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Mazda 2.2L \  Noise from carb when pushing brake...normal?

Noise from carb when pushing brake...normal?

Mazda 2.2L Mazda Engine Mazda Tech
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replies 10
following 4
 
rcogan   +1y
So I noticed last night while trying to bleed my brakes for 1,000th time, there is a odd noise coming out of carb when I press down brake pedal.
Never heard it before, but honestly can't say I was listening
Could this be an issue?
I'm still having issue building up a pedal
Builds up a descent bit when pumping, but if you stop for 10 seconds, it goes right back to floor
Goes to floor when truck is running

Let's see if this sound clip works
You can hear me pump pedal and the odd noise coming from carb

thread post photo
xxchromeghostxx   +1y
No, that is not normal. Thats a first for me. In my opinion, it sounds like your brake booster is bad and the lack of suction or ability to build pressure is just echoing pedal noise through the carb via the hose connected between the two. I may be completely in left field. But that's my guess. And are you sure its coming from the carb?
rcogan   +1y
Intake/carb for sure

I crawled all over under hood and thats where it is coming from

Booster is brand new. 3rd one
I was curious if the inline one way valve is backwards
Setup now to push air when pedal is pushed, no air when pedal is released
That's what arrow shows me to do, maybe it's marked backwards?
xxchromeghostxx   +1y
Maybe its a vacum leak on carb/intake. S itca weber or stock carb?_ the video was just black for me. Maybe if you get it running and use a can of ether or carb cleaner, squirt around your intake and carb where it mounts. But i am stumped. I have honestly never heard that on any make or model i worked on before.
rcogan   +1y
Weber
It runs, just wouldn't be able to stop it, that's only reason it's sitting still now
I'm gunna get some either and see if I can find anything
mazdatweaker_2   +1y


Have you adjusted the rears manually first? It sounds like that step needs to be done. Then you bleed the longest line first to remove the air.

From the drivers seat:
Right rear
Left rear
Right front
Left front

Maybe you have a blown wheel cylinder, but I would go back and maybe even pull the drums off and manually inspect the rears. You need to have the drums just lightly dragging the shoes when they are adjusted up properly. Otherwise you are pumping the brakes to take out the free play.

What you are hearing is not an issue, and I am pretty sure you have your valve installed properly.

Hope this helps.
rcogan   +1y
Rear brakes and all line are brand new
Hard lines, rubber lines, wheel cylinders, shoes, drums, adjusters, springs and retainers
Booster is new, master cylinder is new, vent hose is brand new.

Have adjusted them for enough out they drag pretty damn good

Im to the point I'm thinking either there's a vacuum leak I can't find, or air I somehow can't get out of lines for some reason.
Hoping atleast



Taking suggestions. Haha
mazdatweaker_2   +1y
I'd still pull off the drums and check for a blown wheel cylinder. Something is creating a lot of extra free space and that is the logical first place to check. After that I'd check every brake line connection for tightness / non-leaking, starting from the rear and working towards the front of the truck. Put someone in the driver's seat to pump up the brakes while you inspect for leaks . Pressurizing the lines will help find any problems. (Make sure the drums are back on)

I hope you let us know what you find.
xxchromeghostxx   +1y
These trucks only have one rear bleeder on the drivers side, just a fyi. They are connected together.
89bluedemon   +1y
That sound you hear is not normal when you hit the brake pedal. Should be a solid hiss from the booster only. You say that is your 3rd booster? What happened to the other 2? What I am wondering is where this inline valve is, I just went and looked mine over and didn't see one unless it's in that metal crossover tube.