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Author Topic: Rear Brake Adjustment  (Read 3288 times)

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Offline Dirty Steve

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Rear Brake Adjustment
« on: May 29, 2014, 09:18:44 PM »
Hi all,
I'm trying to adjust my rear brake after replacing the originals with EBCs. First of all, they were a tight fit when I installed them and, as a result, the rear wheel doesn't spin freely even without the brake connected. I can turn it fairly easily with the brake rod loosely connected, but if I try to adjust the brake so I've got the recommended one inch of travel, the wheel completely locks up. Basically I can have a working brake with 3 or more inches of travel, or I can have a completely locked up rear wheel with one inch of travel. And even when it works it still feels mushy.
Are these aftermarket brake pads not engaging evenly, or could I have installed them wrong?
Thanks!
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Offline bjbuchanan

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Re: Rear Brake Adjustment
« Reply #1 on: May 29, 2014, 09:39:51 PM »
The EBC shoes usually require a bit of shaping, in my case I had to hit the edges hard to fit the hub nicely. The better they fit the hub the better the braking. They used to do this as a service, shoe arcing or something like that, idk i'm too young lol. Now you shape the brake with some 120 grit and check over and over til it matches the hub nicely

Don't forget to grease your pivot. Mine was damn near rusted/corroded in place and ended up seizing altogether. This entire time my "firm" feeling rear brake was garbage until heated, cleaned, greased and readjusted. Now it locks up tight like it is supposed to if you jam on it.

Check the line up of the pedal, maybe some adjustment will grab a bit more? KISS
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Offline Dirty Steve

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Re: Rear Brake Adjustment
« Reply #2 on: May 29, 2014, 10:35:53 PM »
Do you think the edges of the shoes on the pivot end are engaging first right now? Is that my problem?
« Last Edit: May 29, 2014, 10:40:23 PM by Dirty Steve »
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Offline flybox1

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Re: Rear Brake Adjustment
« Reply #3 on: May 30, 2014, 09:28:15 AM »
first, chamfer down the leading end edges of the pads, if not done by EBC.

second.  be sure your internal springs are pulling the pads IN and away from the drum faces, and before you put the pads back in the drum, put the lever on and actuate the pads to see that the spread outward and spring back. when they function properly, then insert the cover onto the hub/drum

finally, before locking down your rear axle nut, have an assistant stand down on the brake lever to center the pads in the drum, while you torque the axle nut.   there should be no dragging, even with new pads.
« Last Edit: May 30, 2014, 10:10:05 AM by flybox1 »
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Offline Dirty Steve

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Re: Rear Brake Adjustment
« Reply #4 on: May 30, 2014, 09:45:14 AM »
Thanks to both of you...
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Offline MCRider

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Re: Rear Brake Adjustment
« Reply #5 on: May 30, 2014, 11:30:56 AM »
CB750?

Did you remove the pedal and its actuating lever? For cleaning or whatever?
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Offline Dirty Steve

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Re: Rear Brake Adjustment
« Reply #6 on: June 08, 2014, 12:30:23 PM »
Yes, The origal set up when I got it was a platform for the foot with an aftermarket pedal, like a cop bike. I took that stuff off and found a stock pedal to replace it.
Does anyone know the torque spec for the rear axle?
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Offline MCRider

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Re: Rear Brake Adjustment
« Reply #7 on: June 08, 2014, 04:42:10 PM »
Quote from: Dirty Steve on June 08, 2014, 12:30:23 PM
Yes, The origal set up when I got it was a platform for the foot with an aftermarket pedal, like a cop bike. I took that stuff off and found a stock pedal to replace it.
Does anyone know the torque spec for the rear axle?
The reason I ask is because when the pedal spindle is removed, and the mechanic has never seen how it really goes,  4 times out of 5 it is instaled incorrectly and results in a brake which defies adjustment. Could be your problem. Ill need pictures of the pedal spindle and where the part with the pulling bracket contacts the swingarm.

This problem has occurred many times here, but before your time I expect.

AS to torque of rear axle nut: 57.8 to 72.3 = real tight.  IF everything is installed correcty, you cannot overtighten the rear nut. If tightening the rear nut results in ANY symptom untoward, some thing is seriously wrong.

http://www.salocal.com/sohc/tech/torquetable.htm
« Last Edit: June 08, 2014, 04:44:55 PM by MCRider »
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1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
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Offline Dirty Steve

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Re: Rear Brake Adjustment
« Reply #8 on: June 10, 2014, 09:32:38 PM »
Thanks for your time on this...
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1975 CB750K5 with stock airbox, exhaust et al...

Offline Dirty Steve

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Re: Rear Brake Adjustment
« Reply #9 on: June 10, 2014, 09:36:08 PM »
Brake shoes...
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Offline MCRider

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Re: Rear Brake Adjustment
« Reply #10 on: June 11, 2014, 05:55:39 AM »
Quote from: Dirty Steve on June 10, 2014, 09:32:38 PM
Thanks for your time on this...
It loks OK from this angle. What we're loking for is that the tip of the lever where the pull rod attaches is bewteen the engine and the swingarm tube. Yours appears to be.

A shot of the pedal showing the end of the brake pivot woul clinch the deal. What we're loking for there is that the dot on the brake pedal aligns with the dot on the end of the brake pivot shaft.
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Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline MCRider

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Re: Rear Brake Adjustment
« Reply #11 on: June 11, 2014, 05:56:21 AM »
Brake soes look fine. Not usually a source of the problem.
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Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline Dirty Steve

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Re: Rear Brake Adjustment
« Reply #12 on: June 11, 2014, 01:54:04 PM »
I tried to send this last time but couldn't pull it off...
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Offline madmtnmotors

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Re: Rear Brake Adjustment
« Reply #13 on: June 11, 2014, 02:08:59 PM »
All that's left, and what MCRider is referring to, is to be sure the rear brake arm (that mounts on the splined shaft at rear brake plate) is indexed correctly. There should be a punch mark (a little dot) on both the splined shaft and the rear brake arm too. These two dots should line up.
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Offline MCRider

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Re: Rear Brake Adjustment
« Reply #14 on: June 11, 2014, 04:20:20 PM »
yEAH ^^

Looks like your one spline off. Probably not enough to cause your problem. The arm on the rear wheel has the same indexing punch marks. Might as well make sure they are right, before messing with the adjustment more.
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1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline Dirty Steve

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Re: Rear Brake Adjustment
« Reply #15 on: June 15, 2014, 04:08:46 PM »
MCRider, Flybox, BJbuchanan, Mtnmotors et al...I finally got around to trying on the old shoes, which still had plenty of pad left but are 40 years old, and it all works like it's supposed to. The EBCs were not uniformly thick, causing the spongy braking and, somehow, making it so the more I tightened the rear axle, the harder it was to turn the wheel.
The old brakes were contaminated with a little bit of grease, but my friend said a little sanding and cleaning with rubbing alchohol would take care of it. It brakes strong now, so I'm satisfied if no one thinks the contamination issue is a problem.
Thank you all for your help!
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Riding motorcycles will make you a poet. Working on them will make you a philosopher.

1975 CB750K5 with stock airbox, exhaust et al...
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