Become a Fan!
Login
Username:

Password:

Remember Me

Lost Password?

Register now!
Main Menu
Who's Online
40 user(s) are online (32 user(s) are browsing Forums)

more...
Guru Dictionary
 Register To Post

Lichen Cold weather and brake booster
Guru
Scottsdale, Arizona
166 Posts
Member since:
2007/11/27 19:00



Offline
A couple of weeks ago, I got the dreaded hissing sound from the booster. I replaced the check valve and thought that fixed it. We had a couple of weeks of cold weather (for Phoenix) 30 - 40*. Anyway, I've discovered that when it is cold, the booster hisses. In the afternoon when it's warm (65-70*), no hissing and the brakes work great. What would you check?
Posted on: 2008/1/3 11:14
Transfer the post to other applications Transfer

CasetheCorvetteman RE:Cold weather and brake booster
Elite Guru
QLD, Australia
2071 Posts
Member since:
2006/7/17 20:00



Offline
Here is some info for ya mate. First thing id ask is does it hiss with foot on pedal? Off pedal? Or both?

When your foot is off the pedal, both the front and rear of the booster is subject to vacuum, by pushing on the pedal, the reaction disc will seal off the front section from the rear, and the rear valve will open, which allows the rear to return to atmospheric pressure, which in turn will result in the vacuum piston being drawn toward the front of the booster.

In the case of a damaged shell (front or rear), the vacuum leak will be always present, foot on the pedal or not. You wont hear any hissing inside the car if this is the case.

If indeed the main diaphramn fails, you can bet the rear main seal wont be far behind it.

If the rear main seal has failed, you may have a hissing sound when your foot is OFF the pedal, which should go away when the brake is pressed if the main diaphramn is ok, and the booster may even still appear to work normally.

The check valve is only present to stop vacuum from leaving the booster through the front when the vacuum level in the manifold drops. Air can be drawn out of the booster through this valve, but not back in. That is all this piece does.
Posted on: 2008/1/4 3:20
Transfer the post to other applications Transfer

Lichen RE:Cold weather and brake booster
Guru
Scottsdale, Arizona
166 Posts
Member since:
2007/11/27 19:00



Offline
Thanks, Case. It only hisses when the pedal is depressed. Once the outside temperature gets around 60*, there is no hissing at all.
Posted on: 2008/1/4 9:57
Transfer the post to other applications Transfer

CentralCoaster RE:Cold weather and brake booster
Senior Guru
San Diego, CA
9160 Posts
Member since:
2007/10/27 20:00



Offline
It's normal to get a slight whoosing noise when pressing the pedal down with the car on, this is the diaphram refilling itself from air inside the car. There's some little holes up by the brake pushrod just for this. But it shouldn't be very noticable.
Posted on: 2008/1/4 11:00
Transfer the post to other applications Transfer

CasetheCorvetteman RE:Cold weather and brake booster
Elite Guru
QLD, Australia
2071 Posts
Member since:
2006/7/17 20:00



Offline
No if youre noticing continual hissing with the foot on the pedal but it goes away when it warms up, it could even be the reaction disc. A little bit is normal, but not much.
Posted on: 2008/1/5 1:39
Transfer the post to other applications Transfer

You can view topic.
You cannot start a new topic.
You cannot reply to posts.
You cannot edit your posts.
You cannot delete your posts.
You cannot add new polls.
You cannot vote in polls.
You cannot attach files to posts.
You cannot post without approval.

[Advanced Search]


CorvetteGuruForum.com is independently owned and operated. This site is not associated with or financially supported by General Motors.

Copyright 2008-2012 CorvetteGuruForum.com

This site is available through the following URL redirects: C4Guru.com, CorvetteGuru.com, Corvette-Guru.com and CorvetteGuruForum.com. Email is sent from and received by CorvetteGuruForum.com ONLY!

CorvetteGuruForum.com is a Guru Garage Site (Coming Soon!)

If you have any questions about our site, please contact us at admin@corvetteguruforum.com.

Powered by XOOPS 2.53 Copyright 2001-2012 The XOOPS Project.

Hosted by BeanTown Host.