Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WJ > Wheels/Tires/Brakes

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 09-17-2013, 11:30 PM
StephenE's Avatar
Member
My Jeep: 2002 4.7L WJ
 
Join Date: Mar 2011
Location: Portland, OR
Posts: 116
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 1382
StephenE is on a distinguished road
2002 WJ Limited - Brake pedal travels to the floor

I had to brake hard to avoid someone who decided to turn at the last minute in front of me. Now when I press the brake pedal it travels almost to the floor. I have replaced all four calipers, all rubber lines with braided stainless and the master cylinder last year. I took the Jeep to have the brakes looked at today and they thought it was the master cylinder, so they replaced it. After bleeding the brakes, the pedal still travels to the floor when pressed. They tried another new master cylinder and it did the same (pedal travels to the floor after bleeding the brakes). The only items I have not replaced in the braking system are the booster and ABS module.

Has anyone else had this problem? Thoughts?
__________________

__________________
Stephen

2002 Jeep Grand Cherokee Limited 4.7l V8 Quadra-Drive
Wild Country XTX 245/65R17 tires on stock Avila rims
Quad-light mod, Transgo-HD2, SONNAX LB2
Bilstein 4600HD, JKS bar pin eliminators
Addco rear sway bar
R1Concepts drilled & slotted rotors, EBC Yellowstuff pads in front
Braided stainless steel brake lines
Infinity Reference 9633cf 6x9's, Kappa 63.9i 6.5", JBL 800GTi Sub in Bandpass box
Reply With Quote
  #2  
Old 09-18-2013, 02:12 AM
Frango100's Avatar
Premium Member

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,773
Thanks: 9
Thanked 67 Times in 65 Posts
Rep Power: 525696
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: 2002 WJ Limited - Brake pedal travels to the floor

The booster will not cause the pedal to go to the floor, only internal/external leak or air in the lines will cause that.
When the jeep is standing still and you press the pedal several times, does that make any difference? If it does, then for some reason the brake pads are pushed back too far after braking when driving, causing the need of more fluid to apply them again and consequently the brake pedal will go deeper then normal or even to the floor.
When you brake when driving, do you feel any vibration or pulsation in the pedal, which could indicate a warped disc?
Eventually the ABS controller could be faulty. It was probably activated during the heavy braking which you mentioned and maybe one of the valves is halfway stuck, dumping the pressure to the reservoir. You could look for a DRBIII scanner or any other scanner which could access the ABS controller, to activate the valves and maybe reset the stuck one or flush away any dirt which could hold it open.
__________________

__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #3  
Old 09-18-2013, 10:54 AM
StephenE's Avatar
Member
My Jeep: 2002 4.7L WJ
 
Join Date: Mar 2011
Location: Portland, OR
Posts: 116
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 1382
StephenE is on a distinguished road
Re: 2002 WJ Limited - Brake pedal travels to the floor

Quote:
Originally Posted by Frango100 View Post
The booster will not cause the pedal to go to the floor, only internal/external leak or air in the lines will cause that.
When the jeep is standing still and you press the pedal several times, does that make any difference? If it does, then for some reason the brake pads are pushed back too far after braking when driving, causing the need of more fluid to apply them again and consequently the brake pedal will go deeper then normal or even to the floor.
When you brake when driving, do you feel any vibration or pulsation in the pedal, which could indicate a warped disc?
Eventually the ABS controller could be faulty. It was probably activated during the heavy braking which you mentioned and maybe one of the valves is halfway stuck, dumping the pressure to the reservoir. You could look for a DRBIII scanner or any other scanner which could access the ABS controller, to activate the valves and maybe reset the stuck one or flush away any dirt which could hold it open.
Thanks Frank.
Pressing the pedal several times does nothing. There is no vibration or pulsation while braking. A DRB III scan tool is out of my budget. I read somewhere that I can remove the ABS relay and activate the pump by shorting two pins in the relay socket.

