How do I know the parking brake is properly adjusted?

6716

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Jul 24, 2012
833
So did rear pads and rotors yesterday. I've never paid attention to the parking brake before. The shoes look like they are in pretty good shape, or at least there looks like there is still lots of material there compared to pictures of new ones.

The driver's side rotor was a bit challenging to remove -- I imagine that had to do with the parking brake? I convinced the rotor to come off with the rubber mallet, and the new rotor went on easily.

I see there is a video out there for adjusting the lever, and I have Mooseman's manuals and I've read over the parking brake section.

But what should I expect from the parking brake? Should it hold the truck on a hill in neutral?

It "works" in the sense that I can pull up the lever and the light comes on ... but I'm not sure what to think of how well it holds. Maybe it's fine. But I don't know how to know, y'know?
 

Blckshdw

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Nov 20, 2011
10,747
Tampa Bay Area, FL
Mine holds my EXT steady when idling in gear. :twocents:
 
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Matt

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Dec 2, 2011
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:iagree: It should hold it when in gear at idle. If it don't, readjust.
 
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Mooseman

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Dec 4, 2011
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Ottawa, ON
The manual says to use measuring calipers and so on to measure the drum and then the shoes and adjust. Most don't have that. Here's the method I use:

1. Put on the disc/drum, check for drag. Pull the lever a couple of times to center the shoes inside the drum.
2. Pull the disc and adjust the shoes a little by turning the star wheel.
3. Put the disc back on and check for drag
4. repeat 2 and 3 until a slight drag is felt
5. pull/lower the lever a couple times again to center the shoes
6. If the slight drag is still felt and the lever had a solid feel mid way, you're done (or repeat the other side)

One thing if you are reusing old discs, if the drum is rusted you should wire wheel the inside of the drum just to remove it. Another thing, if replacing the shoes, be sure to have one side with the shorter shoe towards the front and the other side have the longer shoe on front.
 

6716

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Jul 24, 2012
833
Well, at warm idle / 600 RPM, the parking brake holds the vehicle steady on flat ground. So on that measure I'm not too far off.

Mooseman, thanks for the tip. My challenge was that neither rear wheel would spin for me to check the drag. Only one was up at a time, maybe that was it. Or was it that the shoes were waaaay tighter than a "slight drag"?
 

Mooseman

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Dec 4, 2011
26,026
Ottawa, ON
It is harder because of the rear axle. There is a little wiggle room of the disc rotation on the studs and with just that I cal tell if there is drag. You disc may be rusted to the axle hub.
 

Sparky

Member
Dec 4, 2011
12,927
I'm trying to figure out what that does. I must be tired as I have no idea.

Generally, if the parking brake holds the vehicle when on an average hill in neutral I call it good (similar to holding with it in drive at idle). I wouldn't necessarily expect it to hold on a really steep hill though.
 
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Mooseman

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Dec 4, 2011
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Ottawa, ON
That's the tool the manual recommends using. You measure the drum then adjust the shoes to fit minus a little. I haven't seen it available in parts store here, probably because nobody uses it.
 
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mrrsm

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I'm uncertain if these Printed Instructions and Images on my 4th Gen F-Body New Emergency/Parking Brakes are close to the appearance and thickness of the ones designed for the GMTs... but I think the principles and the idea is probably close enough to give it a look.

As for adjusting them to spec... pretty soon... I am going to get my chance. It occurs to me that since I can do this as a test off of the car with just the two Four Bolt Rear Wheel Mounting Brackets and the two Rear Brake Disks... I should be able to put them temporarily together with a large vice gently holding the disk upright and then crawl all over the adjustment process with my old Sony Cyber-Shot camera and document what happens and to post the images back here.

But of course... this is contingent upon the idea that the GM Emergency Brake designs for the GM Trucks and SUVs have the same essential hardware as the F-Bodies... albeit probably a bit more beefed up. I don't have the Vernier Calipers yet.. unless my Stainless Steel Digital I/O calipers would expand to 200 MM or so... I will check.

FWIW... .Here you go...
 

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Sparky

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The parking brake on the fbody and the GMT360 are almost identical in function.
 
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mrrsm

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Cool Beenz... I'm about to start the final reconditioning of the Rear Brake Hardware today and will document what happens when I glomm the parts together in the vice and and report back on the progress tomorrow.
 
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Wooluf1952

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Nov 20, 2011
2,663
Milwaukee, Wisconsin
That's the tool the manual recommends using. You measure the drum then adjust the shoes to fit minus a little. I haven't seen it available in parts store here, probably because nobody uses it.

