Please identify sound coming from brake pedal (2 Viewers)

[kickboxr99]

Well, it's been a long couple months with my LC - essentially ended up having my entire brake master cylinder replaced by Toyota. Anyhow, since picking it up, it has been making a 'pssssshhhh' sound each time I press the brake pedal - almost sounds like a hissing noise.
I returned it to Toyota for them to remedy, and they are stating it is normal. The problem is that it wasn't making the noise when I originally dropped it off, and I can hear it over my radio; thus, I insist it is not normal. The brakes have been bled a number of times by now I'm sure so any other ideas?

Thanks!

 

[agaisin]

Just taking a stab in the dark here, but from looking at the brake system's troubleshooting section of the FSM, their are two noise symptoms:
1) noise from hydraulic brake booster (abnormal pump motor operation noise) which is described as being caused by accumulator bracket clearance out of adjustment. Not sure if that is relevant or not. Is your noise abnormal or just normal brake booster noise but the abnormal part is that you hear it and you don't think you should hear it? Don't understand well enough myself, just trying to provide additional info from FSM to help you in your search.

2) noise from brakes (mechanical noise like cracked/distorted pad, loose installation bolt, scored disc, loose pad support plate, worn sliding pin, dirty pad, glazed pad, faulty tension or return spring, damaged anti-squeal shim, damaged shoe hold-down spring)

 

[hkeller]

I think this is normal. Ours has always done it. So have a few others I've driven to compare it to.

 

[kickboxr99]

Just taking a stab in the dark here, but from looking at the brake system's troubleshooting section of the FSM, their are two noise symptoms:
1) noise from hydraulic brake booster (abnormal pump motor operation noise) which is described as being caused by accumulator bracket clearance out of adjustment. Not sure if that is relevant or not. Is your noise abnormal or just normal brake booster noise but the abnormal part is that you hear it and you don't think you should hear it? Don't understand well enough myself, just trying to provide additional info from FSM to help you in your search.

2) noise from brakes (mechanical noise like cracked/distorted pad, loose installation bolt, scored disc, loose pad support plate, worn sliding pin, dirty pad, glazed pad, faulty tension or return spring, damaged anti-squeal shim, damaged shoe hold-down spring)

Thanks for the ideas...to me it sounds abnormal as it didn't make the sound before the replacement of the master cylinder, and subsequent bleeding of the brakes. Not to mention, I had an '02 that did not make the sound either.

In an effort to better describe the sound, it sounds a lot like air escaping (a hissing sound) when I press the brake pedal.

 

[jgray]

I've not experienced this issue my 100 Series but in my old FJ40 I had the same issue you are describing and it was a brake booster issue.

 

[richg]

Our 98 has done it since our purchase of it 6 years ago. And the 2005 that my in-laws just purchased does it as well.

rich