vibration in the brake pedal - 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 Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > vibration in the brake pedal

The Original 3/8" Ruffstuff Diff Cover!Building a Bumper?Introducing MONSTALINER™ UV Permanent DIY Roll On Bed Line

Reply
Unread 01-08-2003, 01:48 PM   #1
zyaround
Registered User
 
Join Date: Dec 2002
Posts: 9
vibration in the brake pedal

When I go past 15 mph, and then hit the brakes to stop the car does some sort of halfway ABS function. The brake pedal vibrates, the vehicle doesn't stop near as fast, and keeps going on, until it slows to 2 mph then all the vibration stops. This happens on dry pavement, literally every stop. When I hit ice and the wheels lock up, true ABS kicks in and the pedal really shakes, not the same feeling. If I drive at about 10 mph for 15 - 20 seconds the ABS light comes on, and the problem stops, but unfortunately so does my ABS protection. Any ideas?

zyaround is offline   Reply With Quote
Unread 01-08-2003, 06:10 PM   #2
Camster
Registered User
 
Join Date: Apr 2002
Location: Winston-Salem, NC
Posts: 308
i think you might have warped brake rotors, it's a really common problem in ZJ's (93-98). in my experience the whole car shudders when braking but it might trasfer just to the pedal if it's not too severe. just go to a mechanic to get it checked out. they'll know what you're talking about.
__________________
Cameron


[url=http://www.angelfire.com/nc2/davidpage/Camsjeep.html]My Jeep[/url]
Camster is offline   Reply With Quote
Unread 01-09-2003, 05:45 AM   #3
zyaround
Registered User
 
Join Date: Dec 2002
Posts: 9
Thanks for the idea, but I know that it's something to do with the ABS system. For one thing if it were rotors, hitting the brakes at highway speeds would give a shutter. But another thing is that if I drive the car at 10mph, while it's in the midst of the annoying vibratation with my foot off the pedal it's still doing it. If continued at the same speed for 20 sec it will stop and the ABS light comes on and the problem is fixed. It doesn't vibrate the pedal any more.

I appreciate your ideas though.
zyaround is offline   Reply With Quote
Unread 01-09-2003, 04:16 PM   #4
moabster
Registered User
2011 WK 
 
Join Date: Apr 2002
Location: Orem, Utah
Posts: 402
You did not mention what year your jeep is, but since this could be a saftey issue I would take it into a dealer and see if this is covered under warranty. Often saftey and emissions components are covered for a longer period of time than the normal 7/70 or 3/36 warranties. You can pull the fuse on the ABS system to see if this clears up the problem. That may help isolate the problem.

I would not completly rule out the warped rotor theory. Mine vibrated at slow speeds before they stared vibrating at high speeds. My ABS light never came on though.

Good Luck
__________________
2000 Jeep Grand Cherokee V8 Stock
93 YJ I6 hard top (really belongs to SPEED)
RE 4.5" Extreme Duty Lift, Advanced Adapters SYE, Tom Woods CV Drive Shaft, EA589 10" rims with 33" x 12.5" MT/Rs
Bullet Proof Front and Rear Bumpers and Tow bar
moabster is offline   Reply With Quote
Unread 01-10-2003, 08:03 AM   #5
zyaround
Registered User
 
Join Date: Dec 2002
Posts: 9
All good thoughts. My Jeep is a 98. Problem is that it has 150k miles. So I'm sure the fix is on me. That stinks too because it breaks left and right. Anywho, your right brakes are an important item to have on a car. So I have an appt scheduled for next week. The fuse on the system good idea, I tried that once before. I saw 2 fuses, one for the pump and one for (???). Neither looked like a master system fuse. I disconnected the battery negative cable and left it off for an hour, but it has an alt power source because not even my radio settings were off by the slightest (but yet it can't remember my seat position from one time to the next). I know it is the ABS system because once I get the ABS light to come on it stops fine, no problems. I plan to see what the mechanic says and then go buy the part at a junk yard. I'm sure it will be something in the ECU and cost a couple thousand, whereas I can get a used part for a couple hundred, and have about the same warranty.
zyaround is offline   Reply With Quote
Unread 01-13-2003, 07:51 PM   #6
Paul's GCL
Registered User
 
Join Date: Jun 2002
Location: Endwell, NY
Posts: 7
Z - I had a similar problem with my '96 GCL. Turned out to be the rear parking brake liner separated from the metal shoe and broke the driver side rear wheel speed sensor (there is one on each wheel that the ABS uses to detect lockup). The computer could not sense the rear wheel spinning so it was trying to engage the ABS each time I was on the brakes below 20 mph. Good luck!
__________________
Paul
'96 GC Laredo, 5.2L
Paul's GCL is offline   Reply With Quote
Unread 01-14-2003, 06:28 AM   #7
zyaround
Registered User
 
Join Date: Dec 2002
Posts: 9
Yeah, I took it to the dealer yesterday and they said it was the sensor on the back too. But the crazy thing is that I just replaced that sensor a couple weeks ago and this problem continued like before. They are replacing the new sensor, so if it was the sensor then I guess the other one was bad out of the box.

Good thoughts though!
zyaround is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





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.