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Old 11-19-2012, 03:41 PM   #1
jrapose
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Default Brake centering tool

I have a question about using the brake centering tool.... is it needed just to set the brakes so the drums can be installed ? Once the drums are installed I thought the brakes would center themselves.

Or have I just been lucky installing shoes all these years ? Never used one of these tools...are they really needed.

Joel
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Old 11-19-2012, 03:48 PM   #2
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Default Re: Brake centering tool

Unless you have a floater system, they don't center themselves. Everything that I have read say's that it is a very good idea. Required.....I dont know. I don't take any chances with brakes.
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Old 11-19-2012, 04:02 PM   #3
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Default Re: Brake centering tool

Even if you have the shoes arced to match the drum size, the odds of them being centered are remote. They will equalize on the rears but not on stock fronts.

It's important to note that there is more to a proper centering tool than most folks realize. The centering tool must be a micrometer of sorts OR have the ability to be sized to the drum that will be used. For example, if your drum is .043" over then the centering tool must be set to that size. If the centering tool is set too large or too small when setting up the shoes then they will no longer be centered when you properly adjust the adjusting wedge to match the drum.

If you go through this exercise correctly just one time I suspect you will be amazed what you find.
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Old 11-19-2012, 04:10 PM   #4
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Default Re: Brake centering tool

Marco, Not sure I understand your point. If you center the shoes around the axle, and the drum braking surface is by design centered on the axle, how does it matter if the drum is oversized?
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Old 11-19-2012, 07:01 PM   #5
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Default Re: Brake centering tool

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Originally Posted by Will N View Post
Marco, Not sure I understand your point. If you center the shoes around the axle, and the drum braking surface is by design centered on the axle, how does it matter if the drum is oversized?
my confusion is more fundamental than that....where exactly is there any adjustment provision within the front braking mechanism?
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Old 11-20-2012, 10:41 AM   #6
Marco Tahtaras
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Default Re: Brake centering tool

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Marco, Not sure I understand your point. If you center the shoes around the axle, and the drum braking surface is by design centered on the axle, how does it matter if the drum is oversized?
It's tough to describe all the variables with the geometry. In simple terms using a front brake as an example. Lets say you center the shoes at .040" smaller than the drum. What is the first thing you do after installing the drum? You go to the top of the backing plate and crank in the adjusting wedge until you get a "slight drag" on the brake. What you have done is expanded the TOPS of the shoes a bit over .020" while the lower end or "toe" of the shoes remain fixed on the tracks. You have now enlarged the circle UPWARD which raises the center of that circle. That means if you've bent the roller tracks, or better yet used custom roller pins to set the height or vertical center of the shoes you've just undone that work.

Now it IS possible to get close with a cheap centering tool as long as it holds it's setting. Start by installing the brake drum completely. Next, adjust the wedge until you have a very slight drag. Remove the drum and adjust the centering tool to the highest point on the shoes where drum contact occurred. Ideally that would be the heal of both shoes but more likely it will be the heel of JUST ONE.

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Old 11-21-2012, 07:43 PM   #7
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Default Re: Brake centering tool

I've read this thread a few times, and I think I "get" the concept. In Marco's most recent reply, you explained what most likely we'll find. How do you correct and center the shoes if in fact the heal of one is higher? Is the only way to sand the high spots with a tool I don't have? Do most people just have the shoes arched and get by without the centering? I have just removed all my brakes and backing plates and am getting the shoes religned and arched. I really appreciate all the insight from you more experienced Barn guys.
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Old 11-19-2012, 07:08 PM   #8
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Default Re: Brake centering tool

Borrowed this photo from *Afordman31*, thank you..This is a top view, the "wedge, with square head" is the adjustment. To the right side of the photo..

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Old 11-19-2012, 07:32 PM   #9
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Default Re: Brake centering tool

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Borrowed this photo from *Afordman31*, thank you..This is a top view, the "wedge, with square head" is the adjustment. To the right side of the photo..

