Master Cylinder Noise

[motags]

There is a thread of this same problem from 2009 without the specifics I've provided. The conclusion was simply accepting that the cylinder has a motorized function which has its benefits. However I feel my situation is a little abnormal and would like some input.

I just bought a cream puff of an 01' SR5.

I noticed a motorized noise where the Master Cylinder is.

1. It happens specifically when the brake pedal has been pressed 5 or 6 times
while driving or stopped.
2. The motorized noise is right where the master cylinder sits beyond the
firewall, lasts for 5 or 6 seconds and clicks off somewhere down near the
passenger side firewall.
3. Filled up reservoir (which was a little low) to max. After a couple days of
driving, brake fluid is now noticeably above max about 1/8 of an inch.

I understand that this feature is motorized and has its benefits but would rather not hear it go off every 5th or 6th brake application without fail. I doubt engineers had that happening as often in mind. Any suggestions? Thanks

 

[nevada]

There is a thread of this same problem from 2009 without the specifics I've provided. The conclusion was simply accepting that the cylinder has a motorized function which has its benefits. However I feel my situation is a little abnormal and would like some input.

I just bought a cream puff of an 01' SR5.

I noticed a motorized noise where the Master Cylinder is.

1. It happens specifically when the brake pedal has been pressed 5 or 6 times
while driving or stopped.
2. The motorized noise is right where the master cylinder sits beyond the
firewall, lasts for 5 or 6 seconds and clicks off somewhere down near the
passenger side firewall.
3. Filled up reservoir (which was a little low) to max. After a couple days of
driving, brake fluid is now noticeably above max about 1/8 of an inch.

I understand that this feature is motorized and has its benefits but would rather not hear it go off every 5th or 6th brake application without fail. I doubt engineers had that happening as often in mind. Any suggestions? Thanks

you say 01, but my system shows a vacuum assist for 01, yet a hydraulic combo unit for 02. either way...

if you have the combo unit, it sounds like its working properly. with that system, you get brake assist via pressurized brake fluid. repeatedly pumping the pedal depletes that pressure. the noise you hear is the pump re-pressurizing the system. in short, it is doing as its designed.


that said, perhaps something is failing, if the noise is louder than it should be, or the pump is running more often. possibly an internal leak, draining off some pressure over time. but, if it only does it after you pump the pedal, I think its probably fine...

 

[motags]

You're right, it is the pressurized brake assist system. Should have stated that.
However, I wrote that it goes off after 5 or 6 applications, stopped or driving.

What I meant to say was while I'm driving and come to stop signs or lights or just slowing down, I notice that the noise occurs after every 5th or 6th application no matter the scenario. I think that's too often and will likely happen 3 or 4 times in a 15 minute ride through a couple towns.

I'm going to check the unit to see if it does indeed have a link.

Nevada, thanks for the input.