Re: RE: Re: DeRosa Merak Rear Brake Problem

On 1/1/2025 6:20 PM, cyclintom wrote:

On Wed Jan 1 16:14:05 2025 AMuzi  wrote:

On 1/1/2025 2:46 PM, cyclintom wrote:

I discovered why I got the Merak for nearly nothing.
>
When it came time to install the rear brake I found a bolt somehow installed in the rear B-stay brake hole that has a 5 mm threaded hole in it. It is aluminum so the forward end of the device (between the B-stay and seat tube) which appears to be a normal brake lock, is stripped.
>
Since the B-stay is carbon fiber I don't think that it is screwed in. I would think that it is a slight interference fit which would explain the stripped allen end. I suppose I could thread in the 5 mm allen bolt and using a puller, push the fitting out. Hopefully that would leave the original brake hole in original condition.
>
I have never seen a rear brake attachment of this sort so I am asking if anyone has ever seen anything like this and if they have any comments on it and if they could suggest a removal technique that would leave the hole in original condition?

>
There is something inside your rear brake mount?
And that is a bolt? Or a sleeve with a 5mm threaded bore?
What is a B stay?
What is a normal brake lock?
>
Could it be a stuck/corroded brake mounting nut? That would
be M6 not M5.  An aluminum nut may well be corroded in
place. Clean as well as possible, examine in a good light
with a magnifier if needed to see what it is an dhow it's
held in place.

 1. https://www.ebay.com/itm/387414175414?_skw=B-stay&itmmeta=01JGJ1SMVC3X64P451Y7V26RDP&hash=item5a33af2eb6:g:ojsAAOSwapJm8SeY&itmprp=enc%3AAQAJAAAA4HoV3kP08IDx%2BKZ9MfhVJKkKk%2BT%2BCfPB1NFw1gIOhTDcX5INzW7ZyWXx6ymLMxxUkrjgqEbMjg7byxSVBbnUf1OSX%2Fvcil1p15XMnhKWGWTb3w6SI%2BSogBVxH8U3lJYJ9cCu1IHbjcweuReuInwNEbjWdSN0YS743SYts0ZqnTbaXTlvuKSY6sywZQureWu4x4wfDXgFkt0cutCbAuWgNrXUrAyZ0kHi9fGa9FDktoHBJ2Ou5RhYYeJpFZojnp7qCmg2u61ElYwc8ZHbrzANgaQ2bBquUYm9q0wd1ExtoN%2Bp%7Ctkp%3ABk9SR-bN5sGEZQ
 2.  https://www.ebay.com/itm/183751311056?_skw=Ultegra+rim++brake+fixing+nut&itmmeta=01JGJ1RGGSH2W5TD4WMQXC1WN8&hash=item2ac86e7ed0:g:SLAAAOSw5cNYbIi8&itmprp=enc%3AAQAJAAABAHoV3kP08IDx%2BKZ9MfhVJKmDXGrXXDIzZaBH8%2FV8tvPcg9OmXd%2BLSGTrZ0E3ttBzz91TsnLw5frOpgp5%2BaLgKnsVuajVdLQlissnahvLQ1s%2B8jjBW5Zwe9gx3ufmUqMQbR28s5kmllEA6TneV3nRuIyCrBZ3w2AHL8T%2Fum15FGCrgWW3lJa5poIsouZTt3cjjMZUTQ6ChkB5U0JDjSSF6K8J4s9R1YtMY9twloP2CvPnXPEA01h2at9kiWlAko%2BecP%2FnrsuiewDvsK2lC1HohuyheFliyzVpmmF1v9KImGbXMTdMZt7gyFMor%2B%2BtTLFBurUsXqzG0OeVxPKt3VXc9zg%3D%7Ctkp%3ABk9SR7yI4sGEZQ
 3 No chance at all. The threads start at juust below the surface of the brake hole.

The answers to Andrew's questions are still not clear to me, except that a "B stay" seems to be a proprietary term for an odd frame configuration.
I don't recall seeing any brake mounting hardware that took an M5 fastener. I think M6 is normal.
The photos of the bike are helpful, but can you post and link to a closeup photo of the object(s) you're asking about? That, and/or a good engineering drawing of the relevant part might allow some of us to help.
--
- Frank Krygowski