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metisse

Re Lining Brake Hubs

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For a French chum, could anybody please tell me if there is any particular material you need to use when re linging  Bultaco brake hubs where the chrome has worn .

 

Thanks

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The "best" option is 316L stainless steel. I would have thought (because of safety implications) whoever is doing this work would know what they are doing without having to ask on the internet.

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For a French chum, could anybody please tell me if there is any particular material you need to use when re linging  Bultaco brake hubs where the chrome has worn .

 

Thanks

Cast iron, I had some done years ago by InMotion for a pursang.

 

I have also done some myself, but Its hard to get the cast at a reasonable price

Edited by suzuki250
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I too was shocked at the price of cast iron - I was quoted over £100 for a bit smaller than a brake drum a while ago.

 

Cast iron or mild steel will do but the have the disadvantage they will rust and their thermal expansion rate is not as close to aluminium as is stainless steel such as 316L.

 

If you are lucky you may be able to find an offcut of thick walled pipe. http://www.engineeringtoolbox.com/nominal-wall-thickness-pipe-d_1337.html

 

If you can't find the exact diameter you need you may be able to get some solid bar from a flange maker. Or you can get a bit that oversize , cut a bit out to reduce the diameter and weld it.

 

We used to use http://www.alexandercomley.com/ 

Edited by dadof2

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There is a firm who do metal spraying and have done many Bultaco hubs. Ask Tim Brittan at Classic Dirt Bike magazine ( on Facebook or google ) as he did a feature on them and uses them himself.

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Thanks for the replies, the guy asking works for an engineering firm, and just wanted me to pose the question. He has access to all the toys to do the work he just wanted to check with people in the trials know... what was best. 

 

I will pass this on

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I too was shocked at the price of cast iron - I was quoted over £100 for a bit smaller than a brake drum a while ago.

 

Yes, it ridiculous. I was fortunate to find a load of cast billets at a local scrap yard

The only down side to this is I don’t know the grade, but I’ve made a few nice vee blocks with it :)   

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Westwood Cylinder Liners uk do a liner, WCL41BFL , Bore 124, Dia 129.96, length 259.16, about £85 all in. I have machined my hubs 127mm rear, 128mm front , going to give this liner a try, will update if successful.

DSCN4112.JPG

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                                                                  Salut

           Pour trouver du tube de fonte,tu pourrais deja chercher dans les documentation techniques de poids lourds un alesage de moteur voisin du diametre qu'il te faut et recuperer une vieille chemise du moteur considere qui te servira d'ebauche pour faire

       la frette fonte a mettre dans le tambour Bultaco.A l'ebauche de la frette il serait peut etre bien de percer 6 trous sur cette frette qui ,une fois enfilee dans le tambour {a l'azote liquide ça serait bien,ça evite les deformations de l'emmanchement a la presse}

       Quand c'est emmanche,avec un TIG,il faudrait reboucher a la soudure alu les trous de la fonte ,soudure qui s'ancrera dans l'aluminium du moyeu et qui fera un"clavetage de la frette fonte ".Ce "clavetage "eviterait a la frette de tourner dans l'aluminium du moyeu

       quand le frein chauffera dans une grande descente sur la route.Ensuite,aleser la piste de freinage au diametre d'origine et les garnitures au diametre du tambour.

           Pour le freinage,Bultaco avait fait une belle conn...e   en mettant du chrome dur dans ses tambours car ,c'etait peut etre economique a la fabrication ,mais de la me....e a l'utilisation.Le chrome dur est connu pour sa resistance au frottement,ça glisse,on en

       met meme sur les tiges de verins ou les tubes de fourche,c'est donc un signe.Il ne faut pas s'etonner que le freinage etait deficient.

                                                                     Claude

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Just a update on the hub re line, found this brake disc (NDB776), has 23mm ID and plenty of meat on the out side, would leave quite a thin insert, but think it would be ok. Quite a lot of machining, but half the price of the liner, only £35 a pair,so this might be a new option. Will update when I figure out which way I go with this.

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                                                                                            Salut

      C'est vrai,prendre un disque de frein comme base pour usiner la frette est une bonne idee car comme les chemises de moteur ,la fonte employee est coulee avec centifugeation ce qui permet de ne pas avoir de soufflures de coulee dans la matiere.

      J'avais cite des chemises de moteur car je suis un ancien mecanicien poids lours et a l'epoque on reconditionnait les moteurs ,mais on ne faisait pas d'echange standard,donc les vieilles chemises envahissaient les poubelles.

                                                                                 Claude

    

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In reply to Richard Sawatzki about a pair of NDB776 car brake discs, what car are they from?

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