OEM Parking Brake Lever Study - 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 Wrangler Forums > JK Wrangler Technical Forum > OEM Parking Brake Lever Study

BLACK FRIDAY SPECIALS!! You asked, we deliver!FS: Wrangler RGB Multicolor Fog Light LEDs: Awesome EffectRockridge 4WD IS Taking Zone Offroad Suspension Lift Kits

Reply
Unread 07-01-2010, 07:04 PM   #1
ronjenx
Web Wheeler
 
ronjenx's Avatar
2008 JK Wrangler 
 
Join Date: Jan 2009
Location: Maine
Posts: 3,941
OEM Parking Brake Lever Study

I have been wondering how the parking brake lever works.
People have had it fail, and it was not clear to me what failed.
This is how it works:

1. Here is an overview of the passenger side of the parking brake lever assembly.
The pin which loops over the black lever is installed to keep the tension spring from unwinding. It is removed after the cables are connected.





2. Here is an overview of the driver's side of the parking brake lever assembly.





3. A more detailed view of the various parts.
The tension spring is attached to the cable drum.
It keeps about 20 pounds pull on the cable when the parking brake is released. This removes the slack from the system.
The cable drum is made from two pieces, with one piece extending under the clutch spring.
The clutch spring is wound around the drum tightly enough to be a friction fit on the drum.
One end of the clutch spring extends from the bottom of the spring, and is anchored to the parking brake lever.
Lifting the lever causes the clutch spring to wind even more tightly around the drum, so the drum rotates with the lever, which pulls on the brake cable.






4. As the lever is pulled up, the clutch spring, being anchored to the lever, rotates, tightening itself on the drum.
This drags the drum around with it, pulling the cable.
The clutch spring tail moves away from the stop, which is actually the thing that allows the clutch spring to wind itself tighter on the drum.






5. Here the lever has been raised as if to apply the parking brake.
The spring clutch tail has also rotated away from the stop.
If you were to pull on the tail, toward the camera, it would unwind the clutch spring, making its diameter bigger, thereby releasing the cable drum. The lever position would not change, though. It would move freely as long as you followed the rotation with the spring tail.
When the lever is returned to the down position, the clutch spring tail also rotates toward the stop. It hits the stop just before the lever bottoms out. This releases the clutch spring, and the tension spring is free to rotate the cable drum, maintaining 20 pounds tension on the cable.






6. Here you see what breaks when you go to apply the parking brake, and hear a loud SNAP!
The lever will then be free to move, and no torque will be applied to the cable drum.


An ineffective parking brake could be caused by any one of several things:
Worn shoes
Shoes out of adjustment
Broken cable(s)
Broken clutch spring arm
Slipping clutch spring
Broken tension spring

ronjenx is online now   Reply With Quote Quick reply to this message
Unread 07-01-2010, 09:09 PM   #2
JLC08JK
What was I thinking?
 
JLC08JK's Avatar
2008 JK Wrangler 
 
Join Date: Sep 2009
Location: Los Angeles, California
Posts: 5,803
Whatever happened to just a lever with a cable attached?
Thanks for the insight
This will more than likely be helpful in the future
__________________
Jim
Jim's Jeep; THE OBSESSION LIVES ON!
Jim's JK D44 Rear Axle Build

99% of Your JK Questions will be Answered Here
JK F.A.Q./WILL IT RUB and Popular Threads

Protect Our Rights to Freedom and the Environment
Visit the EnviroBeat
JLC08JK is offline   Reply With Quote Quick reply to this message
Unread 07-01-2010, 09:47 PM   #3
plac
Registered User
2012 JK Wrangler 
 
Join Date: May 2006
Location: CA
Posts: 1,425
you dog..
__________________
2013 VW GTI
plac is offline   Reply With Quote Quick reply to this message
Unread 07-01-2010, 10:37 PM   #4
JeepScout3
Registered User
2010 JK Wrangler 
 
