The problem with my Toyota Cressida is that when i Brake or retard my car there is a hissing noise around my Steering. Soon as i leave the Brake paddle sound goes and then again. I checked the Brake fluid and still i input some but the problem is the same. When i showed to my Mechanic he said there is one servo inside the bonet which regulates the fluid, which is damaged. Is that true?? Pleasee help me with honest answers!
Sounds are difficult to diagnose without hearing them first hand.
The brake master cylinder sends brake fluid to the brake calipers when the brake pedal is depressed.
If the master cylinder is leaking, there would probably be a loss in stopping power so it should be repaired as soon as possible.
Another possible source of the sound is a vacuum leak in the power brake booster. A leaking booster would probably cause an increase in pedal effort required to stop the car.
If the master cylinder or booster is leaking, I recommend that you have the problem fixed before driving the car again.
Check the large hose for any breaks or cracks causing leaking from the engine to the brake vacuum servo (power brake assist), and the servo itself. Check the servo with a vacuum pump and observe if it is leaking (will not hold a vacuum), in that case you will have to replace the entire brake servo. The brake master cylinder regulates brake fluid, the brake vacuum servo helps apply the brakes with less effort required by the driver.
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