Ohh jeez, ....the train has just "derailed"!!
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Old 11-19-2012, 07:47 PM   #10
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Default Re: Brake centering tool

If your drums are turned to a larger diameter than the shoes, then they will contact in the center of the arc, not out towards the ends. This means you have a much smaller contact patch than you should. I.E. less brakes. Once the shoes have been ground to the proper dia. they need to be centered in the drum. Once centered then they can be adjusted in our out with the wedge. This only affects the drag or preset of the shoes before they are actuated. This is an exaggeration but think about it like this.... If you have a 14" rim in a 15" tire it’s only going to contact the tire's lip in one spot, not all across like it should. Even then the spot could be high or low and not on the centerline. Here is a pic someone posted here before that I borrowed. I have Barrett equipment, but this will get you by....
Good Luck
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Old 11-19-2012, 08:00 PM   #11
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Default Re: Brake centering tool

If you install Flat Head Ted's floater kit the front brakes will then automatically center. The rear brakes only half center. In addition to Flathead's floaters installed in the rear adjusters, he also provides what he calls "pins" that replace the rollers that slide on the roller tracks. For each rear wheel the pins are a pair that are a mirror image to each other. Instead of a roller there is a four sided eccentric with a 1\16" difference to each side. By selecting a given side you center the other half. You need a centering tool to accomplish this. Bratton sells one that will do the job. Page 156 in their catalog, part number 2695, $44.00.

According to some literature I have seen the centering of the original rear brakes is supposed to be accomplished by bending the roller tracks up or down.

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Old 11-19-2012, 08:06 PM   #12
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Default Re: Brake centering tool

This is the one I use.

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Old 11-19-2012, 08:11 PM   #13
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Default Re: Brake centering tool

You center the front by bending the flats of the roller track up or down.
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Old 11-19-2012, 09:07 PM   #14
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Default Re: Brake centering tool

Brake shoe sizer and centering tool

This tool can be set to the radius of the drum and then used to check the shoes on the wheel and center them too. The $99 this guy is asking is too much money for it but it is a solution.

The best tool for the A is the Barret Brake Doktor. This attaches to the axle and sands the shoes to size on the car. This means the shoes will also be centered to the axle.
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Old 11-19-2012, 09:12 PM   #15
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Default Re: Brake centering tool

Kevin the only problem I see with the brake doctor is if it sands the shoes to fit the drums its not really centering them. It would cause one shoe to wear out before the other.
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Old 11-19-2012, 09:43 PM   #16
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Default Re: Brake centering tool

The tool is attached to the axle with the shoes mounted. You then turn the tool around as the disk sander sands the shoes to diameter. The shoes have to be centered as it is swinging around the axle.

The differential thickness is not much unless you put some way off hardware on the shoes. Besides, how many drive their car enough to wear out the shoes? Most cars are not driven enough to wear the brakes to the drums in less then a few years. This makes getting the center and diameter of the shoe even more important from the start. Otherwise you may take years to get full braking as the shoes wear to fit the drums.

It is a royal pain in the butt to make all the brake parts give you a centered fit to the accuracy you get with the Doktor tool. Short of getting all NOS brake parts the best brakes will come from properly using the Doktor.
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Old 11-19-2012, 09:57 PM   #17
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Default Re: Brake centering tool

But if the shoes are arced to fit the drums, then centered with a centering tool, doesn't that take care of the possible oversized drum problem?
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Old 11-19-2012, 10:12 PM   #18
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Default Re: Brake centering tool

This is the shoe grinder.

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Old 11-19-2012, 11:14 PM   #19
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Default Re: Brake centering tool

I am going to copy Craig's econo-tools he made and give it a try.....now that it has been explained I think I understand........all these years I have always had hydraulics and did not experience the fun of mechanical brakes....and all the little tricks to them....ie. that darn emergiency brake return coil spring nightmare.

Thanks Guys
Joel Rapose
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Old 11-19-2012, 11:22 PM   #20
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Default Re: Brake centering tool

700rpm, "yes" is the answer.
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