Author Topic: back brakes locking up again...  (Read 17118 times)

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Ducati Scotty

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Reply #15 on: March 20, 2014, 04:23:14 pm
All the other stuff, the roo hit, the damage to the backing plate, could have contributed but when you took it apart and found the swingarm was straight it seemed less likely.  You had the hub apart multiple times.  If that was it I think you'd have seen it one of those times.  This sounds like a more likely option.  I really hope this solves it all.

Scott


suitcasejefferson

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Reply #16 on: March 21, 2014, 12:31:25 am
I have seen this happen on both disc and drum brakes. The pads/shoes don't bite at first, then they lock up. Something is causing the friction level between the pads/shoes and disc/drum to change during brake application. I have no idea whether this has anything to do with your problem or not.

Something else I haven't seen mentioned. Is the brake drum completely round? And does the radius of the shoes match the radius of the drum? Some weird things can happen if the drum is out of round, or if the shoes are only touching the drum at the center or just the ends of the shoes. This is one of the issues I have always disliked about drum brakes. It can be almost impossible to get a perfect match between the shoes and drum.
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Sectorsteve

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Reply #17 on: March 21, 2014, 10:29:04 pm
its still happening....im thinking my only option is to renew the whole ******* back end...


gashousegorilla

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Reply #18 on: March 21, 2014, 10:59:21 pm
 Steve..... Steve o'........ Dude !  :o  ;)   How are you unlocking the brake when it happens ?   After it happens...... HOW does the rear wheel and brake assembly look ?   Does it still look like the alignment is good and how you left it ?  Or does it look screwed up afterwords ?
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


Sectorsteve

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Reply #19 on: March 23, 2014, 03:50:54 am
everything is looking sweet and aligned. i have to undo the brake nut on the rod a little to free the wheel afterwards. ive been too scared to really hit the back brake hard for fear of bending everything. so when these little lock ups happen they are little ones. the next thing to check is the pedal end. its a bit loose up there, but honestly i cant really see how that would cause it.


Arizoni

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Reply #20 on: March 23, 2014, 04:37:14 am
Hmmmmm.

Loosening the brake adjustment allows it to unlock?

Is it possible you have the adjustment set too tight?
Personally, I like my rear brake to start to work with about 3/4 of an inch of pedal travel but when I first got it the dealer had adjusted it so it didn't do much unless I moved the pedal at least 1 1/2 inches.

With this in mind, how far do you have to move the rear brake pedal to get it to start to get hard to push?
Jim
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1999 Miata 10th Anniversary


GreenMachine

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Reply #21 on: March 23, 2014, 03:01:19 pm
With the bike up on the center stand, does the rear drum brakes lock up with just spinning the tire and depressing by hand the pedal vice taking it down the road ?
Oh Magoo you done it again


gashousegorilla

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Reply #22 on: March 23, 2014, 03:59:30 pm
everything is looking sweet and aligned. i have to undo the brake nut on the rod a little to free the wheel afterwards. ive been too scared to really hit the back brake hard for fear of bending everything. so when these little lock ups happen they are little ones. the next thing to check is the pedal end. its a bit loose up there, but honestly i cant really see how that would cause it.



  Not to state the obvious...... but that spring should have no problem pulling that rod back  when you release the pedal. There is a lot of tension in that spring, or should be. By loosening the nut, your making it easier for that spring to pull the rod back.  Sounds like something may be binding and or bent,  from that spring/ arm, through the rod to the pedal.  I no longer have the stock set up, so I can't look. But is it possible that the pedal travel  adjustment is sooo loose, that you are getting it into a position... down so far. That the rod winds up straight, binds and can't return?
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


High On Octane

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Reply #23 on: March 23, 2014, 04:04:10 pm


  Not to state the obvious...... but that spring should have no problem pulling that rod back  when you release the pedal. There is a lot of tension in that spring, or should be. By loosening the nut, your making it easier for that spring to pull the rod back.  Sounds like something may be binding and or bent,  from that spring/ arm, through the rod to the pedal.  I no longer have the stock set up, so I can't look. But is it possible that the pedal travel  adjustment is sooo loose, that you are getting it into a position... down so far. That the rod winds up straight, binds and can't return?

