Brakes boging down idle??? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > General Technical Discussions > Engines & Drivetrain > Brakes boging down idle???

Currie Antirock, Currectlync & Lift Kits on Sale!Oconee Off-Road Free Shipping Lifts Tires Bumpers Tops andIntroducing MONSTALINER™ UV Permanent DIY Roll On Bed Line

Reply
Unread 12-30-2012, 09:06 AM   #1
scottcj71979
Registered User
1979 CJ7 
 
Join Date: Nov 2012
Location: jacksonville, fl
Posts: 29
Brakes boging down idle???

When I press the brakes and apply pressure it bigs down idle and when it's cold can kill the engine. The pressure I have to use to get it to stop seems much stronger lately as well.

Is it something to do with my brake booster? Can this be adjusted in anyway? Anything to look for?

Thanks for the help!

scottcj71979 is offline   Reply With Quote Quick reply to this message
Unread 12-30-2012, 10:05 AM   #2
turbolx
Registered User
 
Join Date: Aug 2008
Location: Prague, Oklahoma
Posts: 1
Sounds like you have a leak in the booster diaphragm. It runs off of vacuum from the engine and if there is a leak in the diaphragm, it will cause a vacuum leak in the engine and affect the idle speed.
turbolx is offline   Reply With Quote Quick reply to this message
Unread 12-30-2012, 10:12 AM   #3
90DesertTanYJ
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2012
Location: Jacksonville, FL
Posts: 750
Quote:
Originally Posted by turbolx View Post
Sounds like you have a leak in the booster diaphragm. It runs off of vacuum from the engine and if there is a leak in the diaphragm, it will cause a vacuum leak in the engine and affect the idle speed.
I agree. The added effort on the brake pedal is your next clue. Just like pushing the pedal after the Jeep is turned off. Eventually you have to stand on them for them to work.
90DesertTanYJ is offline   Reply With Quote Quick reply to this message
Unread 12-30-2012, 06:09 PM   #4
scottcj71979
Registered User
1979 CJ7 
 
Join Date: Nov 2012
Location: jacksonville, fl
Posts: 29
Yep did some trouble shooting and it's Definatly the brake booster. Guess it has a leak internally so I'm going to replace the whole unit and master cylinder from a 1979 wagoneer. For some reason at the parts store they didn't have one under any cj models but did for the wagoneer. It looked the same as the one I have on there. Hopefully it works.?

I was 4x4 in low all night long then it started to leak. 35" tires plus upgraded axels doesn't help I'm sure, but it looks original so maybe it was just its time to retire?
scottcj71979 is offline   Reply With Quote Quick reply to this message
Unread 01-01-2013, 07:35 AM   #5
scottcj71979
Registered User
1979 CJ7 
 
Join Date: Nov 2012
Location: jacksonville, fl
Posts: 29
Bump
scottcj71979 is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.