Brake Problems - JeepForum.com
 
LinkBack Thread Tools
post #1 of 10 Old 12-07-2002, 04:57 PM Thread Starter
dallen
Registered User
 
Join Date: Oct 2002
Location: Auburn CA
Posts: 15
Brake Problems

Hi all. I have a 1986 CJ7. When I bought it, it had rear disc brakes. I didnít install them or have them installed so I know very little about them. My problem is the brake pedal goes all the way to the floor when I first start out. After I pump them once or twice everything is OK except when I am wheeling. If I am going up or down a Simi steep hill the brakes need to be pumped. This does not happen every time though. I have bleed the breaks several times with no change. I can not see any leaks and I donít use or loose any fluid. I could really use some help with this one. Thanks.

dallen is offline  
Sponsored Links
Advertisement
 
post #2 of 10 Old 12-08-2002, 06:52 AM
jadams68
Registered User
 
jadams68's Avatar
1984 CJ7 
 
Join Date: Aug 2002
Location: Downingtown, PA
Posts: 2,898
It sounds to me that if someone did a disc brake conversion on your CJ, that they may not have used a proper disc brake master cylinder.

-----------------------
I used to own two CJ's...Perhaps a 3rd is in the future?
jadams68 is offline  
post #3 of 10 Old 12-08-2002, 08:22 AM
CJeep
Alpha dog
 
CJeep's Avatar
1982 CJ8 
 
Join Date: Apr 2001
Location: Near Fairfield, CT
Posts: 1,216
Cool

Assuming the the PO did not chage the master cyclinder or proportioning valve, you may have some headaches ahead of you.

While the fronts do most of the stopping, the rear (stock) drums account for most of the pedal movement. It take a lot less fluid to move disc calipers compared to drum brake shoes.

My guess would be that a new proportioning valve would fix your problem, but I have no idea what the right proportions need to be. I'd check with an expert, hot rodders do a lot of drum-disc conversions, but it may require a good deal of trial and error.

'82 Scrambler - NV4500/4.5" lift/33" Toyo MTs/4.0/twin stick, and my windshield washers work! Full 1/2 cab Cage

2004 Grand Limited 4.7 HO - OH Boy!

2010 Grand Laredo 5.7 Hemi - SICK - work vehicle -gone - replaced by an 08 Tahoe - nice ride.

"Both my Doberman and my Jeep can accurately be described as 'black and rust.'"

"I got a fever . . . and the only prescription is more cowbell"
CJeep is offline  
post #4 of 10 Old 12-08-2002, 09:24 AM
rustyCJ
Registered User
 
Join Date: Sep 2002
Location: IL
Posts: 938
contact SSBC or SBSC or something like that, they are the most common manufacturers of aftermarket disc conversions for jeeps. i contacted them about how to convert my rear to disc, they will beable to answer all of your questions.

"character is doing the right thing even if nobody is looking"
rustyCJ is offline  
post #5 of 10 Old 12-08-2002, 10:27 AM Thread Starter
dallen
Registered User
 
Join Date: Oct 2002
Location: Auburn CA
Posts: 15
Thanks for all your help. I think I need to look into a bigger master cylinder.
dallen is offline  
post #6 of 10 Old 12-08-2002, 01:23 PM
crotz83
Registered User
 
crotz83's Avatar
 
Join Date: Nov 2002
Location: Dallas, TX
Posts: 43
i have the same exact problem with my scrambler, i doesn't seem that the front discs' pads wear hardly at all...i need some help with this subject as well, for the record i don't dig headaches i would just like a fix if anyone knows...i don't think the master cylinder has been changed on mine....is there anything dealin with vaccuum from the engine that affects brake pressure?? just a question

83 Scrambler, 33" mud terrains, NV4500, Centerforce Clutch, Dana 300, 350 ci, edelbrock 650 carb, 4" BDS springs, ss braid brake lines, currie greasable shackles, OBA-YORK-2.5gal tank, Hood lift

