Cj5 Brake Problems - 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 > Models > Jeep CJ Forum > Cj5 Brake Problems

Labor Day Sale!Clayton Off Road - last day of the Labor Day special!FS: Wrangler RGB Multicolor Fog Light LEDs: Awesome Effect

Reply
Unread 02-22-2014, 06:50 AM   #1
zbtc8
Registered User
1978 CJ5 
 
Join Date: Feb 2014
Location: Bristol, TN
Posts: 3
Cj5 Brake Problems

Hi everyone, I would love some help with my brakes. I have a '78 CJ5 and whenever I slowly depress the brake pedal it will sometimes travel almost completely to the floor until the brakes are activated. When it is depressed at a "normal" speed, however, the brakes feel and act normal. I've bled the brakes and don't think there is any air in them. Could this be a master cylinder problem? This issue can occur anytime I slowly depress them, whether it is during start up, after driving around for a while, or when it is hot or cold out. Also, I don't have a brake booster and I have discs up front with drums in the back.

zbtc8 is offline   Reply With Quote
Unread 02-22-2014, 08:13 AM   #2
John Strenk
Moderator
 
John Strenk's Avatar
1976 CJ5 
 
Join Date: Feb 2005
Location: Shalersville Ohio
Posts: 13,007
1. Is the fluid level OK?
2. Any sign of fluid leaks?
3, Have you checked the adjustment of the brakes in the rear?
John Strenk is offline   Reply With Quote
Unread 02-22-2014, 11:42 AM   #3
zbtc8
Registered User
1978 CJ5 
 
Join Date: Feb 2014
Location: Bristol, TN
Posts: 3
The fluid level is fine and surprisingly no leaks. The brakes in the back have been adjusted as well.
zbtc8 is offline   Reply With Quote
Unread 02-22-2014, 07:31 PM   #4
jeepdaddy2000
Web Wheeler
 
jeepdaddy2000's Avatar
1971 CJ5 
 
Join Date: Jan 2002
Location: Eagle Point Oregon
Posts: 6,169
Probably an internal master cylinder leak. The cups have probably shrunk. When you push slowly down, the fluid is passing between the bore and the lip of the cup. When you blast down on the pedal, the pressure rises quickly, forcing the cups up against the inside of the bore, sealing the cylinder.
I would think about replacing it.
jeepdaddy2000 is offline   Reply With Quote
Unread 02-22-2014, 07:47 PM   #5
jammer1
Member
 
Join Date: Jan 2009
Location: cleveland, ohio
Posts: 128
X2 Jeepdaddy2000. I had a jeep that did that and the rubber cups would let the fluid leak past. If I hit the brake hard, the pedal would be almost normal. If you hit the brake hard and stop, leave you're foot on the brake with pressure. If the rubber cups or the bore is scored, the petal will slowly go to the floor (as the fluid leaks past the cups).
jammer1 is offline   Reply With Quote
Unread 02-22-2014, 10:47 PM   #6
zbtc8
Registered User
1978 CJ5 
 
Join Date: Feb 2014
Location: Bristol, TN
Posts: 3
Looks like I'll be replacing the master cylinder and hoping that fixes it. Thanks and I'll keep you posted if it does!
zbtc8 is offline   Reply With Quote




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.