Updated on November 24, 2022
The floor jack or a hydraulic jack and its proper functioning are crucial for any DIY or beginner mechanic. And just like the cars you fix, a hydraulic jack needs some servicing and an occasional repair. So, to avoid or minimize downtime because of faulty equipment, here are some problems you might encounter.
The hydraulic jack’s common problems and solutions include a damaged or bent frame and wheels; the jack doesn’t fully lift or lower; oil leaks, foaming oil, and lastly, the jack won’t lift or lower at all.
So, let us begin with troubleshooting and inspecting the hydraulic jack before moving on to solutions.
Hydraulic Jack Troubleshooting Steps
First and foremost, check the weight rating of your jack and then make sure you know what your car weighs. Of course, the total weight of your car isn’t that important because you are only lifting one axle. However, it’s still very much possible to overload the jack.
But, as a rule of thumb, a two-ton jack will lift virtually any car, no matter the size, and for a large SUV like the Suburban and Tahoe or a full-size truck, a three-ton jack would be ideal. Still, it never hurts to have a stronger car jack than needed, and you should always secure your car with jack stands no matter what.
A visual inspection always goes a long way, and that’s the case with hydraulic jacks too. Look for signs of bending, leaking fluids, cracked weld spots, and broken wheels. Also, look for rust and missing components and note the general condition of the jack.
If you notice the jack frame is bent or cracked, the best solution is to retire the jack and get a new one. However, if you notice leaks, scroll further down to see how you can fix them.
Test the Jack Without a Load
To make sure everything is moving as smoothly as possible, try lifting your jack before you put it under the car. That way, you avoid surprises, and you will find out if it’s functioning correctly and what’s broken.
So, tighten the purge valve and pump the jack until it’s fully extended. The jack should lift about an inch and a half or more with each pump, and if it doesn’t or it takes too long to raise, it’s probably low on oil.
Also, if the jack doesn’t lower after you open the purge valve or it won’t lift to full height, there is likely trapped air in the system, and you need to bleed the system. Lastly, if the jack won’t lift at all, there is likely a massive leak, and all the oil has escaped.
Try Lifting Your Car
If all previous tests are good, it’s time to try and lift your car. Place the jack saddle on your car’s floor at the correct lift spot, close the purge valve, and start lifting. If your jack won’t lift or hold your vehicle up or the handle feels spongy when pumping, again, there is probably air trapped in the system.
There is also a possibility that you manage to lift your car up, but it won’t lower when you open the purge valve, and again, it’s mainly down to air in the system.
Hydraulic Jack Common Problems and Solutions
The frame of a hydraulic jack is possibly its most important component, structurally at least. Since pretty much all hydraulic jacks see abuse and misuse, it’s highly common to see a bent, damaged, or cracked frame.
Now, frame damage is also highly prevalent with low-quality jacks, and you should always feel discouraged from trying to save money on something that can significantly hurt you if it fails.
Also, fixing a hydraulic jack frame isn’t something anyone would recommend. Partly because straightening out the bent components won’t really do much at all because the material integrity has already been compromised.
The same goes for the wheels, which often become useless after a while, but in case they start to bend or crack. Since the car’s weight rests on the wheels, as soon as you notice any damage, it’s time to replace them if it’s possible or buy a new jack.
On the other hand, welding a hydraulic jack can further damage internal components like seals, hydraulic pistons, and lines. Add on top of that the fact that a welded piece of metal will never be the same strength as it used to be, and you are better off replacing your broken jack for a new one by all accounts.
Jack Won’t Fully Extend or Takes Too Long to Lift
Rarely will anyone need to extend their hydraulic jack to lift to full height to lift their car up, and if you do, you are probably better of with a better jack.
However, a slow-lifting jack is a significant problem, especially if you own a business; plus, it’s only a matter of time before it stops working altogether. Now, both conditions result because of low oil or hydraulic fluid. So, the solution is to add more oil and bleed the system properly; here is how.
How to Add Oil to a Hydraulic Jack
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- Prepare your hydraulic oil.
- Locate the oil fill plugs or bolts. These are usually right on top of the manifold where your handlebar piston is located, and there is a metal or plastic cover over them. Also, if you have a smaller jack with a single piston, you will have a rubber plug somewhere halfway down the cylinder.
- Remove the oil fill plug/bolt.
- Lift the jack saddle by hand to its full height and prop it up with something
- Add oil while pumping the lift until you see more air bubbles coming out
- Tighten the bolt or put the rubber plug back in
This video sums it up pretty well, but note that on some jacks, the oil filler hole can be on the main cylinder body.
Jack Won’t Lower or Lift
Usually, when the jack doesn’t fully lower, it’s a sign that there is air trapped in the system. This issue can get you in a significant amount of trouble since it doesn’t show any symptoms until you lift the car up and are unable to lower it. That said, it’s somewhat normal for the jack to catch some air, especially if you often lift it to full height. Also, this same problem can result in a jack that won’t lift at all.
However, if that happens often, it could also be a sign that the jack has a leak somewhere, even if you don’t see wet spots on the frame. That’s most easily noticeable when you open the oil fill plug and see the hydraulic fluid inside is foamy. But more on that later for now; let’s see how to bleed the hydraulic jack.
How to Bleed a Hydraulic Lift
- Remove the plastic or metal cover just in front of the handlebar
- Once that’s off, find the oil filler bolt or plug and make sure it’s tight
- Now, open the purge valve or rotate the handle counterclockwise like you would do to lower the car.