92 YJ, 35" Procomp Xtremes, SOA on stock springs, Heavy duty shackles, TJ long side shaft, JB Conversions SYE, JB4x4.com steering, 4.0l, ss braid brake lines
crotz83 is offline  
post #7 of 10 Old 12-08-2002, 02:06 PM
jadams68
Registered User
 
jadams68's Avatar
1984 CJ7 
 
Join Date: Aug 2002
Location: Downingtown, PA
Posts: 2,898
Crotz,

Yes, if you have power brakes. The Vacuum booster draws air from a tube coming out of the engine intake manifold. Vacuum is created while the engine is running (no kidding) and when you press the pedal down, the input rod is pushed forward in the booster which blocks a port in the diaphragm and opens another port causing the vacuum to shove the push rod into the master cylinder.

-----------------------
I used to own two CJ's...Perhaps a 3rd is in the future?
jadams68 is offline  
post #8 of 10 Old 12-08-2002, 04:18 PM
crotz83
Registered User
 
crotz83's Avatar
 
Join Date: Nov 2002
Location: Dallas, TX
Posts: 43
okay, well i have a 350 chevy ....maybe i should check for this vaccuum connection then....any other ideas??

83 Scrambler, 33" mud terrains, NV4500, Centerforce Clutch, Dana 300, 350 ci, edelbrock 650 carb, 4" BDS springs, ss braid brake lines, currie greasable shackles, OBA-YORK-2.5gal tank, Hood lift

92 YJ, 35" Procomp Xtremes, SOA on stock springs, Heavy duty shackles, TJ long side shaft, JB Conversions SYE, JB4x4.com steering, 4.0l, ss braid brake lines
crotz83 is offline  
post #9 of 10 Old 12-08-2002, 09:29 PM
RockJeep
Motobilt.com
 
RockJeep's Avatar
1998 TJ Wrangler 
 
Join Date: Nov 2000
Location: Dothan
Posts: 272
go to the parts store and tell them you want a Master cylinder for a 68 corvette w/4 wheel discs. should bolt right up, about 15 bucks plus a core charge. it should have an almost equal resevoirs, also its got a longer stroke bigger bore, 1", and should solve your problems. if your rear brakes start to drag on the street at all you can get a willwood adjustable proportioning valve for the rear and tune the brake pressure.
later
bob
p.s. for some serious stopping power swap in a hydraboost setup from a diesel.

1998 Jeep TJ on 37's, locked, long armed etc
Sales Manager at http://www.motobilt.com
RockJeep is offline  
post #10 of 10 Old 12-09-2002, 09:39 PM
Jeep Daddy
Registered User
 
Jeep Daddy's Avatar
2004 TJ Wrangler 
 
Join Date: Jan 2002
Location: Orange County
Posts: 1,278
I don't think you need a larger master cylinder - just get a new one to start with. Those are symptoms of a bad master . . . plain and simple. Lets assume that the brakes were converted corectly by the PO and that they worked properly after the conversion. Unless you know that the PO got rid of the Jeep because he couldn't figure out his brake problem.

So, I'd just get a new MC, be sure to compare the old one to the new one and swap it out. Should only take about 15 minutes to swap out, then bleed. Make sure you bleed all the wheels starting with the farthest wheel.

2004 Rubicon, 6" lift, 35s, winch, hard top, full doors, bumpers, tire carrier and rock sliders.
Jeep Daddy is offline  
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.



Email Address:
OR

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.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Power brake problems Jeepguy91 Jeep CJ Forum 10 04-17-2009 03:51 AM
Brake Problems gwalls Jeep CJ Forum 24 12-22-2008 08:39 AM
Rear Brake Problems?? bstylee33 Jeep CJ Forum 5 06-01-2005 08:56 PM
Brake Problems, Need Help DEERSLAYER1407 Jeep CJ Forum 1 05-10-2005 08:22 PM
Brake Problems HELP!!! scottahicks Jeep CJ Forum 4 03-02-2003 09:08 PM

Posting Rules  
You may post new threads
You may 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 Off
Pingbacks are On
Refbacks are On

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