Author Topic: Front brake plate movement  (Read 520 times)

Online a101960

  • Wise & Enlightened
  • *
  • Join Date: Sep 2007
  • Posts: 1062
  • Karma: 12
  • BSA RGS BSA C12
Front brake plate movement
« on: 13.08. 2016 15:50 »
Anyone got a suggestion as to what might be happening ? 8” single sided front brake hub. When the brake is off the brake plate is perfectly flat, however when the brake is applied, as the front brake operating lever is pulled upwards by the brake cable, the brake shoe lifting cam moves outwards in the direction indicated by the arrow, more worrying is the fact that the plate itself flexes and tries to go with it. When I release the brake everything goes back to where it should be. Has anyone else ever had this problem? Or do they all to that sir? I can’t think that it can be a good thing that a casting flexes like that.

Offline morris

  • Wise & Enlightened
  • *
  • Join Date: Aug 2012
  • Posts: 1683
  • Karma: 26
  • Antwerp, Belgium
Re: Front brake plate movement
« Reply #1 on: 13.08. 2016 20:13 »
I don't think that's normal. There's something seriously wrong there. My plunger's HWH brake plate does not move at all in whatever condition.
Does it move when pulling the lever at standstill or only when driving?
Did you change brake shoes recently?
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
Belgium

Offline chaterlea25

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 3526
  • Karma: 49
Re: Front brake plate movement
« Reply #2 on: 13.08. 2016 20:36 »
Hi,
Have you tried centralizing the shoes?
Loosen the pivot nut opposite the brake arm, apply the brake, re tighten the nut while the brake is still applied

John
1961 Super Rocket
1963 RGS (ongoing)

Online a101960

  • Wise & Enlightened
  • *
  • Join Date: Sep 2007
  • Posts: 1062
  • Karma: 12
  • BSA RGS BSA C12
Re: Front brake plate movement
« Reply #3 on: 14.08. 2016 12:17 »
Quote
Does it move when pulling the lever at standstill or only when driving?
Did you change brake shoes recently?
Well, yes, I have recently changed the brake shoes. I noticed this happening when the bike was stationary. I am going out later I will try and check to see if it happens on the move.
Quote
Have you tried centralizing the shoes?
Loosen the pivot nut opposite the brake arm, apply the brake, re tighten the nut while the brake is still applied
Yes John, I have always done that every time I remove and refit the wheel.

Offline coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1181
  • Karma: 6
Re: Front brake plate movement
« Reply #4 on: 16.08. 2016 00:15 »
 As far as I can tell from the picture, nothing should be pushing out at all, normally, when the brake is applied.

 Only a couple things that could be doing it really. The lobes on the brake actuator are not worn square but more like a wedge forcing the brake shoes outward under pressure, or the brake shoes are not cut square where the actuator rides, forcing them out.


 Its weird, but there is not much more in there that I can see that could actually cause outward pressure. *conf*

 "maybe" if the shoes were a little wider than stock, and the brake drum surface was worn or cut so badly as to slope down toward the outside making the shoes want to ride out under pressure but they would have to be really bad...

 Lee
Central Wisconsin in the U.S.

Offline morris

  • Wise & Enlightened
  • *
  • Join Date: Aug 2012
  • Posts: 1683
  • Karma: 26
  • Antwerp, Belgium
Re: Front brake plate movement
« Reply #5 on: 16.08. 2016 13:21 »
I hope it's not that, but in addition to the above, check that the plate hasn't cracked... *eek*
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
The world looks better from a motorbike
Belgium