Hydraulic fluid is the bread and butter for machines that use hydraulic power. It serves as a medium for transferring power in hydraulic systems. Moreover, the fluid lubricates moving parts and helps prevent damage and leaks.
The fluid is known for its low viscosity and non-compressible nature. Unlike many other fluids used in hydraulic systems, hydraulic fluid is usually costly. If your car, tractor, mower, or construction machine runs out of this fluid, you might get tempted to use an alternative.
So, what can you use as a hydraulic fluid substitute?
Herein we discuss six products you can use as substitutes for hydraulic fluid. We’ll also provide the merits and demerits of using these products.
Answer: Substitute for Hydraulic Fluid
The six substitutes for hydraulic fluid are:
- Engine oil
- Automatic transmission fluid (ATF)
- Brake fluid
- Power steering fluid
- Vegetable seed oil
- Water
Engine Oil
Engine oil is a readily available alternative to hydraulic fluid. You can find it in local garages and workshops. While it’s not a recommended alternative, you can use engine oil in emergencies.
If you want to use engine oil as an alternative to hydraulic fluid, choose a variety with a low API rating. The most common engine oils used as alternatives to hydraulic fluid are Engine Oil SAE 10, Engine Oil SAE 20, and Engine Oil SAE 30.
If you’re looking for engine oil for light or heavy-duty equipment, go for the Engine Oil SAE 10. This oil will prevent corrosion, wearing, and foam formation.
Engine oil comes with a higher viscosity and density than other fluids. It can cause poor performance and damage the hydraulic system. If you want to prevent damage to the system, mix the oil with some regular hydraulic fluid. Doing so reduces its viscosity.
Engine oil can be helpful when you don’t have access to hydraulic fluid. So, add just enough oil to get the job done. You can change the oil after buying hydraulic fluid.
Pros
- Readily available
- Lubricates moving parts effectively in hot conditions
- Inhibits rust and corrosion
Cons
- Its high viscosity can cause damage to the hydraulic system.
- Most engine oils contain additives for removing deposits in the engine. These additives can wear away the seals in the hydraulic system.
Automatic Transmission Fluid
Automatic transmission fluid (ATF) is the most popular alternative to hydraulic fluid. And like engine oils, ATF is readily available in local garages and workshops.
Consider an option with the correct viscosity when using automatic transmission fluid as a hydraulic fluid substitute. You can contact a professional mechanic to know the type of ATF that suits your machine.
While ATF is the primary fluid in some cars’ hydraulic systems, it can cause several issues. ATF has additives that usually damage the hydraulic seals. The fluid is also known to foam when you subject it to extremely high pressure. That’s unlike hydraulic fluids, which don’t foam under high pressure.
The cylinders in your machine’s hydraulic systems can be a reason to reconsider using ATF. Some of these cylinders function effectively with specific hydraulic fluids. The cylinders won’t be effective if you use ATF instead of the recommended fluid.
Often, hydraulic jack owners swear by ATFs as excellent alternatives to hydraulic jack fluids.
Pros
- Affordable
- Readily available
Cons
- ATF contains additives that can damage hydraulic seals
- It foams easily under high pressure
- It can cause poor performance in some cylinders
Brake Fluid
Brake fluid is another substitute for hydraulic fluid in cars and motorcycles. It has many similarities with hydraulic fluid. However, you’ll want to use brake fluid as a hydraulic fluid alternative in emergencies.
The alcohol in brake fluid can cause damage to seals in hydraulic systems. Unlike hydraulic oils, brake fluids lack anti-wear and anti-foam additives. When used under high pressure, this fluid won’t protect parts from wear or foam formation.
Brake fluids work best in hydraulic braking systems. They contain Polyalkylene glycol that ensures optimum performance and longevity for braking systems.
So, if you’re driving or riding and your car or motorcycle runs out of hydraulic fluid, you can use brake fluid.
Use just enough brake fluid to get you to your home or the next workshop. After buying the recommended hydraulic fluid, drain the brake fluid in the system before refilling the reservoir.
Pros
- Affordable
- Readily available
- Boosts the brake system’s performance and lifespan
Cons
- It can cause damage to the seals
- It lacks essential additives for protecting hydraulic systems from wear and foam formation
Power Steering Fluid
Modern cars, trucks, and SUVs use power steering fluid (PSF) to ensure the smooth operation of power steering systems. But can you use PSF as a substitute for hydraulic fluid?
The truth is that you can use PSF as an alternative to hydraulic fluid. Like hydraulic fluid, power steering fluid transfers power efficiently. It can also be effective when used under extreme pressure. The fluid consists of corrosion inhibitors and antifoam agents.
However, use this fluid in emergencies before accessing the recommended hydraulic fluid.
PSF has additives that help reduce wear in the steering system. These additives can damage rubber seals in the system. If used for an extended period, the seals can start leaking oil.
PSF has a lower viscosity than most hydraulic fluids. It can result in poor performance in hydraulic systems that require fluids with higher viscosities.
Pros
- It’s effective when used in extreme pressure
- It transfers power efficiently in the hydraulic system
- It consists of corrosion inhibitors and antifoam agents
Cons
- It has additives that can wear out rubber seals
- It has a lower viscosity than most hydraulic fluids
Vegetable Seed Oil
Vegetable seed oil is another hydraulic fluid substitute in your car’s hydraulic system. These oils effectively lubricate metal parts and efficiently transfer power in hydraulic systems.
Some of the reasons you’ll want to use vegetable oils over mineral oils in your hydraulic system are:
- They’re biodegradable
- They’re non-toxic
- They have high lubricity
- They have higher flashpoints of up to 3200C
If you’re looking for effective vegetable seed oil, choose those extracted from soy, sunflower, and canola seeds.
You should note that this oil will be effective depending on the base oil type and additives used.
Unfortunately, vegetable seed oils have low oxidation resistance. As a result, the oils can degrade and break down faster, reducing the system’s performance.
These oils are expensive and don’t perform well in low temperatures.
Pros
- High lubricity
- Biodegradable
- Non-toxic
- High flashpoint
Cons
- Expensive
- Low oxidation resistance
- Not ideal for low-temperature use
Water
Water is a good alternative to hydraulic fluid, particularly in low-pressure applications. However, use water if you don’t have access to hydraulic fluid.
Water performs poorly in some hydraulic systems. It can quickly freeze and prevent the system from functioning well. If you want good results, your water should be clean and debris-free. Additionally, use the clutch pedal or brakes more often to prevent water from freezing.
Water is highly corrosive and can damage parts of the hydraulic system. Thankfully, you can reduce the corrosive effects of water by adding some antifreeze.
This liquid lacks the lubrication properties found in hydraulic fluids. So, moving parts can wear out, overheat and succumb to irreversible damage.
Pros
- Readily available
- Non-toxic in the case of leaks
Cons
- Water freezes quickly, forming ice in relatively low temperatures
- Provides little lubrication
- It can cause corrosion in the system
- Boils and overheats the system at high temperatures
Final Thoughts
Several alternatives to hydraulic oil are available to keep your machines running. They include engine oil, automatic transmission fluid, brake fluid, vegetable seed oil, power steering fluid, and water.
Whether cars, tractors, trucks, mowers, UTVs, or construction equipment, these alternatives will save the day before you can access the recommended fluid.
Consider the cons & pros before choosing a hydraulic fluid substitute. Avoid using these alternatives for an extended period as they can damage various hydraulic system parts.