That's it. It works like a giant calipers. You set one side to the size of the inside of the parking brake drum. That automatically sets the opposite side to the correct size for the parking brake shoe.
 
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6716

Original poster
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Jul 24, 2012
833
The rotors were rusted in the drum side, and the shoes definitely had a layer of rust dust on them. I think that was a lot of why I was questioning the performance, the rust was inhibiting the bite. The brake just seems in general to perform better with new rotors ... go figure.

Now I wonder if the driver's side shoe is a little tight, and that was why the rotor was reluctant to come off. Can I adjust that with that little dial?
 

DAlastDON

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Apr 6, 2014
5,550
Kentucky
That is what the dial is for. Adjust it until there is minimal drag and back it off just a hair more on both sides.
 
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6716

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Jul 24, 2012
833
Is down looser or tighter with that dial?
 

Mooseman

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Dec 4, 2011
26,026
Ottawa, ON
IIRC, it's normal rotation so up for tighter.
 

mrrsm

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That is what the dial is for. Adjust it until there is minimal drag and back it off just a hair more on both sides.
This Digital 8" (200mm) Vernier Calipers device for $32.00 is the tool of choice here:

http://www.amazon.com/Simtyso-Precision-Electronic-Stainless-Micrometer/dp/B013HY6YYQ?psc=1&SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-ffhp-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B013HY6YYQ

Over the next few days... I am tearing apart the Rear Emergency Brakes on the '93 Z-28 for a complete rebuild and I will add to the just attached images more information and imagery to DE-mystify their simple but elegant design and function. This is contingent upon the arrival of a pair of replacements ($17.00 + $3.00 S&H via eBay) for the old, ruptured and useless Black Rubber Weather Proof Boot that surrounds the Drop Forged Steel Actuation Arm that slides into the Slotted, Notched Rotary Adjustable Dual Cam Coupler that literally gets very tightly "pinched" together by the lower arms (fingers?) of this semi-circular shoe assembly. The new Rubber Kit comes with the some new 8MM OS-#2 Phillips Screws as well. The other link to eBay shows the components and additional images of how the Parking Brake Adjuster looks and functions with its new parts disassembled.

http://www.ebay.com/itm/1998-2002-Camaro-Firebird-Parking-Brake-Boot-Kit-2-boots-OEM-PBR-4-screws-/111685725126?fits=Model:Camaro&hash=item1a00fcebc6:g:biggrin:qwAAOSwyTZUWjff&vxp=mtr

http://www.ebay.com/itm/Trans-Am-Pa...wEeFVRkL8&vxp=mtr&rmvSB=true&tag=gmtnation-20
 
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mrrsm

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Okay... I finally got caught up enough with the POR-15 Paint Project to start working on re-building the Emergency Brakes and memorialize every aspect of that procedure here as well if it holds further interest beyond just measuring the size of the "C" Shaped Emergency Brake Drum with Vernier Calipers. I decided to get this one because it is more than satisfactory for this and many other jobs with greater than 4"-6" common dimensions. I am including images of the product description as well as the instructions for its use so you can have that handy in the future.

http://www.amazon.com/dp/B013HY6YYQ/?tag=gmtnation-20

My diurnal sleep cycle is all "scrabnoid" right now... so I will probably be working on the E-Brakes and installing the new parts (including the Rubber Armature Boots from a 2002 4th Gen F-Body as they no longer manufacture the ones for the 93-97 flavors)... so we'll see if they can be made to work. I'll post progress images back here from time to time as I make headway for the rest of today. Here are some images of the Vernier Calipers in action:

EDIT:

Sorry about that... The SIZE RESTRICTIONS HERE REQUIRE THAT HIGH-DEF IMAGERY MUST GET SHRUNKEN FIRST.... But unfortunately... my Debian 8 Linux Batch Converter called "Converseen" decided not to work...and after fiddling around with it trying to figure out WHY for about hour... I just decided to park these images of the Vernier Calipers on my Photobucket site:

http://s557.photobucket.com/user/60...INEREPAIR/TRAILBLAZEREPAIRTOOLS?sort=3&page=1
 
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Chickenhawk

Member
Dec 6, 2011
783
It would be interesting to compare the vernier calliper method with the old school method I use. I back off the adjustments just until the rotor slips on and off easily, then I tug up and down on the parking brake handle a few times. I then lift it two clicks. I then tighten the adjuster until it just barely fits on with a bit of rubbing. I then drop the parking brake handle to double-check it is now free, and I know that it will just start to make contact in the first two clicks.

