Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: billdn on February 17, 2021, 05:50:02 PM

Title: rear brake puzzle
Post by: billdn on February 17, 2021, 05:50:02 PM
After replacing rear brake pads and respraying tensioner arm and rear brake rod back to black - were polished but kept getting mild rust. I'm having a devil of a job getting the rear brake pedal to actuate the switch without having it so tight that the back wheel is locked up before it's operated!
It all worked when I took it off!
So having checked the archive posts I learnt that dots on pedal and shaft for brake pedal should be aligned- check.
 Getting the footrest on is a fiddle but doable. the problem arises that when the brake rod is connected to brake arm the wheel is locked up , even with above in right place, and obviously spring on cam that operates brake light cant move and operate the rear brake light.
I've tried repositioning and pre tensioning the brake rod arm ,by pushing the unsecured end from the brake rod arm to push spring up prior to fitting pedal but it all ends up with brakes full on or fouling the exhaust collector box.
it all sound a bit protracted and I know I'm missing something simple but for the life of me I can't work it out. if I do get it right then the spring to operate the brake light isn't getting enough movement to operate the switch - running with no rear brake light is tempting bit never a good idea. The brake light switch works when operated manually.
My thought process is :-
a) torque arm is in a fixed predetermined location due to it's fixings and is to all intents not the problem
b) footrest ditto
c) brake rod arm must be in right place due to location in hub with pads. maybe)

So the problem must lie with 1) pedal in wrong place, or 2) spring around end of brake rod to frame location is wrong or 3) the spring is u/s albeit it's pretty robust  or I'm an idiot!
(when I say spring I mean the top one on the brake rod arm that curls around the frame at the top end , not the spring on the adjuster for the brake rod.
Any advice would be welcome I've been at it off and on for 2 weeks and it's driving me mad!


Title: Re: rear brake puzzle
Post by: Bryanj on February 17, 2021, 11:17:37 PM
Move the arm on the brake plate a spline
Title: Re: rear brake puzzle
Post by: taysidedragon on February 18, 2021, 12:38:28 AM
The brake switch body has an adjustable thread on it to get the spring tension right.
If that doesn't help, you can take the spring off and elongate it a bit before refitting.

Have you tried adjusting the screw on the footrest bar to raise or lower the brake pedal. Might help?
Title: Re: rear brake puzzle
Post by: billdn on February 18, 2021, 05:29:10 PM
Move the arm on the brake plate a spline

Bryan you're amazing worked like a dream, just one spline and all fell into place! Have a virtual pint on me!
Title: Re: rear brake puzzle
Post by: billdn on February 18, 2021, 05:31:31 PM
Like the brake pedal and the actuating arm has a dot alignment system so does the rear brake arm and it's spindle. Have you checked these are aligned as well? If all the dots line up front and back it should work as Honda intended, if it doesn't then something is wrong. Either shoes are incorrect or brake rod is off another bike and shorter etc

Oddjob - it had better be the same brake rod as it's the one that come off, unless those pesky workshop gremlins been messing around again. Thanks for the confirmation but as you can see now sorted.
Title: Re: rear brake puzzle
Post by: Bryanj on February 18, 2021, 08:13:29 PM
As Oddjob knows it used to be a common workshop "fix" to move the arm a spline when no adjustment left but still material on shoes you just had to remember to move it back when new shoes were fitted! Have you fitted new?
Title: Re: rear brake puzzle
Post by: Bryanj on February 18, 2021, 09:12:52 PM
Yes Ken, even remember filing a spline out of the arm so it could be moved two, only on mine of course never a customers!
Title: Re: rear brake puzzle
Post by: billdn on February 20, 2021, 06:25:28 PM
So when you moved the arm on the splines did the punch marks line up? I suspected it was the spline alignment but as I said IF when they line up it still wouldn't work there was something wrong like wrong brake rod.

Oddjob - there is a mark on the spline shaft but not one on the brake arm , maybe a replacement arm from PO but not the first time I've removed it and was ok previously, just one of those small things, think I'll punch on a mark for next time!
Title: Re: rear brake puzzle
Post by: billdn on February 20, 2021, 06:26:48 PM
As Oddjob knows it used to be a common workshop "fix" to move the arm a spline when no adjustment left but still material on shoes you just had to remember to move it back when new shoes were fitted! Have you fitted new?

Yes bryan , new shoes fitted and by looking at old ones , glad I did!
Title: Re: rear brake puzzle
Post by: Bryanj on February 20, 2021, 08:28:55 PM
If yhey were that bad i bet the arm had been moved to compensate
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