Cyclic "cricket" sound when pressing brake pedal

Hey guys, love your show. I’m a devoted listener. I have 2001 Chevy Suburban, 130K miles. Noticed problem about a month ago. When you depress brake pedal there is a subtle cyclic “cricket” or vaccum sound sound lasts about 1/2 second each chirp- 2 chirps together, then about 2 second of pause and repeats. This will happen for about 5 or 6 cycles, then stop even though still applying brakes. Is NOT pad to rotor contact because will continue to hear after car stops moving and pedal is applied. No impact on brake performance (yet!). Problem is intermittent, seems to occur on colder days (40-50 degrees) and often goes away in afternoon.

  1. this forum is not the car guys themselves, but a bunch of car buffs, professional mechanics and retired guys who give free advice.
  2. If you have “power brakes” this is probably, a vacume diaphram assisted brake. A vacume hose from the intake side of your engine assists the piston on the brake master cylinder. If the vacume hose leaks a little, or if the diaphram is leaking a little that could cause this. But if you wnat a more professional opinion, wait a few for one of the top 20 contributors, cause I am just a shade tree kind a guy.

Thanks for the info. I’m going to go out and see if I can ID the vacuum system parts and if there is anything apparent. I’ll post back what I find.

sound is very faint, but there. In fact I have trouble hearing it with my old ears. Have to use my 12 year old son to stick his head next to the brake booster. I let the car sit about 30 minutes while I did some research on Brake Booster troubleshooting. I removed the check valve. When I did air escaped, leading me to believe system is holding a seal? I “checked” the one-way check valve by blowing in both ends. It works properly. Any other ideas?