. Test the Jack

Before you go and lift any car with the jack after following our steps, test it out first.

We recommend lifting the arm and then bring it down several times. This should let you know if the problem persists.

If after several tries you still see no problem, test it with a vehicle.

Lift a car a few inches and see if the jack holds. Then slowly go up and see if the jack loses no pressure in the process.

Let the jack do the same for about 5 minutes. If you see no problem with the jack, then it is probably safe to start using it as necessary.

How To Repair A Floor Jack That Won’t Hold Pressure: (FAQ’s)

Still, have doubts regarding floor jack pressure repairs? Don’t worry, you may find the answer to that doubt below:

What fluid do you need for a hydraulic jack?

You will need hydraulic oil or fluid for the job. This type of fluid is generally made of 99% mineral oil with 1% additives.

You will find it on most auto and tool shops by this name. We think the Gunk Store Liquid Wrench Oil is a perfect option. It is specifically designed for hydraulic jacks.

Can I use brake fluid on my hydraulic jack?

No. Brake fluid may look similar and provide a similar advantage, but it is not wise to use it on your jack because of its acidity.

It is likely to damage the seals and rubbers that prevent the jacking oil from getting out.

So the oil will not only prevent the jack from working well, it will leak eventually as well.

What is a hydraulic jack made of?

It depends on the model you have. But generally, they are made of heavy-gauge steel.

That’s the only material that can handle the many tons of weight that a vehicle has. Some of the parts are either made of rubber or plastic.

But these parts are generally not involved in the weight-lifting process of the jack.

Conclusion

So, do you already have an idea on how to repair a floor jack that won’t hold pressure? We hope you learned a thing or two.

Fixing a hydraulic jack with this problem won’t be easy, though. So we recommend taking every step with care and following all our recommendations to the letter.

Then, you’ll be able to fix that floor jack perfectly.

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