- Then, while the purge valve is open, start pumping the handle and do it about 15 to 20 times.
- Unfasten the oil filler bolt to release the air and tighten it again
- Tighten the purge valve and see if your lift works properly. If not, repeat the same process until all air is removed from the system.
A short video that is straight to the point.
Oil Leaks and Foaming Oil
Oil leaks and foaming oil are two very different symptoms; however, they share the same common cause: failed seals or O-Rings. Now, oil leaks will lead to a slow-lifting jack, and one that won’t fully extend, while foaming oil, or better said, vacuum leaks, will lead to a jack that won’t lift at all or one you can’t lower.
These subjects are already covered, and as we mentioned, it’s expected that the system draws some air or loses some oil. But, if that happens often, and you either notice a visible oil leak oil or don’t, it’s a good idea to replace the O-ring piston seal. The same goes for foaming oil, but that can also happen if your oil fill plug isn’t sealing correctly, so you might want to replace that one as well.
How to Replace a Hydraulic Jack O-Ring Seal
- Remove the plastic or metal cover in front of the handlebar
- Disconnect the loading spring that’s on the handlebar socket with a screwdriver
- Remove the safety pin on the handlebar socket pivot point with pliers. Now, remove the central pin that the handlebar socket pivots around
- There is one more pivot point between the handlebar socket and the jack piston, and you can remove it the same way as the previous one.
- Now you can simply pull the jack piston out, and you will notice an O-ring at the tip, and sometimes there is another one near the top. There are standard-size O-rings that you can buy anywhere.
- Remove both O-rings with a flat screwdriver and install new ones.
- Assemble everything back in reverse order
- Use the previous guides to bleed the air out of the system or to add hydraulic oil.
The process might vary slightly between hydraulic jack models, but it will be more similar than different.
What Fluid Is Used in a Hydraulic Jack?
All hydraulic jacks use hydraulic jack oil, specifically ISO VG 32 mineral oil. But it’s best to buy hydraulic oil that says “jack oil” or “hydraulic jack oil” on the label to avoid any mistakes.
Will Brake Fluid Work in a Hydraulic Jack?
No, brake fluid will not work in a hydraulic jack. Technically it will but only for a short time before your hydraulic jack is ready for the scrap yard. Brake oil is way too abrasive for jack rubber seals, and some of them are impossible to replace.
What Are the Three Types of Jacks?
The three main types of mobile jacks used in the automotive industry are the scissor jack, floor jack, and bottle jack. The floor jack is used in car repair shops and by a bit more serious DIYers. A scissor jack is a type most cars get as standard equipment in the trunk. And lastly, the bottle jacks are mainly used for special work and special vehicles like heavy-duty trucks.
How Long Can a Floor Jack Hold a Car?
How long a floor jack will hold a car depends on the jack and the car. But even in the best-case scenario, you can expect the jack to hold a car up for half an hour before it starts lowering.
How Strong of a Car Jack Do I Need?
You can mostly get away with a car jack with a much lower weight capacity than your car weighs. But to be on the safe side, you can use a 1-1.5 ton jack on compact cars and hatchbacks. For medium-sized to large sedans, a 1.5.2 ton is ideal. And for heavy SUVs and trucks, a 2-3 ton jacks should be fine, but pay attention to the maximum lift height in this case.
What Is the Easiest Car Jack to Use?
The easiest car jack to use is the floor jack because there is the least room for operating error. The second easiest is the bottle jack because it’s not as stable as a floor jack. And the hardest jack to use, or the most dangerous one, is the scissor jack because it’s the most unstable one, easiest to bend, and the car can slide off it the easiest.
What Are the Dangers of Using a Hydraulic Jack?
The number one thing you should be careful about when using a car jack is that the car is on level ground. But here is a full list of things you should be careful about.
- Make sure to check your manual to see where the jack points on your car floor are. If you lift the car with the jack in the wrong spot, the car floor can collapse.
- Always see that the car is on level ground. Otherwise, it can slide off the car jack.
- Ensure the car jack has enough lift capacity to lift your car.
- Make sure to check your tire or pull the hand brake so the car doesn’t start moving while it’s in the air.
Will Engine Oil Hurt a Hydraulic Jack?
Yes, the engine oil will hurt a hydraulic jack. Engine oil has a slew of different additives that are unnecessary for a hydraulic jack and harmful. For example, engine oil has different detergents that will foam up when they get in contact with water and consequently cause different issues with how the jack works.
In the end, a hydraulic jack is a fairly straightforward mechanism making it easy to both troubleshoot and repair. To put it in simple terms, the first troubleshooting step you should make is to try and lift the jack without any weight on it. If all works well, try and lift a car with it.
If the hydraulic jack is faulty, you might notice that it won’t fully extend or takes a long time to do so. In that case, you want to add oil.
Moving further, if you notice oil leaks or foaming oil, you want to replace the hydraulic piston O-Ring seal. A car jack that won’t lower once you lift a car has air in the hydraulic system, and you have to bleed it.
If you encounter any of these issues, they are pretty straightforward to repair by using our guides or looking at the videos we found. And lastly, if you notice any frame damage, be it that it’s bent or you see some cracking welds, the best thing you can do is replace the jack.
Here are some more articles for you to check out:
Do All Cars Come With A Jack?
Bottle Jack vs Floor Jack: What Are The Differences?
How to Use a Floor Jack to Lift a Car