Author Topic: rear brake adjustment  (Read 8841 times)

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mattjohnson207

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on: November 19, 2012, 02:47:54 am
Brakes occasionally moaning  (rear)  so I adjusted according to Bareneked's writeup, got the rear wheel locked up, tightened the adjusting nut a little more, it unlocked with some drag, this repeated two or three times. Got  wheel locked, unwound the adjusting nut, same scenario. it was several turns before it spun freely.  Obviously the shoes are not centered. Next step dissassembly?  Matt in Glendale


Arizoni

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Reply #1 on: November 19, 2012, 04:01:59 am
The way I adjust my rear brake is to first loosen all three nuts at the rear.
The large nut and the castellated nut on the axle and the  nut slightly forward of the axle that holds the brake backing plate in position.
I believe all three of these nuts must be loose so that the brake backing plate can move to a centered position.

With these three nuts loosened, I tighten the small adjusting nut on the rear of the brake rod that runs from the brake lever to the brake cam lever at the rear of the bike until the rear wheel is locked up and will not rotate.
This tightening will expand both brake shoes against the inside of the brake drum, centralizing the shoes and the backing plate with the brake drum.

I then tighten the large nut on the axle, the smaller nut on the brake backing plate and then the castellated nut on the axle.

With all of these three nuts tightened, I then loosen the brake rod nut until the wheel turns freely without any brake shoe drag.

After doing this, some people have found it necessary to adjust the brake light switch so it will activate when the break lever is depressed.

That all said, there should be no drag on the rear wheel when the brake lever is not actuated.  There is no single value for the number of turns the brake rod nut must be loosened to achieve this.  It takes what it takes and no more.

With the rear brake adjusted this way I find it isn't the most powerful brake in the world but if I really push hard on the lever, I can lock up the rear wheel.
Jim
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1999 Miata 10th Anniversary


mattjohnson207

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Reply #2 on: November 21, 2012, 04:38:41 am
thanks Arizoni!  for some reason I never knew that, probably why my brakes were so far off!


Yamunotri

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Reply #3 on: November 21, 2012, 06:31:00 am


LarsBloodbeard

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Reply #4 on: November 21, 2012, 06:47:56 am
Very cool video.  Thanks for that.


Blairio

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Reply #5 on: January 30, 2013, 05:51:04 am
At the risk of reviving an old thread, I found a link to this youtube video on the The British Bulleteers Forum:

http://www.youtube.com/watch?v=gHRm_t_8DYE

In essence it seems like the rear brake cam bush is intended to slide on the backing plate to help self-centre the rear brake operating cam.  This means that the two bolts holding the cam bush plate should not be so tight enough to prevent the cam bush plate from sliding. I guess loctite or similar could be used to ensure the bolts don't work any looser than intended.

Before I dismantle my rear brake, has anyone else tried this?

The standard method of centering rear brake shoes involves loosen the big and small spindle nuts and the rear brake pivot nut on the brake side, applying the brake and then tightening everything up with the rear brake still on.

I wonder whether this standard method of centering the rear brake shoes does away with the need for the cam bush plate to slide on the brake backing plate?

Cheers,

Blair


barenekd

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Reply #6 on: January 30, 2013, 05:50:52 pm
The cam bush plate should still slide. No one says the brake shoes are identical. That will push the cam off center a bit.
Bare
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Blairio

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Reply #7 on: January 31, 2013, 12:32:08 pm
Thanks for the response, Bare.  I double checked the rear brake on my bike,  and the cam bush plate is bolted up real tight and painted over.  My bike is a 2012 Electra EFi. is anyone else's bike like this, or did I get a Friday afternoon model?

Cheers,

Blair


ERC

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Reply #8 on: January 31, 2013, 04:23:55 pm
The newer ones don't move like the older ones did.  ERC
« Last Edit: January 31, 2013, 05:46:47 pm by ERC »
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barenekd

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Reply #9 on: January 31, 2013, 05:24:42 pm
Setting the pivot pin (The nut in front of the axle) must be taking care of the problem
Bare
2013 Moto Guzzi V7 Racer
2011 Black Classic G5 (RIP)
I refuse to tiptoe through life only to arrive safely at death
http://www.controllineplans.com