front brake pivot

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RTichard Woolnough
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front brake pivot

Postby RTichard Woolnough » Fri Dec 01, 2017 12:07 pm

attempting to get the front brake to do just this other than carrying it for the ballast effect, I'm wondering if a slightly larger circumference on the pivot would assist, I have measured the pivot and could turn another up slightly larger 1/16" or perhaps a little more, this would have the effect of pushing the trailing ends of the shoes towards the drum a tad, my view being that a little more of the lining face would come in contact on application, whadda you think? kind regards

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paul.jameson
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Re: front brake pivot

Postby paul.jameson » Fri Dec 01, 2017 9:16 pm

Rather than your suggested approach, I would mount the brake plate and shoes in a lathe and turn them to match the internal diameter of your hub. You will probably need to operate the brake partially to achieve this diameter which you can do,very carefully with suitable adjustment of a piece of wire operating the brake arm and secured round something like the brake anchor stud. As trial and error is needed, use a soft wire rather than anything stiff.

Having got the diameter of the shoes correct, fit them to the wheel but before you tighten up the nut which locks the brake plate to the spindle, put the brake on fully. This centralises the shoes on the hub. Tighten up the brake plate nut, then the spindle nuts and go and try the brake out. Just be careful using it for the first time. It may work an awful lot better then you expect.
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nevhunter
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Re: front brake pivot

Postby nevhunter » Fri Dec 01, 2017 10:10 pm

I've had some pretty ordinary front brakes on bikes with, steel drums firstly. Wrong linings (too hard) and dirty shoes (oil and grease contaminated.
The leading shoe does most of the retarding as it self servo's, so it wears the quickest, THEN the unworn trailing shoe takes most of the effort you put on the cable trying to make it work, (push) against the rotation of the drum.. SO either use a much softer trailing shoe or reduce the area in contact with the drum so that shoes pressure is increased to (1) make it more effective in the "normal" direction of rotation and (2) increase the rate of wear so it stays more even with the leading shoe.
Dirty glazed linings won't work well so you might get some temporary improve with roughing up the surface a bit. Years ago people who did relining had more choice of lining materials. The one for the trailing shoe as shorter and softer material. IF your drums were oversize thicker linings or a packer (if riveted) was used underneath the lining to get more area of contact. With Bonded linings they usually are ground to the drum diameter to some extent, but as explained some out of centre is possible. Many backing plates are buckled also so the plate runs tilted and the anchor pin is often bent at an angle as well as the piece the actuating cam runs in being bent out of true also. If it's worn the same effect happens. If you attend to all the above your front brake WILL work quite well though it will not be as good as the grooved disc brakes on later bikes, ever. CAST iron brake drums are far better than steel for braking action. If you have steel ones and are not happy you might have to experiment and be very selective in getting the right lining material. Your drums should run true and spoking the wheel can pull them out of true if the wheel rim is damaged and the spokes are very uneven in tension. Nev

RTichard Woolnough
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Re: front brake pivot

Postby RTichard Woolnough » Sat Dec 02, 2017 1:56 pm

I'll have a go in the lathe provided I can mount them! see how they perform, the shoes were 'stuck on' by Breens last year so have minimal mileage on them, although I did try to bed them in down the Killarney mountains in August, as I mentioned in another posting I do have what appears to be an original Ferodo type which if push comes to shove I can replace these with. Kind regards

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Re: front brake pivot

Postby paul.jameson » Sun Dec 03, 2017 8:06 pm

If your brake shoes are alloy and the linings are glued on rather than riveted on you have a very good chance of them falling off in due course, which can be embarrassing, to say the least. If the shoes are steel, you may be ok with bonded linings. For some reason, Ariel alloys and brake lining bonding materials don't seem to like each other. Strangely enough, the different alloys used in Grimeca brakes on the Healey don't seem to have the same problem.
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RTichard Woolnough
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Re: front brake pivot

Postby RTichard Woolnough » Mon Dec 04, 2017 8:24 am

yes they are steel shoes which rather surprised me when I first removed 'em, 'tis just a case of finding a large enough vernier to measure the drum now I guess. kind regards

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Re: front brake pivot

Postby RTichard Woolnough » Thu Dec 07, 2017 11:41 am

O.K ready to go but stumped at first hurdle, how do I dismantle the speedo drive to get the inner sprocket off pse? kind regards

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simon.holyfield
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Re: front brake pivot

Postby simon.holyfield » Thu Dec 07, 2017 12:12 pm

There's a split pin in the hub of the gear. You might need to slacken the lock nuts and wind the speedo drive in toward the centre of the wheel to see it.

Some pictures here:

http://ariel-square-four.blogspot.co.uk ... meter.html
cheers

Simes

'51 Square Four, Masquerading D3 Bantam, '58 Huntmaster, '42 W/NG, http://ariel-square-four.blogspot.com

RTichard Woolnough
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Re: front brake pivot

Postby RTichard Woolnough » Thu Dec 07, 2017 5:45 pm

thanks Simon, after my posting I googled the request again an eventually found an exploded diagram of one on a Norton, I think it was, lo and behold , 'tis owf! thanks and kind regards


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