The question of whether you should try to repair or replace your floor jack is actually a fairly common one for any relatively expensive tool. Even with correct use and routine maintenance, an automotive jack will eventually be in need of repair or replacement.
Hydraulic jacks are pretty basic when you break it down. Each jack has 6 main components:
- Reservoir – holds hydraulic fluid
- Pump – Draws hydraulic fluid on every UP stroke of the handle and then creates pressure on every DOWN stroke.
- Check Valve – Allows pressurized fluid from the down stroke to flow to the master cylinder while “checking” off the return port so the fluid cannot flow back.
- Master Cylinder – Fills with hydraulic fluid.
- Piston – Pushed up or outwards due to the hydraulic fluid that fills the master cylinder.
- Release Valve – Once it’s time to lower the jack and return the piston back to the master cylinder, the release valve is opened to allow the fluid to drain back to the reservoir to start the process again.
For a more detailed explanation of how a floor jack works, click here.
Jack does not fully extend or slowly drifts down – Most likely, there is a small leak somewhere which has caused hydraulic fluid to leak out over time. Depending on the leak, you can simply top off the hydraulic fluid or you may need to repair.
Wheels are squeaky or appear damaged – You may need to lubricate the wheels or possibly replaced the damaged wheel(s). Fortunately, replacement wheels are sold for most major brands and are easy to replace yourself.
Frame is damaged – Jacks may seem indestructible but if you notice the frame is cracked, bent, or noticeable damaged, it’s not safe to use anymore and will need to be replaced (do not attempt to fix).
Oil appears milky or foamy – Somehow, water has made its way into the system and will slowly damage the jack from the inside, eventually beyond repair.
Handle kicks back – If the handle kicks back up after a down stroke, stop using it immediately as this can be very dangerous. This issue may be repaired by a professional.
Repair or Replace?
Typically, this depends on the value of the jack. If you have a $100 jack from Harbor Freight, it would make no sense to take it to a hydraulic jack repair shop which would cost more than a new comparable jack. But the case may be different for higher end brands such as Hein-Werner or Milwaukee.
It’s really a similar argument as when you’re trying to determine whether to replace or resurface brake rotors. Unlike repair manuals for cars, there’s no manual to repair various brands of jacks so getting the pros to help is the only option.
Sometimes buying just the hydraulic unit or other floor jack repair parts and replacing it yourself would make sense. Companies such as Gustin Hydraulics, HCRCnow.com, and others have a wide range of replacement parts. Figuring out how to fix a floor jack is often a matter going to the manufacturer’s site or doing some Googling.