Brake booster whistle

hey everyone I just replaced my brake booster, now my brake pedal is very stiff and there's a whistle coming from the brake booster. I checked all the hoses and sprayed soapy water in them and couldn't find a leak. Has anyone had this happen before or have any advice? The video won't upload but here's a few pics of the new one installed

 

if there is no vacuum assist the booster in not functioning... the whistle is the vacuum leak from the diaphram that is tore. A good booster should hold enough vacuum for maybe 2 full brake applications before it gets firm. Squeeze the vacuum line that goes to the intake and see if the idle speed improves and drops, if so, the booster is not holding.

 

Ok I'll check that tomorrow. Just to be sure, the vacuum line is the line in the second pic correct? I'm Pretty new to doing it yourself and this was my first project so I'm still trying to learn everything

 

Yes. This should help you visualize what is happening or should be happening inside when it's working.

 

Thanks! That video helped a lot

 

So I squeezed that hose today. The engine didn't rev up or down but as soon as I squeezed the hose the whistle went away. Any ideas?

 

the metal bit that the hose connects to is a check valve.

 

It looks likes it seated good and I've sprayed soot water all around it and it doesn't seem to be leaking. As much as I would hate to take that thing back out again is it possible I just got a bad brake booster?

 

Soapy water*

 

Actually spraying soapy water will not help with detecting vacuum leak. Bubbles would form inside the leaking part and you will not be able to see it. So if you hit a leaking place with soapy water the only thing you did was adding some water to the guts of the booster.

If your booster is whistling and not working it has a leak. Not necessary big leak causing air bypass increasing the rpm but it is enough to stop booster from keeping a vacuum and playing a flute. If you can't see from the outside any visible hole my guess is to take it out and then check for leaks or improper operation. I don;t know if applying a slight pressure instead of vacuum to the booster would cause some damages. If not you may try apply a slight air pressure to the buster and then check with soapy water. But again I DO NOT KNOW IF PRESSURE WILL NOT DAMAGE THE BOOSTER.

 

If you pinch that hose and the noise stops AND you have confirmed that the plastic check valve is sealed and not itself leaking (including the hose connection to it), better break out those tools because the booster is bad. Sucks. I've replaced probably 25 boosters and thankfully never had a bad new part. How crappy was the process? Some are easy and some...

 

Thanks everyone for the help. Ill return it and get a new one. The process isn't to bad except for the top bolt behind the brake pedal. It's a pain to get off and then pulling the booster itself out took a while, just not enough room

 

I have the same issue - hissing after shutting down engine and constant while driving.
I have replaced the hose as it was cracked at one end.
Also replaced the union that connects the manifold and all the hose clamps.
Next would be to replace the check valve.

If you have a part number for the brake booster, please let me know...

 

when you have the booster out examine the master cylinder to booster seal. It is round and fits down inside the bore that the master cylinder slides into. There is a possibility of tearing this seal also when you reinstall the master cylinder especially when you leave the brake lines attached to the master cylinder and wrestle it out of the way.

 

I've noticed that's come up a couple times in the last few months.

 

Well I feel stupid now, it's that inside seal. The new one didn't come with any seals. I had to call a Toyota dealership to get the paper seal between the master cylinder and brake booster and he told me I didn't need one for the back of the brake booster so once I got everything apart I figured the inside was the same.

Yeti -I'll check the box and receipt when I get home tomorrow. The part number is on the back of the booster but I got on autozone and put in my vehicle info and it will come up

 

I ment to add pics of the old and new one with the last post but her they are

 

So I finally got the new brake booster, put everything back together and everything works great!

 

Anyone have a vid on how to replace the gasket in between the cylinder and the booster thank you so much

 

was driving today pulling up to gas station slow down and brakes sort of went out now brake pedal is pretty stiff and no brakes I sprayed some soapy water between the cylinder and the booster and am hearing some hissing I believe it’s the gasket does that sound correct would I lose brake assist and basically braking if there’s a leak in between the booster and the gasket could that be why I barely have any braking again thank you