— An Acura ILX master cylinder recall involves more than 70,000 vehicles to replace the brake master cylinders.
Model year 2016-2020 Acura ILX vehicles may contain contaminated brake fluid that deforms the seals inside the master cylinders.
This can lead to an internal brake fluid leak, a soft brake pedal and a loss of braking.
According to Acura:
"Residual plasticizer in the brake reservoir hose can contaminate the brake fluid, causing the brake master cylinder secondary cup seal to swell and deform. Radiant engine heat further expands the seal, reducing its ability to seal and allowing brake fluid to bypass the seal during slow brake-pedal applications."
Acura says the first complaint possibly related to the problem may have been received 10 years ago when an ILX lost brake pedal pressure. More complaints were received six years later in 2021 but Acura was unable to confirm the loss in brake pedal pressure.
In 2022 the investigation focused on the primary cup seal in the ILX master cylinder but engineers couldn't recreate the symptom.
As of December 5, 2025, Honda had received 192 warranty claims but no reports of injuries or deaths in the past 10 years.
The Acura ILX master cylinders will eventually be replaced, and interim recall letters will be mailed at the beginning of February 2026. However, there is no date when second master cylinder recall letters will be mailed because dealers must first be supplied with more than 70,000 Acura ILX master cylinders.
Acura ILX owners with concerns should call 888-234-2138 and ask about master cylinder recall number RN5.
