CX v-brake problems: what happened here?

[L'arriviste]

Second time this happened and as a mechanically inept individual riding my first ever CX bike and someone who runs to the LBS at the first sign of trouble, I want to understand what happened and why.

The bike is in the shop getting new (and different) brakes but in the meantime here's what the 'offending' 4ZA mini v-brake looked like before I took it there:

You can see clearly a lot of play and all the silver bits of the caliper were totally loose. The spring had also gone floppy. It's not like the play could be tightened out anywhere - none of the screws or bolts appear to act on that. Meanwhile the whole brake obviously fails to function correctly with one caliper slack.

I didn't screw around with the bike before this. I rode it in moderate offroad conditions, no impacts or crashes (at least not in that area, anyway ), washed it and replaced the wheels and popped the noodle back in only to discover that the brake didn't work properly. Was it something I did? Could it be fixed easily?

 

[Bustedknuckle]

Second time this happened and as a mechanically inept individual riding my first ever CX bike and someone who runs to the LBS at the first sign of trouble, I want to understand what happened and why.

The bike is in the shop getting new (and different) brakes but in the meantime here's what the 'offending' 4ZA mini v-brake looked like before I took it there:

You can see clearly a lot of play and all the silver bits of the caliper were totally loose. The spring had also gone floppy. It's not like the play could be tightened out anywhere - none of the screws or bolts appear to act on that. Meanwhile the whole brake obviously fails to function correctly with one caliper slack.

I didn't screw around with the bike before this. I rode it in moderate offroad conditions, no impacts or crashes (at least not in that area, anyway ), washed it and replaced the wheels and popped the noodle back in only to discover that the brake didn't work properly. Was it something I did? Could it be fixed easily?

I think the screw in post, the thing that goes into the fork, may have come loose, unscrewed. But tough to tell w/o seeing it.

 

[alitogata]

It looks to me as like the brake wasn't installed properly in the first place (the screws weren't screwed straight) so got damaged completely while you rode the bike. Well done of changing it.. It's not wise to ride with damaged brakes.

 

[L'arriviste]

It looks to me as like the brake wasn't installed properly in the first place (the screws weren't screwed straight) so got damaged completely while you rode the bike. Well done of changing it.. It's not wise to ride with damaged brakes.

I think the screw in post, the thing that goes into the fork, may have come loose, unscrewed. But tough to tell w/o seeing it.

Thanks! It was all tight though. Nothing loose there, just the brake caliper itself.

 

[MarkvW]

Is it possible that there are one of those convex washers in there, and things got rotated out of proper alignment?

 

[purcell]

If the boss was tight, and the mounting bolt was tight then the boss is too long as the mounting bolt was bottoming out.

The easiest way to solve it is to just get shorter bolts mounting bolts and put a spacer on the boss so that when the bolt tightens down, it tightens the caliber into place.

 

[Bustedknuckle]

If the boss was tight, and the mounting bolt was tight then the boss is too long as the mounting bolt was bottoming out.

The easiest way to solve it is to just get shorter bolts mounting bolts and put a spacer on the boss so that when the bolt tightens down, it tightens the caliber into place.

Yep, or shorten the boss..

 

[L'arriviste]

I should update this, now winter's coming on:

The LBS fitted TRP EuroX cantis instead. No problems since then.

 

[ustabe]

It looks wrong but almost every one of these brakes is different so it's hard to tell what it's supposed to look like. Post a photo of the other caliper, please. It might help.

 

[L'arriviste]

It looks wrong but almost every one of these brakes is different so it's hard to tell what it's supposed to look like. Post a photo of the other caliper, please. It might help.

Hey, sorry, as I mentioned just above, in the time since I posted the query I no longer have those brakes now.

It happened twice and I'd had enough, so I had cantis put on and they've been excellent ever since.