Anyone ever buy a used ABS pump from a junkyard? Would an ABS pump from the junkyard be reliable?
__________________
Stephen

2002 Jeep Grand Cherokee Limited 4.7l V8 Quadra-Drive
Wild Country XTX 245/65R17 tires on stock Avila rims
Quad-light mod, Transgo-HD2, SONNAX LB2
Bilstein 4600HD, JKS bar pin eliminators
Addco rear sway bar
R1Concepts drilled & slotted rotors, EBC Yellowstuff pads in front
Braided stainless steel brake lines
Infinity Reference 9633cf 6x9's, Kappa 63.9i 6.5", JBL 800GTi Sub in Bandpass box
Reply With Quote
  #4  
Old 09-18-2013, 11:32 AM
Frango100's Avatar
Premium Member

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,773
Thanks: 9
Thanked 67 Times in 65 Posts
Rep Power: 525696
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: 2002 WJ Limited - Brake pedal travels to the floor

I did not mean to say to buy a DRBIII, just to look for a garage who has one, or a comparable scanner, so that the ABS can be tested.
If you can find a used unit from a junkyard I would say why not. If it looks clean and undamaged from the outside and is packed in plastic to prevent foreign material to get in(when it is already removed from the vehicle), it should be ok.
__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #5  
Old 09-18-2013, 06:53 PM
StephenE's Avatar
Member
My Jeep: 2002 4.7L WJ
 
Join Date: Mar 2011
Location: Portland, OR
Posts: 116
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 1382
StephenE is on a distinguished road
Re: 2002 WJ Limited - Brake pedal travels to the floor

Frank,
I purchased a used ABS module and installed it. After bleeding the brakes at the ABS module and at each wheel cylinder (in proper order) I have brakes that feel and behave like normal. I am only out $79.97 for the used ABS module and brake fluid plus a few hours of my time.

I will update this thread if there are any new developments.

Thanks for your help Frank.
__________________
Stephen

2002 Jeep Grand Cherokee Limited 4.7l V8 Quadra-Drive
Wild Country XTX 245/65R17 tires on stock Avila rims
Quad-light mod, Transgo-HD2, SONNAX LB2
Bilstein 4600HD, JKS bar pin eliminators
Addco rear sway bar
R1Concepts drilled & slotted rotors, EBC Yellowstuff pads in front
Braided stainless steel brake lines
Infinity Reference 9633cf 6x9's, Kappa 63.9i 6.5", JBL 800GTi Sub in Bandpass box
Reply With Quote
  #6  
Old 09-18-2013, 10:53 PM
Frango100's Avatar
Premium Member

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,773
Thanks: 9
Thanked 67 Times in 65 Posts
Rep Power: 525696
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: 2002 WJ Limited - Brake pedal travels to the floor

Good to hear that the problem is solved.
Did you change the complete assy, which consist out of the HCU (hydraulic control unit= valve unit) and the CAB (controller antilock brake= electronic controller)? The manual calls for reprogramming the CAB when it is changed, but i have no idea what the programming does. If you could find a place with a DRBIII scanner, then you could test the ABS and see if it performs ok.
__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #7  
Old 09-19-2013, 01:09 AM
StephenE's Avatar
Member
My Jeep: 2002 4.7L WJ
 
Join Date: Mar 2011
Location: Portland, OR
Posts: 116
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 1382
StephenE is on a distinguished road
Re: 2002 WJ Limited - Brake pedal travels to the floor

Frank,
I changed out both the CAB and HCU. A few preliminary tests in gravel indicate that ABS is working. I currently have less than 1 inch pedal travel until I feel the brakes grab. If I can find someone with a DRB III scan tool I will ask them to run the ABS test.
__________________

__________________
Stephen

2002 Jeep Grand Cherokee Limited 4.7l V8 Quadra-Drive
Wild Country XTX 245/65R17 tires on stock Avila rims
Quad-light mod, Transgo-HD2, SONNAX LB2
Bilstein 4600HD, JKS bar pin eliminators
Addco rear sway bar
R1Concepts drilled & slotted rotors, EBC Yellowstuff pads in front
Braided stainless steel brake lines
Infinity Reference 9633cf 6x9's, Kappa 63.9i 6.5", JBL 800GTi Sub in Bandpass box
Reply With Quote
Reply

Thread Tools
Display Modes

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 Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Brake pedal question jp467 Trouble Shooting/Problems/Service 10 09-23-2012 05:09 PM
Squeaking brake pedal MoxX Trouble Shooting/Problems/Service 8 11-08-2011 07:50 AM
Low Brake Pedal leadgtrplayr Grand Cherokee - ZJ 13 04-16-2011 06:40 PM
new brake/gas pedal Mattman611 Grand Cherokee - WK 4 01-27-2011 02:23 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 02:03 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community