question \ problem with vac brake booster on cj8 scrambler project - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 05-24-2009, 06:20 PM Thread Starter
Old Hand
Join Date: Nov 2007
Location: council bluffs iowa
Posts: 601
Thanks: 0
Thanked 0 Times in 0 Posts
Question question \ problem with vac brake booster on cj8 scrambler project

hi got a couple of quick questions on my power brake booster unit........Seems i have pleaty of vac coming from the intake but the brake booster unit is not keeping any vac after the motor is shut off............Also never have had very good power brakes and a buddy accross street just pulled the fitting off the booster and told me about it not keeping the vac and that it should,,,,,,, we went over to his chevy truck and he showed me that he had a bunch of vac on do i have a bad diaframe inside of the booster or something else...............The rubber seal does have cracks in it around the elbo fitting but i dont hear any vac leaks when the motor is running...............One more thing, on old 4 cyl motor that was in the scrambler before i swapped in the sb chevy the hose from the intake had about half way to the brake booster unit a small round canister that looks like a little barrel and i just left buddys truck just had the hose running all the way from the intake to the brake booster............. What is this thing and do it need it or could this be causing the problem...............I am planning on taking it out to see if that helps.......... I will get some photos on this what do you think..............should i be looking for a new brake booster unit thanks
myscrambler1 is offline  
Sponsored Links
post #2 of (permalink) Old 05-24-2009, 07:41 PM Thread Starter
Old Hand
Join Date: Nov 2007
Location: council bluffs iowa
Posts: 601
Thanks: 0
Thanked 0 Times in 0 Posts
Question cj brake booster

hi here are some photos of my unit on the cj and a couple of pic of some units i have found on ebay , the one of the vac booster only is a new jeep for a cj and the other is the kind of units i am finding sold as a complete unit..........i am thinking the new one should fit as a replacement for my unit as my master cyl is working ok.......
Attached Images
File Type: jpg Picture 379.jpg (103.7 KB, 1 views)
File Type: jpg Picture 378.jpg (102.4 KB, 0 views)
File Type: jpg 1f24_1.jpg (19.2 KB, 13 views)
File Type: jpg !BS5F91w!mk~$(KGrHgoH-CMEjlLl)s+(BKFelBOsjw~~_1.jpg (16.4 KB, 13 views)
myscrambler1 is offline  
post #3 of (permalink) Old 05-24-2009, 07:55 PM
Official Historian
WILL's Avatar
Join Date: Sep 1999
Location: Hot Springs, AR
Posts: 8,339
Thanks: 1
Thanked 5 Times in 5 Posts
If you have good boost on the brakes with the engine running, you may just need the little valve that is on the booster that the hose attaches to. No need to pull the booster to get to that. That valve is a one way valve that is supposed to retain the vacuum in the booster when the vacuum supply quits. If you hear a hissing sound from the inside of the jeep at the firewall then the booster is leaking. Those are the two most common ways it fails. Start with the valve though.

"As the circle of my knowledge grows, so grows the circumference of the unknown." - Isaak Newton

Last edited by WILL; 05-24-2009 at 08:02 PM.
WILL is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome