Translation guide
A liquid used to transmit power in hydraulic machinery. In Japanese, the most common term is 作動油, but other compounds exist depending on context.
The standard term for hydraulic fluid used in industrial and mechanical contexts.
The most common and general term for hydraulic fluid. Used in machinery, construction equipment, and industrial applications.
Specifically for hydraulic brake systems in vehicles.
The standard term for brake fluid. Note that this is a specific type of hydraulic fluid.
ブレーキフルードを補充してください。
Please top up the brake fluid.
A slightly more formal or written term for brake fluid.
Specialized term used in aviation.
Specifically 'aircraft hydraulic fluid'. Used in technical aviation contexts.
航空機用作動油は高温に耐える必要がある。
Aircraft hydraulic fluid must withstand high temperatures.
作動油 specifically refers to hydraulic fluid. Do not use it for engine oil (エンジンオイル) or transmission fluid (トランスミッションフルード).
この機械は作動油が必要です。
This machine needs hydraulic fluid.
Literally 'oil-pressure working oil'. A more technical term, often used in engineering specifications.
油圧作動油の交換時期です。
It's time to change the hydraulic fluid.
A common term in automotive and light machinery contexts, using the loanword オイル.
油圧オイルが漏れています。
The hydraulic fluid is leaking.
ブレーキ液の量を確認する。
Check the brake fluid level.