Author Topic: Front brake identification  (Read 1605 times)

Offline Rudgeman

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Front brake identification
« on: 14.10. 2019 14:17 »
Hi - I wonder if anyone can help me identify my '61 SR front brake ? On my first and only decent run I found the front brake worked half way decently but juddered badly. I've stripped it down expecting to find an oval drum - but found a runout of only 0.1mm - I wouldn'thave thought that sufficient to cause juddering on this scale.

So I turned my attention to the shoes. From the parts diagrams I expected to find floating shoes - but they're not. They are 8" diameter, 1 1/8" wide. The cam ends have steels shoes and the pivot ends are semicircular and fit directly to the pivot pin. I've attached a photo of them immediately after removal.

I read through a few really interesting posts on the topic of poor front brake performance - including the 8 pager - and there are many good tips. But first of all - what do I have here ? Is it an arrangement from an earlier, not floating A10 or is it some strange hybrid ?

The shoes have about 3mm meat left in them but one of them looks as though it's been contaminated with oil at some point, so I'm tempted to have them relined. Any suggestions on a reliable supplier for this service ?

Thanks in advance - R

Offline RDfella

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Re: Front brake identification
« Reply #1 on: 14.10. 2019 14:19 »
A picture would help, but .004" runout could be sufficient to cause your problem.
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.

Online JulianS

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Re: Front brake identification
« Reply #2 on: 14.10. 2019 17:22 »
The full width iron hub brakes did not use steel pads at the cam end, either they have been fitted due to wear or they are the wrong shoes. Can you see a part number on the shoes?

Offline Rudgeman

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Re: Front brake identification
« Reply #3 on: 14.10. 2019 19:05 »
Hi Julian,
                 Thanks for replying. They both have W1088&9 cast into them. They're identical as castings.
Kind regards,
                         R

Offline Swarfcut

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Re: Front brake identification
« Reply #4 on: 14.10. 2019 19:28 »
The ever helpful Draganfly list these shoes as 42-5867/8, and state that they are "handed." I seem to remember the linings are not located centrally over the end pivots, as the cam and pivot areas are  slightly offset laterally. So rather than being identical, the shoes  are more like mirror images, hence two part numbers rather than a pair of identical interchangeable shoes under the same number as for other brakes.
 
 Try a different orientation, but from Julian's observations a new set of shoes is probably the best way to go. The casting numbers may or may not be relevant, except to identify the source of manufacture rather than a BSA part Number.

Swarfy.

 

Online JulianS

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Re: Front brake identification
« Reply #5 on: 14.10. 2019 19:48 »
W numbers are Triumph parts and they are probably for the mid 1950s half width Triumph brake. I would scrap them.

For floating shoes the parts are 68 5524 leading and 68 5525 trailing.

Photo shoes A10 front with floating shoes.

Offline Rudgeman

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Re: Front brake identification
« Reply #6 on: 14.10. 2019 21:58 »
Ah - no wonder they don't look like any of the diagrams or parts I've been looking at !

I can't tell you how helpful and friendly it is to get such informed assistance so easily. Thanks !

Draganfly are out of stock of these shoes. I can find them on Feked but have no experience of them as a supplier. Can anyone recommend a supplier ?

Kind regards,
                         R

Offline RogerSB

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Re: Front brake identification
« Reply #7 on: 14.10. 2019 22:45 »
My G/Flash is 1960 and still has single leading edge shoes (see photo). I think BSA changed to floating shoes for 1961.

Also here's an explanation of how drum brakes work that I put together for my own reference some time ago - made it into a jpg and a pdf file to put on here in case it may be of interest (I think (hope) it's all correct - I'm sure someone will point it out if not *smile*

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Offline Greybeard

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Re: Front brake identification
« Reply #8 on: 14.10. 2019 23:00 »
Draganfly are out of stock of these shoes. I can find them on Feked but have no experience of them as a supplier. Can anyone recommend a supplier ?
I've not had any problems with Feked
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Offline Rudgeman

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Re: Front brake identification
« Reply #9 on: 14.10. 2019 23:28 »
I've done quite a search on line and only Feked and Hawkshead and some ebay people list 68 5524/5 shoes. I'm surprised so few suppliers list them.

Interestingly, Hawkshead refer to them as A65 62/3. I've gone back to the 1960/63 BSA parts list and it shows shoes that look non-floating like mine, but with no steel cam shoes. The part numbers are 42 5867/8 rather than 68 5524/5. Any idea why this parts list shows diagrams of non-floating shoes when the literature refers to floating ?

I'm not familiar with Hawkshead either, so I guess I'll just have to take a punt on one of them. Any experience on these suppliers you could share with me would be welcome.

I'm also still interested to know whether you think 0.1mm drum runout would cause this problem.

Kind regards,
                         R

Offline Billybream

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Re: Front brake identification
« Reply #10 on: 15.10. 2019 06:24 »
I used Feked for some full width hub 7" shoes, they were unfortunately approx 3/32 wider than original on actuator fulcrum, easily rectified, on the box they were listed suitable for a host of other applications, they were cheaper than a reline and perform ok on my Super Rocket rear.
I left feedback and got a personal response, I would recommend Feked as a supplier as order process and divery and packaging was first class.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline RoyC

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Re: Front brake identification
« Reply #11 on: 15.10. 2019 06:29 »
Draganfly are out of stock of these shoes. I can find them on Feked but have no experience of them as a supplier. Can anyone recommend a supplier ?
I've not had any problems with Feked

I have always had good service from Feked.
My bike is a 1958 A7SS
Staffordshire UK

Offline Tomcat

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Re: Front brake identification
« Reply #12 on: 15.10. 2019 08:10 »
I've bought plenty of parts from Feked and highly recommend them. Prompt service to Australia.  *smile*
59 Super Rocket 

Offline Swarfcut

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Re: Front brake identification
« Reply #13 on: 15.10. 2019 08:40 »
  To my eye, Roger's picture above shows the shoes with a distinct location for the fixed pivot. These are likely to be the 5867/8 earlier type. Julian's picture shows "floating" shoes with a flat pivot area, which is fitted with steel pad, shaped to allow a small amount of movement for the shoes to float and achieve better drum contact.
 As this is a possible improvement, providing the rest of the drum and backplate were unchanged, it would seem to me that the early and later shoes are interchangeable, and if so explains the short supply of earlier shoes. Bit out of my on hands experience here, so perhaps  folks more clued up on later brakes can add their thoughts. Do later floating shoes fit earlier full width cast iron hubs as a straight swap? The floating shoes appear to be identical, changing the pad from one end to the other converts the shoe to leading or trailing position, altering the lining positions in relation to the cam and pivot, rather than the two different shoes of the original design.

Swarfy.

Online JulianS

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Re: Front brake identification
« Reply #14 on: 15.10. 2019 09:17 »
The floating shoes were introduced on the Super Rocket for 1962 season - from September 1961 that is.

The shoes in my photo have the part numbers as earlier post.

The same shoes were used on the early A65 full width 8 inch brake until 1965.

BSA published a service sheet, number 85 in October 1961 which explains.

These floating shoes dont appear in the late A10 parts book, they appeared in the October 1961 supplement, parts service bulletin N3. Quite a lot of parts changes are in supplements such as this one.

I have attached both below for information.