+1

How far do you have to push the pedal down for the brake to engage?
2001 Harley Davidson Road King


suitcasejefferson

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Reply #24 on: March 23, 2014, 04:28:09 pm
I always adjust rear drums by putting the bike on the centerstand, and spinning the rear wheel, while slowly tightening the adjusting nut, until I feel slight resistance, then I back off just enough that the resistance is gone. I like as little play in the rear brake pedal as possible.

I would check that spring, and the whole linkage for something that is binding. It may not be in the actual brake at all.
"I am a motorcyclist, NOT a biker"
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gashousegorilla

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Reply #25 on: March 23, 2014, 05:20:29 pm
I always adjust rear drums by putting the bike on the centerstand, and spinning the rear wheel, while slowly tightening the adjusting nut, until I feel slight resistance, then I back off just enough that the resistance is gone. I like as little play in the rear brake pedal as possible.

I would check that spring, and the whole linkage for something that is binding. It may not be in the actual brake at all.

  +1   They're  COULD or SHOULD also be a pedal stop screw to adjust pedal height. I would imagine, if it is set where the pedal is TOOOO far down..... Then the rod is adjusted, the rod may bind.
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


suitcasejefferson

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Reply #26 on: March 23, 2014, 07:15:48 pm
My 2013 does have the pedal stop screw. The spring is also pretty strong. I loosened the brake rod adjustment nut so there was too much play, pushed the pedal down all the way, released it, and it immediately snapped back against the stop screw. Readjusted it correctly.
"I am a motorcyclist, NOT a biker"
"Buy the ticket, take the ride" Hunter S. Thompson


gashousegorilla

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Reply #27 on: March 23, 2014, 08:01:48 pm
 Good test !...... Damn, if doesn't sound like that spring is not hooked in on one side and un- tensioned too. 
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


Sectorsteve

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Reply #28 on: March 23, 2014, 10:55:42 pm
I'm tightening the nut tight until the wheel is locked up then I back off til the wheel turns freely.

The spring , shoes, & all brake components are new, however the new cam bolt thread is much shorter and cross threaded that opens the shoes. I need to re thread that bolt. In the meantime of lock tited it and its set but not ideal.
I must say some of the items I've been buying from hitchcocks have been substandard. I replaced many nuts in bolts etc that were pretty rubbish. Washers bending easy , the replacement cam bolts and nuts are soft and a horn I bought from them didn't work.
I'm going to focus on minimising movement down near brake pedal and also the brake arm.


Hmmmmm.

Loosening the brake adjustment allows it to unlock?

Is it possible you have the adjustment set too tight?
Personally, I like my rear brake to start to work with about 3/4 of an inch of pedal travel but when I first got it the dealer had adjusted it so it didn't do much unless I moved the pedal at least 1 1/2 inches.

With this in mind, how far do you have to move the rear brake pedal to get it to start to get hard to push?
[/quote]


GreenMachine

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Reply #29 on: March 24, 2014, 02:39:55 pm
I find adjusting the rear brakes on the center stand is a "get you in the ball park" setup ..Afterwards ,  I go for a scoot around the block and take a small wrench with me to re- adjust the play and feel of the rear  brake function...It should require just a nominal bit of pedal play vice having to mash down to effectively stop the bike at a moderate rate of speed...

When you start talking about cross threaded pieces in a braking mechanism, you're going to have problems...The drum brake system on the enfield is simplistic but requires all the pieces to be aligned and matched to properly activate in a correct manner....Sorry about the substandard parts but it would be best if you could replace any piece that is suspect concerning the drum brake...You'll fix it sooner than later and find it was a inexpensive fix or operator error. The bottom line is that safety comes first and braking is your first line of defense..... GM
Oh Magoo you done it again