Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here XJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.

brake problem, help diagnose problem

Thread Tools
 
Search this Thread
 
Old Jan 1, 2014 | 07:03 PM
  #1  
1998xjspt's Avatar
Thread Starter
CF Veteran
 
Joined: Oct 2012
Posts: 1,277
Likes: 0
From: Orlando/Winter Garden
Year: 1998
Model: Cherokee
Engine: I6
Default brake problem, help diagnose problem

So my brakes are ****ty, in order for them to really engage i need to push almost all the way down to the floor. And there is a sweet spot that you hear a whistle while pushing brake pedal down. And if you keep the pedal in the sweet spot something whistles and does not stop til your out of the sweet spot. I thought about replacing brake booster but don't want to buy what i don't need. Anyone have any idea what's goin on? I have good amount of brake fluid, i bleed brakes multiple times. And replaced rotor, caliper and pads.

1998 xj sport
Reply
Old Jan 1, 2014 | 08:02 PM
  #2  
Firestorm500's Avatar
CF Veteran
 
Joined: Apr 2009
Posts: 4,734
Likes: 12
Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
Default

Replace brake booster.
Reply
Old Jan 2, 2014 | 08:00 PM
  #3  
1998xjspt's Avatar
Thread Starter
CF Veteran
 
Joined: Oct 2012
Posts: 1,277
Likes: 0
From: Orlando/Winter Garden
Year: 1998
Model: Cherokee
Engine: I6
Default

Will do. Now, iv heard all the hype about the booster upgrade to a zj one for all the older xjs. So will it do any difference to a 98 xj or is the 98 one good enough not to upgrade?
Reply
Old Jan 2, 2014 | 08:11 PM
  #4  
xjsnake's Avatar
CF Veteran
 
Joined: Aug 2010
Posts: 1,150
Likes: 1
From: Nashville, TN
Year: 1997, 1993
Model: Cherokee
Engine: 4.0L
Default

Originally Posted by 1998xjspt
Will do. Now, iv heard all the hype about the booster upgrade to a zj one for all the older xjs. So will it do any difference to a 98 xj or is the 98 one good enough not to upgrade?

You are good to go. Replace with OEM but make sure to check the vacuum line first before replacing the booster. Could just be a cheap rubber hose to replace instead of the booster.
Reply
Old Jan 2, 2014 | 08:41 PM
  #5  
highmileage's Avatar
CF Veteran
 
Joined: Oct 2011
Posts: 1,268
Likes: 1
From: Bakersfield CA
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Also verify it is not the vac fitting going into the booster.
Reply
Old Jan 2, 2014 | 11:47 PM
  #6  
Firestorm500's Avatar
CF Veteran
 
Joined: Apr 2009
Posts: 4,734
Likes: 12
Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
Default

The internal diaphragm is probably cracked.
Reply
Old Jan 4, 2014 | 10:54 PM
  #7  
1998xjspt's Avatar
Thread Starter
CF Veteran
 
Joined: Oct 2012
Posts: 1,277
Likes: 0
From: Orlando/Winter Garden
Year: 1998
Model: Cherokee
Engine: I6
Default

Okay so i replaced the brake booster and bled the brakes but when i go to step on brakes it still has to be pushed all the way down in order for braking to really start. I bled it til there was no bubbles. I noticed how the whistle was gone after new booster put in
Reply
Old Jan 4, 2014 | 10:57 PM
  #8  
Turbo X_J's Avatar
CF Veteran
15 Year Member
 
Joined: Sep 2009
Posts: 8,567
Likes: 20
From: ☼ Blackhole Sun
Year: My Jeep is a GMC
Default

Did you adjust the pushrod?
Reply
Old Jan 4, 2014 | 11:16 PM
  #9  
1998xjspt's Avatar
Thread Starter
CF Veteran
 
Joined: Oct 2012
Posts: 1,277
Likes: 0
From: Orlando/Winter Garden
Year: 1998
Model: Cherokee
Engine: I6
Default

No, left it how it came, didn't know it could/should be adjusted
Reply
Old Jan 4, 2014 | 11:21 PM
  #10  
Turbo X_J's Avatar
CF Veteran
15 Year Member
 
Joined: Sep 2009
Posts: 8,567
Likes: 20
From: ☼ Blackhole Sun
Year: My Jeep is a GMC
Default

Increase the length of the push-rod to decrease the amount of travel at the pedal.
Reply
Old Jan 4, 2014 | 11:32 PM
  #11  
1998xjspt's Avatar
Thread Starter
CF Veteran
 
Joined: Oct 2012
Posts: 1,277
Likes: 0
From: Orlando/Winter Garden
Year: 1998
Model: Cherokee
Engine: I6
Default

How?
Reply
Old Jan 4, 2014 | 11:45 PM
  #12  
Turbo X_J's Avatar
CF Veteran
15 Year Member
 
Joined: Sep 2009
Posts: 8,567
Likes: 20
From: ☼ Blackhole Sun
Year: My Jeep is a GMC
Default

http://www.jeepforum.com/forum/f11/b...ng-rod-291344/
Reply
Old Jan 5, 2014 | 03:20 AM
  #13  
freegdr's Avatar
CF Veteran
 
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
Default

Adjust up rear brakes b4 touching any thing else then bleed one more quick time....Don't really understand why brakes were bled but its been opened to air know..
Reply
Old Jan 5, 2014 | 08:52 AM
  #14  
1998xjspt's Avatar
Thread Starter
CF Veteran
 
Joined: Oct 2012
Posts: 1,277
Likes: 0
From: Orlando/Winter Garden
Year: 1998
Model: Cherokee
Engine: I6
Default

I discod the lines from the master cyl in order to take both master cyl and booster out, then swap cylinder to new booster. Which by removing lines, introduced air into the brake system, so i needed to bled the brakes...right? And okay will do. My helper said when i was bleeding brakes that it got really hard at one point but when i moved to the front it all of a sudden got soft
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
95cherokee89
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
59
Oct 16, 2015 03:17 AM
ammonllewis1
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
9
Aug 31, 2015 11:27 AM
madmanmarty
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
30
Aug 30, 2015 03:17 PM
britishcolumbia
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
7
Aug 28, 2015 04:08 PM
Cane
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
40
Aug 26, 2015 12:08 AM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 



All times are GMT -5. The time now is 06:29 PM.