shansethp

95 runner 3.0 2wd. driving home(about 3miles) i started noticing my pedal took longer to push to the floor each time i stopped and it was really makeing a noise like air bowing by. Each stop it took longer to push it to the floor to get to the point where i could actually feel the brakes grab hold and start working. The last stop in my garage it was VERY difficult to push it to the floor and the air noise was at its worse. Talked to some peple and i got alot of check this but no real answers of what i should be looking for. Been reading posts on here and so far here is what i can say......No visable leaks, i cant hear any vac leaks under the hood. The vac hose running from the intake to brake cylinder isnt clogged. It still acts like a one way thing sucking from intake out of brake cylinder. One thing to note when i disconnected the vac line from the brake cylinder it let out a small rush of air(dont know what means?). I think from reading I should be focusing on the rear drum brakes? properly adjusted and or bleeding? Thoughts? Thanks in advance!

shansethp

Just noticed that now the entire time the brake pedal is depressed it makes a air noise like a ballon losing air. Its the worst at the initial pressing of the pedal as is the resistance but still even when brake pedal is all the way down it still has a small airy sound coming from the pedal area. Hopes this helps!

Sturmcrow

My guess is that your brake booster is leaking, allowing vacuum to slip past, and not building up power assist for your braking.

There is a simple check. Sit in the cab with the engine off and press the brakes a few times to get all of the vacuum out. Now, hold down the brake while starting the engine. If the booster is working properly, the pedal should sink down an inch or so. If it stays hard and up, then you need a new booster.

shansethp

Ok thanks i will go out and try that in a few minutes and get back with you!

shansethp

That didnt take long....lol. Yes it didnt move an inch. I pumped it and pushed it down and then started the motor and it didnt move at all, i did it twice just to be sure!! Brake booster huh.....any idea how much trouble it is to change one? Never done one. Again Thanks!

shansethp

also did a test i read about for the brake check valve (inline with intake and booster) where u disconnect at intake and suck on it........i could not suck or blow. i disconnected it for a second at booster and a bit of air came out then i hooked it back up and tried sucking again at hose that was connected at intake and could barely suck a little through it for a second then nothing, and i still cant suck anything through it at this point? Anybody know does this mean the vavle is bad?

Sturmcrow

The brake check valve would only matter while the engine is not running. It allows the booster to hold vacuum for a few emergency stops (that's why you needed to pump the brake a few times before the "starting the engine" test). You are correct that if it is somehow clogged, which is pretty unlikely, then your booster would be starved for vacuum and wouldn't work. From the booster side, you should only be able to blow through the check valve, not suck. The air (vacuum) flows from the booster to the intake.

Honestly, the fact that you are hearing an air leak, which is probably actually a vacuum leak, leads me to believe you have a hole in the brake booster diaphragm, and I think the only solution is replacement of the unit.

I have not changed a booster myself either. It could be as easy as unbolting the master cylinder and moving it out of the way, or it might be a lot more involved. Hopefully you will not need to remove any brake lines.

Sturmcrow

Here you go.

https://www.yotatech.com/forums/f116...stions-215539/

Don't say I never gave you nothin'

It looks to be a fairly straighforward replacement, you just need to be a contortionist to get to the clips and bolts under the dash.

shansethp

Thanks for the link, doesnt seem to be too involved! Also thanks for the help, I think also I am need of a new booster. After checking prices new vs used I am gonna try and find a local used one i think. One last question if you can help, total newb question too. How do I tell for sure if I have ABS? Im sure I dont.....but it appears the boosters are different if i have abs or not. I checked my dash with key on and no abs lights and ive never had the abs effect when hitting the brakes hard(that i remember). Always just assumed i didnt have them. Thanks again !!!!!!!!

Sturmcrow

The easiest way to tell is to look for the ABS box under the hood, or maybe an ABS fuse in the fuse block.

I would say you could find the ABS module under the hood by following the brake lines from the master cylinder. If they go straight to the brakes without passing through anything bigger than a T, then no ABS. If they go into a complicated looking boxy thing, then yes ABS.

shansethp

again thanks bro!!!