Join Date: May 2010
Location: San Antonio, TX
Posts: 311
Very informative. Not sure if I will need to know this, but having this knowledge, like anything else, could come in handy one day. Thanks for a solid overview.
__________________
2010 Charcoal Grey JK 2Dr Sport, Hardtop, 6 Speed Manual, 3.73 gears

"My 3rd Jeep, previously owned a YJ and TJ"
JeepScout3 is offline   Reply With Quote Quick reply to this message
Unread 08-08-2010, 04:29 PM   #5
djkbooth
Registered User
2010 JK Wrangler 
 
Join Date: Dec 2009
Location: virginia
Posts: 254
Bump!!

Good info for others!!!
djkbooth is offline   Reply With Quote Quick reply to this message
Unread 09-15-2010, 11:10 AM   #6
duramax58
Registered User
 
Join Date: Sep 2010
Location: somerset
Posts: 1
e-brake assembly

thanks great photos BIG help jim
duramax58 is offline   Reply With Quote Quick reply to this message
Unread 09-15-2010, 12:04 PM   #7
tennistom1
Registered User
2009 JK Wrangler 
 
Join Date: Aug 2006
Location: Left Coast
Posts: 917
Great write-up and pics, Ronjenx. This Rube Goldbergian contraption, was no doubt a by-product, of the short-term marriage between Daimler & Chrysler. As with most Mercedes products, over-engineered in my opinion. I'm sure next time I'm on the Autobahn, the tow-truck driver, will have the spare part on top of his dash and it will be a snap for him to r/r. Probably does not lend itself well to trail fixes, glad I just bought a set of folding wheel-chocks. I will pull more gingerly from now on.

Thanks!
__________________
2009 JK Rubicon 4-Door
2006 TJ Rubicon Unlimited
tennistom1 is offline   Reply With Quote Quick reply to this message
Unread 09-15-2010, 12:46 PM   #8
ronjenx
Web Wheeler
 
ronjenx's Avatar
2008 JK Wrangler 
 
Join Date: Jan 2009
Location: Maine
Posts: 3,941
Quote:
Originally Posted by tennistom1 View Post
Great write-up and pics, Ronjenx. This Rube Goldbergian contraption, was no doubt a by-product, of the short-term marriage between Daimler & Chrysler. As with most Mercedes products, over-engineered in my opinion. I'm sure next time I'm on the Autobahn, the tow-truck driver, will have the spare part on top of his dash and it will be a snap for him to r/r. Probably does not lend itself well to trail fixes, glad I just bought a set of folding wheel-chocks. I will pull more gingerly from now on.

Thanks!
Thanks!

I believe the design is an attempt at making the lever self-adjusting.
The lever gets a fresh grab on the drum each time it is released.
It's unfortunate the clutch spring arm, where it is anchored to the lever, is a weak point.
ronjenx is online now   Reply With Quote Quick reply to this message
Unread 09-15-2010, 09:52 PM   #9
mrbodywork
Registered User
2009 JK Wrangler 
 
Join Date: Jul 2008
Location: Key West
Posts: 57
I believe I was reading in the manual of my 2009 Rubicon that the E-brake is NOT self adjusting.

I need to tighten the cable because it has stretched and I'm looking for info on how to do the work myself.

Anyone else had this issue?

Bill
__________________
Key West Mountain Rescue
Protecting Paradise Since 1999
mrbodywork is offline   Reply With Quote Quick reply to this message
Unread 09-15-2010, 10:02 PM   #10
plac
Registered User
2012 JK Wrangler 
 
Join Date: May 2006
Location: CA
Posts: 1,425
Quote:
Originally Posted by mrbodywork View Post
I believe I was reading in the manual of my 2009 Rubicon that the E-brake is NOT self adjusting.
correct. it is not self adjusting. there is no lever that moves the star adjuster. you have to open it up, remove the caliper so you can get to the adjustment hole in the back plate. if you go that far, its just as easy to remove the rotor and adjust the star easily. then get it tight enough so the rotor just has a tiny resistance when turning it.
__________________
2013 VW GTI
plac is offline   Reply With Quote Quick reply to this message
Unread 09-15-2010, 10:09 PM   #11
ronjenx
Web Wheeler
 
ronjenx's Avatar
2008 JK Wrangler 
 
Join Date: Jan 2009
Location: Maine
Posts: 3,941
Quote:
Originally Posted by mrbodywork View Post
I believe I was reading in the manual of my 2009 Rubicon that the E-brake is NOT self adjusting.

