Yet another stoopid question - how did my rear brake fettle itself?

[CrinklyLion]

I is confused.

On the way to work this morning I was approaching a cyclist-trap-gate so braked to slow down to negotiate the zig-zag.  There followed a most peculiar kershproingclunk noise, from the vicinity of the brake lever.  I hopped off, and had a quick look.  The rear disk brake on the Valencia was on, and it really wasn't going to release.  I could move the lever (a bit crunchily) but the cable wasn't budging (I could see the nipple not moving with the lever, if you see what I mean) and the brake wasn't coming off.   The cable outer had popped out of the twist-to-adjust thing that I don't know the name of.   (For those who haven't previously encountered my astonishing lack of grasp of the technicalities of bikes, I'll apologise now.  In my defence, I am trying!)

Fortunately for me I have a convenient friend who lives about 10 minutes walk from where I was.  She got an early wake-up call this morning, and 20 minutes ('cos carrying a backpack, a pannier and a bike with a rear wheel that won't turn does slow you down a bit) later I carried my bike into her garage - after she had also looked, agreed that it was a very stuck brake and that she, like me, has no clue at all about how disk brakes work and that 7:30am isn't the ideal time to start learning!  So off I tootled to catch a bus to get to work.

This evening, because she is a most excellently kind friend, she dropped my bike off.  Which has mysteriously fixed itself whilst sat in her garage all day.  Apparently she went to get it to put in the car and the back wheel was once again spinning freely.  She tested the rear brake, and it worked fine.  So she went for a spin round the block, and it behaved itself.

I can understand that it broke, if not what it was that was broken.  I fully expect that with my level of numptiness things break, and I don't know yet how to fix them.  This is normal and not the slightest bit confusing.

But can anyone tell me a way in which it can have fixed itself, or do we have to assume that she has fully park-tooled-up pixies in her garage?


(she quite liked my bike, by the way.  Although she said it was a bit like riding one of her kids' bikes, with her knees up around her ears)

[RichForrest]

How cold was it where you were this morning?
The brakes on my trike do that when the water inside the cables freezes.
Sat inside the slightly warmer garage they would have defrosted and sprung back into place.
The next step is to take the cable off and spray oil in or grease it before putting it back together again.


Rich.

[mrcharly-YHT]

Easily . . .

This happens when the cable isn't fitted correctly to start with (or the inner has slipped cause the bolt wasn't tight enough at the brake end). The cable outer isn't seated properly inside the cable stop on the lever, just caught on something part way. At some point it slips, things jamb (or brakes just stop working).

The lever gets knocked or wiggled, the cable outer catches on the thing it caught on before. Suddenly it seems as if it is all ok.

It isn't ok or safe, needs looking at. It's a new bike, drop it back to the shop.

[CrinklyLion]

Thank you.  I can (just about) understand both of those possibilities! 

I did wonder about ice, as it was pretty frosty but it wasn't arctic subzero - given that some people on here have been happily pootling about all winter I'd be a bit gutted if Valencia is too wussy to cope with a bit of frost. 

I'll get them to check it tomorrow, since it's already booked in, in case it's the 'something jammed' problem - it'd be bloody scary if the brake jammed on and wouldn't release in traffic, so I'd like to be sure one way or the other!

So we don't all need to move all our bikes into my mate's garage for magic pixie fixing then.  Shame.