I use this method so I can get both sides nearly the same. The only downside is that it doesn't work if the inner drum part of the rotor is worn and there is a ridge.

Once everything is assembled, I make sure it will hold in drive at 2000 RPM, and then I find a quiet snow-covered or gravel road and tug on the brake at 30 KPH. If both sides are the same, it should stop relatively straight. (There will always be a bit of sideways movement because there is no way to get both sides exactly perfect, nor are they designed to stop the vehicle anyway except in an emergency.) I then check out the skid marks. As long as there are two skid marks and they start at relatively the same spot, I am done.
 
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mrrsm

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After mounting all the cleaned up and "BEENIB" (Brand New In Box) Brake Stuff back on the 4 Bolt Bracket and Tin Shield ... I'm going to sling a Brand New Rear Disc inside of a cardboard sandwich to protect the brake surface and then clamp it up into The Oldest, Most Gnarly Looking Vise in existence, Then I'll slip the "C" Drum inside the race and just adjust and rotate the Drum around until it won't move... then make some measurements to document its MM width at that extreme. I'll gradually back off on the adjustment until I can just barely pull it from inside the disc and measurement again. That will give an AC-Delco OEM Drum to Race Baseline.

On the third go around, I'll loosen and adjust BOTH Rear Combos just enough to completely clear the inner races and THAT will be the condition they stay in until after everything is back on the car. Then I'll sit bin the Driver's Seat and see how much the handle moves upwards when I pull on it and let the button go to freeze its hold postions. The Z-28 idles at only 600 RPM ... so I'll park it on a clear spot, start the motor...set the E-Brake and gradually raise the RPM to around 1,500 and see if it holds. If it does... I'll put the shifter in "D" and see if it still behaves. If it doesn't move... I'm done... but if it gets even a slight case of "The Creeps"... I'll park it...elevate and Jack Stand the rear wheels and adjust both sides accordingly. Done!
 

mrrsm

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Good Morrow... One and All...

Please consider what follows as a sort Text & Visual "How to Re-Build the 1998-2002 Chevrolet Camaro-Firebird LS1 Emergency Brakes: Class-101" as its doubtful that the ways and means for preparing how to tear this assembly down and re-building it correctly versus paying nearly $200 Per Wheel for Brand New E-Brake Hardware has ever been done to the scale of the included minutiae. As such the "Follow-The-Steps-In-The-Imagery" method of learning consists of 75 Separate Photos... I had to park these images on my Photobucket.

If you are intent upon doing this properly... Try to obtain AC-Delco or Delphi components when and where possible. It will be necessary to submerge the entire set into a pan with enough of a powerful De-Greasing agent that it will dissolve perhaps as much as 20 years of dirt and corruption. But prior to dropping the assembly into the pan... you must first remove the "C" Drum by unfastening the Spring Clamp holding the inner race of the Black Metal Inner Hollow Drum Bracket at the top of the unit. Then ...watch your hands and fingers carefully here... while pushing the "C" Drum downward, observe that it will easily slide down and free from the two contact ends off of the Lever Pins Pads at the bottom of the unit. Don't re-use this "C" Drum and instead, it should be discarded in a responsible manner as it represents a present danger from Mesothelioma Lung Disease should the Old E-Brake Dust on it become dislodged and inhaled.

After soaking the E-Brake assembly for a while, unscrew or undo any other components attached to the Hot-Dipped- Zinc-to Cast-Iron base and then begin scrubbing the base and components either in a heated Ultra-Sonic Machine such as the Umaxx or obtain some large Brass Bristled Brushes and some Green Scotch-Brite along with some Dawn Dish Soap. Diligently scrub each and every part free of all dirt, crud, corrosion and rust and then rinse each item individually in Very Hot water and pat dry them with paper towels while they are still warm.

You will use up quite a few Paper Towels during this job, so keep the roll handy. Start by working on the base to clean out every last crevice of old grease, dirt and rust after removing the "Tin Shield" and setting it aside. Use a screw driver to dig and probe around inside the heavy cast cylinder and remove any debris or junk lodged therein. After you have ensured that all your hardware is spanking clean, begin by slipping the drop-forged Emergency Brake Cable Armature into the body of the cylinder. When you later re-install the Machine Screws with the Combination Hex and #2 Phillips features into the ancillary attachments... put a drop of Red Thread Locker on them and snug them tight.

