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Bultaco Re Liner


millerme
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Have a Nice day

Larry

;PS I wish someone would show & tell about brake lining truing, it must be simple tooling, if I should figure it out I will share with

all interested.

Larry, my thoughts initially were to bore out the remains of most of the existing steel liner and make a new new one to suit. I would have made a simple mandrel and mounted the bare hub on this, with just the bearings in it (no rim). I feel that the hub is pretty substantial and won't be pulled out of round by the spokes. (I've built several wheels for people and never had that happen). So a pretty simple set up really.

The thing that troubled me most was deciding what fit I was going to choose. It had to be an interference fit but the precise class of fit I couldn't decide upon because I didn't have the experience of just how much the hub might expand if given a good amount of heat, and what I could get away with, if you know what I mean. The last thing I wanted was for the liner to spin inside the hub when I applied the brake.

So I just took the lip off the edge of the old liner and went with thicker material on the shoes. When I was doing this on the lathe the hub was spinning really true inside, so I don't think you need to necessarily keep it in the rim for accuracy.

Posted a couple of pictures of my setup on this link

http://www.ralphsbultaco.blogspot.co.uk

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Ralph, very good, really just what I needed to shove my old head in the proper direction keep it simple is always the best.

The main thought about the wheel being mounted is the cost of lacing, because I usually am capable of breaking spokes

in a retrue mode, they tend to grow together in time, even using torch judiciously, still tough & wouldn't care to try unlacing

let alone getting the offset right, but those who do such would not worry about my fears.

Thank you for pictures and good luck with your build.

Larry

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About your brake re-lining and turning down the friction material on your brake shoes.
For maximum braking power, the entire surface of the lining of the brake shoes should make contact with the brake drum.
To achieve this, you should put shims between the cam and the brake shoes before pulling them tight against the cam, as if you would be applying your brake a little bit.
Then you should turn down the lining to the exact diameter of the brake drum.
I hope my English is a bit comprehensible :unsure:

Skim like this...

post-10952-0-47976000-1427564680_thumb.jpg

note: the 3 in 1 oil in the picture is not desirable on the shoes!!!

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Yes indeed Larry, very easy for the spokes to snap when trying to loosen the nipples. But you'll know yourself, lathes with enough swing to accommodate the full wheel aren't as common, so most will find themselves forced into taking it apart for that reason. - A thought just came into my head, I know where there's a railway restoration yard - their bound to have big machinery - that's me sorted out next time.

I kinda mentioned the hub distortion thing just because I'd heard it discussed here in another post somewhere and it was in my head while I was writing.

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Thanks for the response.

Smelling how did you hold the shoes tight against the cam?

A thought I had along this line was a small turnbuckle, there I go over thinking again, Ralphs zip tie & wire worked for him,

haven't tried it but we know it works.

By the way I rode a 199 today that had the best RH cable brake ever!!

It had a heavy inner & outer cable, but I think the stock old shoes made a large difference, wish I knew if that lining can be

duplicated, I suppose I could take my 199 shoes as they are still OEM.

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One thing to remember when skimming brake shoes if they are new old stock or you are unsure of the lining materials make sure they are not asbestos!

New lining should be fine as asbestos has been banned for quite a few years

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Ralph, the way I machined a full wheel in 1978 was indeed @ our local rail yard on the lathe they machined wheels

on, it was big & awkward but easy enough to chuck the comp wheel, bore, press liner, bore to size, get home 4 hours

later (made the liner earlier) never did another after this

Larry.

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If you have a decent sized milling machine you should be able to the clean up the braking surface with the wheel assembled using the sprocket to mount off, I've done the same to a damaged bearing housing

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Thanks for the response.

Smelling how did you hold the shoes tight against the cam?

A thought I had along this line was a small turnbuckle, there I go over thinking again, Ralphs zip tie & wire worked for him,

haven't tried it but we know it works.

By the way I rode a 199 today that had the best RH cable brake ever!!

It had a heavy inner & outer cable, but I think the stock old shoes made a large difference, wish I knew if that lining can be

duplicated, I suppose I could take my 199 shoes as they are still OEM.

Just used the standard spring and some lockwire. Very small cuts (0.05 - 0.1mm with a sharp tool.

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