Topic: Rear break broke...

[waldezy]

So...this happened today. After riding home from work, I'm starting to slow down for a left turn and use both breaks as I normally do. But this time something is different. When I pressed the rear break pedal it rejected my input violently then "POP" - then the pedal was extremely firm and didn't work. When I got home, I look at it and this is what I see....no more linkage. What on earth could have happened?!

[waldezy]

Another view...

[CycleRanger]

Where is the rear brake stopper arm?  Looks like the bolt fell out where it attaches to the brake plate.

[540nova]

Agree, your bolt came out, and the outer plate rotated. BTW, where's your axle nut cotter pin?


1974 CB450, 2006 CBR1000RR

[waldezy]

I took it off as I was going to start taking the wheel off - then decided to leave everything and take a pic first and throw it up on here.

[waldezy]

The arm is there - just need to look hard. It's all painted black.

[BomberMann650]

Yeah looks like that brake arm bolt sheared off with a bit of vengeance

[waldezy]

Dang - just when I thought I was "done" with the build. I've almost stopped the oil leaks - almost - and then this! I guess no one is ever truly done aren't they?! Thanks for the help!

[waldezy]

Tell me about it. That is so crazy - I wonder what caused it to shear? Perhaps it vibrated loose or something. It was a bad day for the bike today. During the ride I found my pegs were coming loose as well.

[754]

Its a special shouldered bolt.. Do you know what was in there? Not the place for a hardware store cheapo bolt..
 You need the proper bolt for brake arm
 The brake rod, the brake actuating arm
 Maybe the bushing pivot the rod goes thru..

[bryanj]

Or there was no cotter pin and the nut came off

[jas67]

I had that happen on a CB360 a few years back.    I definitely made sure to get the correct castle nut and cotter pin to make sure it didn't happen again (on that bike, there was a stud in the arm of the backing plate).

It is likely that it just had a regular nut on it when it happened.   

[USMC5811]

I can empathize.
Lost rear bolt on torque bar, drum rotated, actuator cam sheared off about 6 miles from home at dusk.
I almost expected it to start raining.


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[70CB750]

Lucky indeed.

[flybox1]

Or there was no cotter pin and the nut came off

+1

[nobody]

If this or something similar to this ever happens again, I would recommend pulling over to assess the damage rather than riding all the way home first... broken parts on a two wheeled machine, always a safety risk.

[Bodi]

Not uncommon. The torque arm comes loose, you touch the pedal and BAM! The geometry works so that the brake plate turning tightens the brake, meaning more force to rotate the plate, meaning tighter brake... extremely dangerous on wet pavement or dirt/gravel where the tire will skid before something breaks to release the brake.
The torque arm attachment points are part of my pre-ride check: fasteners secure and cotter pins in place. Do not substitute in standard bolts if you don't have the special parts.