Author Topic: c10 front brakes  (Read 1105 times)

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Online camman3

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Re: c10 front brakes
« Reply #15 on: September 29, 2020, 08:55:25 pm »
As far as I can see, nobody has mentioned the importance of centralising the fulcrum pivot point, by slackening lock nut, applying brake and re tightening nut :-\
https://bsac10c11c12.co.uk/smf/brakes-wheels-service-sheets/front-hub-brake-(7-inch)/
Graham
1957 C12
In sunny (sometimes) Christchurch, Dorset, UK

Offline ThomasC11

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Re: c10 front brakes
« Reply #16 on: September 29, 2020, 09:05:09 pm »
Puuh, maybe I am the only one who is not too happy with the old BSA workshop manuals but at least I do not understand what the fulcrum pivot point is nor do I see a lock nut in the drawing. Dementia or bad description...  :-[
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai

Online camman3

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Re: c10 front brakes
« Reply #17 on: September 29, 2020, 09:25:56 pm »
Third paragraph on first service sheet in that link, states the importance when fitting new linings
The section of the nut can be seen in drawing on same sheet.
1957 C12
In sunny (sometimes) Christchurch, Dorset, UK

Offline steve70

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Re: c10 front brakes
« Reply #18 on: September 29, 2020, 11:39:54 pm »
Ive seen and done that

Online Ginge

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Re: c10 front brakes
« Reply #19 on: September 30, 2020, 02:35:02 am »
You’ll be right Steve. Wellington doesn’t have hills does it?

My pivot points were wrapped in brass shim stock by the previous owner to take up wear.  I removed them and ended up with worse brakes.  That “grab,catch and flex” self servo effect is the answer. You just need to gauge the pivots out. 

Shim stock probably isn’t the best answer though.  Oversize linings from a brake specialist might be.

Cables do make a difference. Cheap pattern cables are not worth the effort.
Ginge.

Offline steve70

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Re: c10 front brakes
« Reply #20 on: September 30, 2020, 06:48:02 am »
Ginge
Im in the Wairarapa, but my drive is 100 metres all down hill, so its a good test , Ive got another set of linings on some shoes, not sure what model, but they are steel  amongst a whole lot of parts I bought some time ago, the grip is by hand a lot better than what I have by miles, I cant get that softer lining  material here,and there is only one place that does it and hes almost olde rthan the bike so im going to bond these onto existing shoes, probably have asbestos in them, but so have my lungs:)   

Offline ThomasC11

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Re: c10 front brakes
« Reply #21 on: September 30, 2020, 09:04:23 pm »
Quote
Most riders who come in with rubbish brakes have a gap between the shoe & drum you can measure in fractions of an inch
To work that gap  should be .050" tops .
Today I opened the front brake and checked the clearance. It's about four times this value. However, there is no possibility to adjust it...
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai

Online Owen

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Re: c10 front brakes
« Reply #22 on: September 30, 2020, 09:57:51 pm »
You could always adjust the cable/rod to take up the slack?
1940 C12 (350cc)
1945 C10 & C11
1953 C10 & C11

Offline chaterlea25

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Re: c10 front brakes
« Reply #23 on: October 01, 2020, 12:24:28 am »
Hi All,
Thomas the 050. measurement is inch measurement  =1.25mm
4 times that = 5mm    :o
What thickness are the linings on the shoes?  memory tells me new linings are about 4mm on the 5.5inch brake
and about 5mm on the 7inch front shoes

John

Offline ThomasC11

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Re: c10 front brakes
« Reply #24 on: October 01, 2020, 08:54:51 am »
Yes, about 5mm. I have not measured the thickness now. But they are relatively new. In my opinion gap and thickness are primarily not important because you adjust the cable/rod anyway. Of course I do that. But at some point the shoes start to scratch and you have to adjust them accordingly.

I'm wondering if Trevor's hint (.050" tops) is realistically applicable here and if you just have to pay attention to the right angle between rod and cable (after adjustment, of course).
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai

Offline chaterlea25

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Re: c10 front brakes
« Reply #25 on: October 01, 2020, 08:38:25 pm »
Hi Thomas,
I went and measured up a 5 1/2in. brake and brake drum today
The old linings are worn to approx 0.1in (2.5mm) new ones measure 0.155in (just less than 4mm)
The difference between the shoes and drum is approx 0.070in. (1,75mm)
It looks like if I fit the new linings I will have to turn them down to fir the drum?
( I did not have the springs fitted or parts cleaned which might make a difference?)

Also I noticed that the 5 1/2in brake does not have a movable shoe pivot as used on the 7 and 8in. brakes

If your brake shoes / drum have almost 5mm difference you have a problem ???
Are the steel pads fitted to the cam ends of the shoes ? this might account for some of the difference you measured

As an aside has anyone experimented with modifying to floating shoes with asymmetric linings as used on later BSA models ? (pic below)

John


Online ianinglis

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Re: c10 front brakes
« Reply #26 on: October 02, 2020, 06:02:07 am »
looking at that diagram you could flip the shoes over and fit them incorrectly or am i missing something???




ian
BSA C10L 1956 - JFO 588
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Online timsdad

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Re: c10 front brakes
« Reply #27 on: October 02, 2020, 07:22:39 am »
Shoes can often be fitted wrong by swapping then over but a lot of braking efficiency is lost if the leading edge is trailing instead of biting first.


My old bikes have usually been quite worn up when I've bought them so, if the brakes are not fit for purpose, I can get them working well enough by just replacement or repair of worn parts, proper assembly and bedding them in well. I use my old bikes because I love them for their faults and foibles and to transport me back to my younger days as well as my destination.

I have newer bikes equipped with Brembo, Tokiko and Nissin discs to stop me on a sixpence so my BSAs just need a bit more forward planning and a much harder squeeze. If you want really good brakes, just get yourself a Hinckley Triumph for everyday use. You'll never get a puny tin drum to do a stoppy.


Ray
Just a motorcyclist.

Online Tman

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Re: c10 front brakes
« Reply #28 on: October 02, 2020, 08:31:23 am »
looking at that diagram you could flip the shoes over and fit them incorrectly or am i missing something???
ian

People always could, did and probably still do, then they promptly go on Net forums and complain about how they couldn't get their awful brakes to work on their old "Brit" etc etc.
Much-maligned, just like that other butt of the ignorant, Joe Lucas. ;)

Offline ThomasC11

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Re: c10 front brakes
« Reply #29 on: October 02, 2020, 05:14:38 pm »
Thank you, John!

Quote
If your brake shoes / drum have almost 5mm difference you have a problem

Hm! My outer brake shoe diameter is 136.8mm whereas the inner drum has 139.7. So about 3mm difference. There is a slight burr on the drum edge. The linings have about 3mm thickness. What now?  :-\

Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai