Defect
On certain vehicles, a seal in the brake master cylinder may be susceptible to damage which can result in a leak if certain conditions exist. The polymer content affects the amount of lubrication the brake fluid provides to brake system components that are exposed to brake fluid. If the brake fluid is replaced with a low polymer brake fluid, and the brake fluid is subsequently subjected to a manual brake fluid bleeding procedure, as opposed to an automated brake bleed procedure, it is possible for the seal at the end of the brake master cylinder primary circuit to become twisted within its retention groove. If this seal becomes twisted, it can result in a leak of a small amount of brake fluid each time the brake pedal is applied. Should a leak occur, after some time the driver will be alerted by the illumination of the low brake fluid indicator light on the meter panel before any effect on braking performance results. If the driver continues to drive the vehicle without refilling the brake fluid reservoir, the vehicle will eventually exhibit a soft or spongy brake pedal feel, requiring more stroke to achieve equivalent braking force. Eventually, if this continues un-remedied, braking performance will be affected, and will finally result in a low pedal and a loss of one braking circuit.
Safety Risk
No risk description available.
Remedy
Dealers will replace the brake master cylinder seal cup and the master power assembly if brake fluid has leaked.