Russell Brake Bleeders and question about humming sound.

[ridewhencan]

First time bleeding the brakes and put in Russell Speed Bleeders. I remembered the part about not pushing the pedal to the floor and after the first 2 or 3 slow pushes, I put a piece of 2by4 behind the pedal to insure not going too far. But most times pushing the pedal towards the end of the travel, I started to hear a hum coming from the back of the car. Caliper? Brake booser? You can hear it at 10 sec and 27 sec of the following video:

The sound is obscured a little by the tinkling sound since I didn't have the hose submerged.

Hose is submerged in this vid (but no hum) which I'm including just because you can see that the bleeder check valve is working. (Should have used more light.)

 

[ridewhencan]

Hmm, so wheels are back on the car and it drives fine. Nice firm pedal. Still curious about that slight humming sound towards the end of the brake pedal travel when bleeding (with 2x4 under it.). Pretty sure it's not the brake booster since the sound came from the rear. No one else hears a sound when bleeding? Must have imagined it, lol.

 

[NSXGB]

Had similar sound with my speed bleeders. I think they have a ball bearing and spring type mechanism which resonates as the fluid passes around it. Perfectly normal IMHO.

 

[Valhalla]

Had similar sound with my speed bleeders. I think they have a ball bearing and spring type mechanism which resonates as the fluid passes around it. Perfectly normal IMHO.

That is exactly the case. I noticed this too the first time I installed these bleeders.

 

[ridewhencan]

That is exactly the case. I noticed this too the first time I installed these bleeders.

Makes good sense. Bless you guys. So I'm not more crazy than I thought I was. Bleeders make good sense. Checked them after a hard drive and no seepage.