Bleeding brake help. hissing noise

[Spyshot]

2016 v6 3.7l
Replacing all fluid with castrol SRF. Three wheels went fine. on the last wheel, when I opened the bleeder, I hear this hissing noise.
Any assistance would be appreciated. I have gone through a lot of fluid and not getting any air. I did get a lot of air at the beginning of this wheel. I don't think I let the reservoir get too low.
Here is a video...



Thank you

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[Spyshot]

Update: it was only happening on the left rear wheel. Now it’s happening on the right rear wheel as well.

 

[Spyshot]

Update: When my 14yr old is in the driver seat pressing the brake pedal it happens on both rear wheels. When my 12yr old is in the driver seat, it doesn't happen at all...is it possible that my big bury 14yr old is pressing the pedal harder or too hard?

 

[kz]

Are you following the right sequence ? Rear right, rear left, front right and front left ?

 

[NGOT8R]

How are you conducting the bleeding (vacuum pump or pumping the brake pedal)?

 

[NGOT8R]

Gravity bleeding works best for me. I used to use a Mighty Vac many years ago, but for me, I think the gravity bleeding works best. If you‘ve made a mistake and let your reservoir get low and it sucked air, then you might have to take it to the dealer and have them bled.

You mentioned that you’ve used a lot of fluid, which isn’t a bad thing. Whenever I bleed my brakes and clutch system, I always use an entire 32oz bottle to make sure we get a good bleed.

 

[17MagMetal]

Update: When my 14yr old is in the driver seat pressing the brake pedal it happens on both rear wheels. When my 12yr old is in the driver seat, it doesn't happen at all...is it possible that my big bury 14yr old is pressing the pedal harder or too hard?

I’d be worried they pumped the brakes with bleeder open, pulling in air.

try a full flush again, if you can fix it - great. If not, but brakes are still “good”, drive to a dealer and get a full bleed that includes the ABS. If brake feel/confidence is gone, tow it in. The few hundred is worth preventing an accident!

edit: now that i’m thinking about it, that might also be normal hydraulic noises. If your reservoir never emptied itself you might just be worrying too much!

 

[WItoTX]

Where is the hissing actually coming from? The bleeder itself?

 

[GTP]

Sounds like the seat cooler was running, lol.

 

[DrZed]

Not to hijack but is this a dedicated track car? My understanding is that SRF is not hygroscopic at all, meaning any moisture that will get into the system will not be absorbed by the fluid and could create air bubbles, leading to issues.

My understanding is SRF is recommended track only because of this. There are really good street fluids that will absorb moisture and provide good performance (ATE, RBF etc...).

I know this doesn't solve your issue but thought I'd mention. Somebody with more knowledge can clarify this...?

 

[17MagMetal]

Not to hijack but is this a dedicated track car? My understanding is that SRF is not hygroscopic at all, meaning any moisture that will get into the system will not be absorbed by the fluid and could create air bubbles, leading to issues.

My understanding is SRF is recommended track only because of this. There are really good street fluids that will absorb moisture and provide good performance (ATE, RBF etc...).

I know this doesn't solve your issue but thought I'd mention. Somebody with more knowledge can clarify this...?

I think you’re very much right, but if they’ve already introduced a ton of air via bleeding procedures that might be the least of the problems right now.

 

[DrZed]

I think you’re very much right, but if they’ve already introduced a ton of air via bleeding procedures that might be the least of the problems right now.

If this is helpful I use a motive power bleeder and it has never failed me. Single person, super easy to use. One of the european adapters works on our car.

 

[17MagMetal]

If this is helpful I use a motive power bleeder and it has never failed me. Single person, super easy to use. One of the european adapters works on our car.

Those are definitely awesome, I think if the reservoir empties and the ABS control module takes air you’re forced to ID a shop/tech solution that can open the valves in the module to get air back out of them.

OP might be at the point of no return and have to either get the tech resources to do this full ABS bleed OR hit the dealer/indy shop for a bleed.

Someone on the forum might have some crazy Forscan hacks for this though, who knows!

 

[Spyshot]

thanks for the replies. sequence is farthest wheel to closest. Using manual pedal pumping method. The sound is coming from the brake system under the hood....master cylinder or that other box near it where the lines distribute from. (ABS PUMP maybe?) I'm sure we didn't suck air in from the bleeder while it was open, but it would come right back out anyway.

I just did a test drive and the brakes feel great. I'm out of fluid so when I get another bottle, I'll try bleeding some more.

Its just odd that my older son (who was probably pushing a lot harder) was able to induce the noise and my younger son did not.

 

[Spyshot]

edit: now that i’m thinking about it, that might also be normal hydraulic noises. If your reservoir never emptied itself you might just be worrying too much!

I'm starting to agree. I hope so anyway!

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