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It was late when I tried installing some replacement brake pads, and for some reason the top of the replacement pads wouldn't fit properly into the channel that is supposed to guide the pads (lower picture). I didn't realize the pads were sitting too low after insertion due to an awkward angle and tiredness (and general incompetence). As result when I squeezed the brake lever the pin got squashed (first picture below).

Question

Does this damaged pin warrant replacement? If so can this part be replace or does the entire caliper need to be replaced?

I assume brake force is not transmitted through the pin, as it is soft material, but I am not a brake designer so I am not certain. Once I figured out the pads were not seating correctly, I knocked them in place with a rubber mallet and ran the brake. Braking doesn't seem to be affected.

Inner caliper with damaged pin.

Side Note

Here is the channel that the top of the brake pads are supposed to fit

Caliper channel where brake pads would not seat correctly.

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2 Answers 2

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I think the only purpose of the pin is to retain the pad. So if you can convince yourself that the damaged pin isn't preventing the pad from sitting cleanly agains the "piston" and that it is prevented from dropping out, then I would be inclined to think you're ok.

I've seen instructions for rebuilding BB-7 calipers, which makes me think that parts might be available – at least in some markets. The SRAM/Avid number for the "internals kit" is A150080A and they appear to be available, I found links to the kit at shops in the UK, in the US Amazon lists the item, but doesn't have stock. In any case a whole new brake assembly isn't too expensive (considering that you get a set of pads and a disk as part of the deal), so if you have any doubts I'd just go ahead and replace the caliper (or see if you can get parts).

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  • I was able to independently verify this answer with a certified mechanic, who said essentially the same thing, that as long as you can get the pad to sit flush on the static "piston" it should be fine. Braking force is transmitted to the pad via that channel at the top of the caliper and the caliper walls NOT the pin. I will also try and order the kit, just to be safe.
    – Rider_X
    Dec 16, 2015 at 18:14
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It looks that nothing else holds the pad on place except for this pin. So without this pin your pad should never sit well. I would say it even can fall down in some circumstances.
If I remember right, this part can be unscrewed all the way out, so you can try to find at least a second hand replacement of it.

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    The caliper walls and that channel ridge at the top transmit the braking force, not the pin. The damaged pin can affect how the pad sits, which could be a problem.
    – Rider_X
    Dec 16, 2015 at 18:15
  • @Rider_X That's exactly what i wrote. Thanks.
    – Alexander
    Dec 17, 2015 at 2:04

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