I need to tighten the cable because it has stretched and I'm looking for info on how to do the work myself.

Anyone else had this issue?

Bill
The lever is self adjusting, because it gets a new grip on the cable drum each time it is released. The tension spring keeps about 20 lbs tension on the cable after the lever is released, to make up for some cable stretch. The tension spring won't make up for the need to adjust the shoes. Therefore, the brake shoes are not self adjusting.

Applying the parking brake in reverse, and forward, a few time can equalize the left and right sides, making the brake more effective.
Using this procedure, mine went from 5 clicks to hold the Jeep, to 3 clicks to hold the Jeep. That saved me from adjusting the shoes, this time.

This will not work if the lever goes much past 5 or 6 clicks to hold the Jeep.

The shoes can be adjusted without removing the wheel/tire/drum. but it's much easier if you do.
ronjenx is online now   Reply With Quote Quick reply to this message
Unread 09-15-2010, 10:14 PM   #12
McKBrew
Registered User
JK Wrangler 
 
Join Date: Apr 2009
Location: Hayden, Idaho
Posts: 2,743
Another great post. You are the king when it comes to taking things apart.
McKBrew is offline   Reply With Quote Quick reply to this message
Unread 01-17-2011, 09:46 AM   #13
M-Godzwon
Registered User
2008 JK Wrangler 
 
Join Date: Dec 2006
Location: Massachusetts
Posts: 9
The wife just snapped her brake last Friday. Thanks for this excellent post. I was about to climb under the Jeep and start there inspecting cables, but now you've saved me from getting 40 lbs of slush, sand, and salt all over myself.
M-Godzwon is offline   Reply With Quote Quick reply to this message
Unread 01-17-2011, 10:00 AM   #14
1222
Make mine a Jeep!
 
1222's Avatar
2012 JK Wrangler 
 
Join Date: Jul 2007
Location: Henderson, Nevada
Posts: 11,880
Quote:
Originally Posted by McKBrew View Post
Another great post. You are the king when it comes to taking things apart.
Iíll second that.
__________________
1222 is offline   Reply With Quote Quick reply to this message
Unread 02-16-2011, 08:03 PM   #15
ccsaunders
Registered User
2007 JK Wrangler 
 
Join Date: May 2010
Location: Virginia Beach
Posts: 1
I've just finished the parking brake replacement and adjustment. My brake needed to be pulled up all the way and then the ferule on the cable that connects around the pulley on the brake lever snapped. I ordered a new parking brake model 52059887AB. I was able to install it without removing the entire center console. I removed just the storage compartment and was able to use a couple different length ratchets and extensions to remove the old and install the new one without too much trouble. Adjusting the brakes was worse than I'd hoped but still wasn't that bad. I do not believe there is anyway to adjust the star without pulling off the wheel and brake. My brake spoon just couldn't make contact and still have room to rotate the star. I pulled off the rotors so I could see how much (and whether) I was moving the star. The wheel don't spin very easily before adjusting the brake but I turned the star until the wheel noticeably dragged and then backed it off. (This meant I had to put the rotor back on to test.) When I pull the handle I get about 6 clicks until it is good and tight. Could it be tighter? Probably, but it's been so bad for so long I'll take what I can get. Thank you to all the people who've posted information on this topic. You saved me a couple hundred bucks.
ccsaunders is offline   Reply With Quote Quick reply to this message
Reply

Tags
JK Wrangler , parking brake , problem , troubleshoot , wrangler

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.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

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.


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.