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What brake is this?

Discussion in 'General Classic Motorcycle Discussion' started by texasSlick, Jan 1, 2020.

  1. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    I purchased this TLS brake plate from Dunstall back in the late 60's. It looks like a Triumph on the outside, but inside it is a different animal. Can anyone shed any light on this?

    TLS.JPG

    TLS_Inside.jpg


    For comparison, the Triumph inside is below:

    TLS_Inside_Triumph.jpg

    Note the Triumph plate has the cams wedging apart both shoes top and bottom. The Dunstall cams work on one shoe only, while the opposite shoe is on a pivot. The internal ribbing of the brake plate appears to be the same on both types. I am thinking Dunstall modified a Triumph brake plate, but what shoes did he use?

    The brake is a great TLS, with no tendency to self-augment. It was a drop in fit to the original Norton SLS.

    Slick
     
  2. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    Don't you mean Robinson modified one for Dunstall?
     
  3. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    This is what Dunstall had to say about them in two of his earlier catalogs, if that helps any. The first one is from his 1969 catalog, and the second from his 1966 catalog.

    Dunstal Drum Front Brake ca. 1969.JPG Dunstal Tickle Front Brake ca. 1966.JPG

    Ken
     
  4. kommando

    kommando

    Joined:
    May 7, 2005
    The plate used is the 68 only plate, the 68 had an odd cable route where the cable could get caught on the mudguard under compression and then pull the brake on as the forks extended. I suspect Dunstall got hold of the surplus stocks of the 68 plate cheap.

    On the cam the Triumph cam only acts on one shoe, the shoes are shorter than normal and the perch for one end is part of the brakeplate and does not move but the shoe can float, the cam is also shaped to only work on one shoe but did not need to be so.

    The Triumph shoes are wider than most others at the time, they only fit the Triumph hub with a flange on one side from 66 onwards. So if Dunstall was designing a brakeplate to fit narrower hubs then he needed to change to a different shoe or machine the Triumph shoes narrower.
     
  5. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    @kommando

    Thanks for the reply.

    Here is a pic of the triumph cam:

    TLSCam_Triumph.jpg

    It looks as if there is a ramp on both sides, but I can accept your explanation that one shoe floats".

    In any event, the Dunstall cam is very different, having a ramp on one side only as below:

    TLSCam2.jpg

    The cam actuates one shoe only, while the shoe opposite is on a pivot, and does not float.

    The shoes are my main concern. When it is time to renew the linings, I can send them to Vintage Brake. However, if the shoes should become lost or otherwise unusable, my TLS brake is a paper weight.

    Your input is appreciated. Thanks.

    Slick
     
  6. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    See if you can get hold of a 68 shoes from stock at Triumph dealer first. If not then there is the possibility of converting your brake to the later version, just by swapping parts?
     
    Last edited: Jan 2, 2020
  7. kommando

    kommando

    Joined:
    May 7, 2005
    The 68 Triumph TLS shoes are the same as the 69/70 TLS shoes, only the external lever changed and the fixing point for the cable outer moved up next to the fork lower so no help there.

    Here is the TLS brake plate showing the static perch for the non cammed trailing end of the shoe and the hole for the cam.

    [​IMG]

    Here is the cam, showing it only works on one side, even though because of the perch there is no shoe resting on the non cammed side.

    [​IMG]

    Here is the brakeplate with shoe fitted but no cam.

    [​IMG]

    and here are some Norton shoes for an 8" brake I bought incorrectly years ago, they may fit but the alloy shoe is not as substantial as the ones in your pics. You can have them for postage only, they are so old they may be asbestos linings though.

    [​IMG]
     
  8. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    kommando:

    Thanks for the reply.

    1) My brake plate does not have the static perch. The boss on mine, where the perch is on yours, is milled flat. The milled surface is approx. 0.875 inch above the turned ring (about 9.25 inch OD) surface. The height of the boss surface appears to be higher on mine, than on yours.

    2) My boss has two holes in it; one for the cam, and the other for a hard dowel that acts as a pivot. That second hole is visible in my first picture above. It is the black dot just above the rightmost cam lever. The corresponding hole for the other brake shoe is hidden by the mudguard stay.

    3) I have tried 8 inch Norton shoes. The dimension from the center line of the pivot hole, to the center line of action on the cam face is about 0.375 inch short on the Norton shoes. I appreciate your offer, however.

    From what I see on my plate, it is hard to imagine how Dunstall could have taken the 68 plate, and milled the perch off and ended up with what I have. Here is a blowup of the boss... hopefully you can see what I have described regarding the boss.

    TLS_Boss.jpg

    Thanks again, I can tell you went to some trouble to help me.

    Slick
     
  9. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    The corresponding hole for the other brake shoe is hidden by the mudguard
    From what I see on my plate, it is hard to imagine how Dunstall could have taken the 68 plate, and milled the perch off and ended up

    Slick[/QUOTE]
    If you are talking about Dunstall, you are also talking about his engineer John Robinson those two together could come up with almost anything except reinventing the Atomic bomb!
     
  10. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    If the Norton TLS shoe can’t be made to fit, what about the Norton 8” SLS shoe?

    [​IMG]

    If you’re in the UK, I can post you a couple of old ones with worn out linings, if you haven’t already tried that type.
     
  11. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    Haha- I guess you must be in Texas, not UK!
     
  12. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    Triton:

    Thanks for the offer.

    If you would, please measure those shoes and report back on the dimension in red. The brake shoes I have are approx. (best I can measure without precision instruments) 6.375 inch. That dimension is from the center line of the hole to the center of the actuator face.

    TLS_Shoes_1.jpg

    Slick
     
  13. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    Dead on 6”, by eye and a hand-held rule.

    That’s no good, is it!

    1/2” pivot hole.
     
  14. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    Looks like a strongly made shoe. Could they be pukka racing parts, such as Manx or AJS 7R?
     
  15. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
  16. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    Yes, it looks like the shoes might have been replaced.
     
  17. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    Looks like the same brake on Mystery Brake plate Aug 22 2009 on this website - scroll down to the absolute bottom of this page.
     
  18. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    I get 6" for the Norton 8 inch SLS. I tried Norton TLS ... did not fit, do not have them anymore so cannot measure.
    Yes, I must say whoever did Dunstall's machine work was a bit crude, as evidenced in the cam lever arms. The shoes have rough casting marks but the machining is acceptable, considering the part is used unseen.

    I am not familiar with these, but will do some research. Thanks.

    Replaced? These are as purchased new from Dunstall circa 1967 or '68.

    Thanks for the help, guys.

    Slick
     
  19. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    That brake plate looks very similar to mine! The 185 mm dimension given in the sketch (across the wide part of the shoe) is similar to what I measure on mine ..... 187 +/- mm. He gives a shoe width of 33 mm, I measure 1.25 inches or 31.75 mm for my shoe width.

    The mystery remains unsolved.

    Slick
     
  20. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    Any castings name & letters/ numbers on brake plate? I think is a Triumph and they come with 3 different types of cable pull.
     

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