There is only one way this item will insert, so be patient and look at the re-assembly images attached here for guidance. After that, install the new Weather Boot onto the base with the thin tin hold down oval ring with the two end screws as this rubber item will hold the armature essentially right where it needs to be for the ease of the rest of the build. The rest of this How-To is all visual....Please...Look at the pre-assembly layouts and lubrication imagery and simply do what you see in the photos as they are a good guide to ensure that everything goes back correctly as follows. The last few images here show how the lever Armature actuates the "C" Drum by uniformly expanding it outwards to make contact with the smooth inner race of the Rear Disc Brake to stop or hold the vehicle from moving by means of internal friction:

The next installment will show this E-Brake Unit being manually pre-set with Vernier Calipers and adjusted with the use of a flat-bladed screwdriver. Then the E-Brake assembly will be inserted into Rear Brake Disc bench mounted in a large vice and "image-documented" in the like manner as follows:

http://s557.photobucket.com/user/60dgrzbelow0/library/1993 CAMARO Z-28/93Z28SUSPENSIONANDBRAKES?sort=2&page=1
 
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Mooseman

Moderator
Dec 4, 2011
26,026
Ottawa, ON
The only downside is that it doesn't work if the inner drum part of the rotor is worn and there is a ridge.

When I had old school drum brakes to replace the shoes and keeping the old drums, I would use a die grinder to get rid of the ridge.
 
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Chickenhawk

Member
Dec 6, 2011
783
Yup! Been there too.

On the other hand, one could safely say that if there was too much of a ridge on the inside of the rotor, something is seriously wrong. Technically, unless there was an emergency, there should be no wear whatsoever, as the only time the parking brake is applied is when the vehicle is ... well, parked.

This is why I like to test out the brake every now and then, with an application that locks up the rears on a snow-covered or gravel road. I make sure it locks up the rears at 30 KPH, plus I see if they are both relatively even. This also cleans off the shoes and drums without causing undue wear. I do this every year when I put my winter tires on.
 

mrrsm

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Okay... I've performed the process of taking the Basic Measurements of the relationship between the Outside Diameter of the Emergency Brake Drum "C" Pad and the Inside Diameter of the Inner Race of a Brand New AC-Delco LS-1 Rear Brake Disc at two separate locations on both and arrived at the following:

Inside Rear Brake Disc Emergency Brake Drum Dimension: (Two Samples...90 Degrees apart)
189.45 mm and 189.76 mm

Outside Emergency Brake Drum "C" Pad Dimension: (Two Samples ....90 Degrees apart)
189.30 mm and 189.189.31 mm

Very snug in this instance as the Test Items are all NEW. Nonetheless... These dimensions will vary wildly due to variations in manufacture and the fact that the entire brake assembly is NOT manufactured as ONE UNIT. The other aspect of this is that the actuation by cable lever appears linear because one central cable actuates two other cables to pull on two levers to make the E-Brakes function.... but the effect upon the pad and drum is more akin to blowing up one balloon section inside of another rigid balloon acting by the expansion of its VOLUME inside the race of the Rear Brake Disc... so technically... these baseline measurements do not mean much.

Consequently, I chose to make some Linear Measurements of the the position of the Lever Armature-to-Base distances in order to determine its change of position from static... to the point where the "C" Drum expands and finally makes contact with the inner race. Just as the differences between the above listed measurement were very minimal... I found that with Brand New Hardware and with the Adjustment "Star" Lock Screw being set to "Zero"... the resting dimension of the inside top of the curve in the lever where the cable makes contact was 29 mm in height.

Conversely, when the lever was actuated to its stopping point as though it were being made to move by lifting the Parking Brake Handle... the Action Dimension expanded to a height of 32 mm. This 3 mm difference may not seem like much, but it is sufficient to keep the Brand New Hardware interface from being neither too loose to have any effect if the E-Brake handle were yanked up under the Driver's Right Armpit for Emergency Stop... nor so tight as to allow the "C" Drum to put a substantial drag and an uninvited "bite" on the inner race of the rear Brake Disc E-Brake Drum.

The last thing to understand is that the E-Brake Adjuster is inaccessible when the two components are mated together and so any follow-up adjustments must of necessity be done with the Rear Brake Disc removed for a Trial and Error method to bring their relationship back in line with what you see here for a baseline...with the added wear complicating things. Therefore, it is recommended that a light coating of anti-seize compound be applied between the 5 Stud Outer Hub Flange and the inner contact area of the Disc Brake surfaces on all Four Wheels.

I have updated my Photobucket with the images that will further elucidate the matter:

http://s557.photobucket.com/user/60d...?sort=3&page=1
 
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