vibration under light braking

[Dman1100]

my 240 is making a nasty sound/vibration under light braking. it stops when the pedal is depressed harder. i'm not real sure if it's the vacuum or if the problem lies in the brake booster. anyone experience this or have any ideas? it also seems to affect the idle slightly. i have removed the aiv and plugged the vacuum lines going to it.

 

[phunky.buddha]

Warped rotors?

 

[Kcihcaton]

That was my first thought, but warped rotors would cause vibration throughout braking, not just light braking... at least if they're warped badly.

 

[civicious]

Never too early to get your rotors turned.

 

[Slammed90Lude]

 

[Dman1100]

it's not the rotors because it also makes this vibration while at a stop. i'm almost certain it's the diaphram pulsating back and forth. but i don't know whether the problem lies in the booster or the vacuum system.

 

[civicious]

hehe...diaphram...hehe...

 

[Seany-izzle]

hahaahah thats exactly what i said...

 

[K2e2vin]

maybe a bad check valve or the diaphram is leaking. from the sound of it, it sounds like it might not be sealing/closing right. the vibration you feel is probally from the brake booster going on and off(air going in and out, when air is supposed to be pulled out at all times)

 

[Dman1100]

Originally posted by CRVTEC+Dec 2 2004, 06:21 PM-->

hehe...diaphram...hehe...

[post=425241]Quoted post[/post]​

Originally posted by Seany-izzle@Dec 2 2004, 07:30 PM
hahaahah thats exactly what i said...

[post=425287]Quoted post[/post]​

I knew you would

K2e2vin@Dec 2 2004, 08:30 PM
maybe a bad check valve or the diaphram is leaking. from the sound of it, it sounds like it might not be sealing/closing right. the vibration you feel is probally from the brake booster going on and off(air going in and out, when air is supposed to be pulled out at all times)

[post=425348]Quoted post[/post]​

Thats what i'm thinking where could the check valve be? that would be the easiest fix. i hope it's not the booster, that would just be a pain in the ass

 

[K2e2vin]

its usually white and around the master cylinder; follow the vacuum hose to the booster and it should be inline with the hose(looks like a male coupler). heres where it is on a crx:

 

[Dman1100]

thanks i'll check it this weekend

 

[TurboMirage]

my 240sx didnt have one.

 

[K2e2vin]

it maybe has a built in one? i looked around and didnt find anything one the internet about a 240sx having a check valve. unless it has a totally different brake booster system, there has to be something that keeps vacuum in the brake booster.

 

[hcivic.com]

the rotors need turning they will vibrate under light braking but with the extra force from hard braking it will go away

 

[K2e2vin]

Originally posted by hcivic.com@Dec 5 2004, 04:34 PM
the rotors need turning they will vibrate under light braking but with the extra force from hard braking it will go away

[post=426597]Quoted post[/post]​

when my rotors were warped it actually got worse the harder you step on the brakes.

 

[hcivic.com]

not warped just cut up if there warped turning won't help

 

[Dman1100]

the check valve is alright so it's probably in the booster. does anyone know if the brakes need bleeding when you work with the booster?

 

[K2e2vin]

if you remove the MC or anywhere where brake fluid comes out(like some lines), yes.

 

[Dman1100]

thats what i thought but wasn't sure if you could keep the system closed and still get to the booster. looks like i've got something to do for a while. i need to do it even worse now that the brake light comes on once in a while