Over thickness brake linings ?

Discussion in 'Other Nortons' started by Rohan, Feb 13, 2017.

  1. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    I have a set of brake shoes with new bonded linings.
    But the linings are too thick, they are a VERY tight fit into the drum.
    Don't know who did them, or when, or what grade the linings are, came with a project.

    What are my options for thinning them down - out with the linisher ?
    I'm thinking they probably contain asbestos...

    [​IMG]

    Makes a change from the usual worn out stuff......
     
    Tags:
  2. Burgs

    Burgs

    Joined:
    Dec 14, 2013
    Rohan
    if they were mine I would most likely shim the shoes out off the cams, 0.015 to 0.020" set them up in the lathe and machine to suit the drum size, this way you will get a good brake so long as the linings aren't too hard.

    For the dust I would just put my big arse industrial fan on and blow the dust out the door of my workshop, I would also use a dust mask.

    I ate more brake dust than I can remember before they told us it was no good for you (trucks, bikes , cars, and earthmoving plant), and come to think of it, we even ate a lot of it after they told us it was no good :shock: anyhow I am still here, also ate a lot of coal dust I reckon that was worst, you were still bringing black flem up on Sunday morning and it cleared out just before getting back into it the next week.

    Burgs.
     
  3. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Are they from RGM?

    There was a discussion a little while back about this. Apparently RGM ones are designed to rum without the steel shims between the shoes and cam.

    I didn't know this when I bought mine, so being in a hurry, I very crudely linished them to (approx) size!
     
  4. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Steel shims ??
    I thought that was only a bodge for worn out linings ?
    They are not in the parts book ?

    Burgs, interesting comments.
    If it bites, that stuff is not good, not sure I'd want to spread it about.

    Can I just grind off the ends of the brake shoes, and get back some clearance ?
    Or, use one new shoe with one worn one (!!). (Did I really say that ?).
     
  5. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    What Eddie is referring to are the shoe 'slippers'.

    https://andover-norton.co.uk/en/shop-de ... oe-slipper
     
  6. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Interesting.
    Do these 'slippers' appear anywhere before the Commando ?

    I don't believe that I've seen them in any Dominator parts lists,
    and certainly not in the Model 7 brakes.

    You do sometimes see well used (Norton) brake shoes with the ends somewhat worn away,
    so the need for these may well have existed well before they appeared ?

    There certainly isn't any room for them in these problem bonded linings.
    I wonder if the overall length of the shoes changed to accommodate them ?
    It would have to have ?
     
  7. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    I notice in the 850 parts lists that these slippers appear as item 17A,
    and the brake shoes are item 17.

    That almost sounds like they were an addition to the parts book, possibly recently.
    Do they appear in all 750 Commando lists (not having 750 lists to compare).
     
  8. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    This is where confusion can arise.
    If you look at the '73 parts list you should see the "Brake shoe c/w lining" part number has also changed from the previous 060828 to 063417.

    https://issuu.com/sealycycleservice/doc ... 72_06-3402
    https://issuu.com/sealycycleservice/doc ... 50_06-5034

    For '73, Norton in their infinite wisdom decided that the rear brake slipper and shoe which up until then had been supplied as one item (060828) should only be supplied as two separate items (slipper, 060013 & shoe without slipper 063417). :roll: (Info. from Norton Service Release, N3/34, Feb. '73).

    Unfortunately, shoes appear to be sold under either part number 063417 or 060828 so owners may inadvertently remove the slippers along with the old shoes without knowing slippers could still be required for the new shoes, or, attempt to fit slippers when they are already part of the shoe.

    Even AN appear to think 063417 is the same as 060828.

    https://andover-norton.co.uk/en/shop-de ... 43-a2-444-

    Further confusion arises from the front double-leading shoe brake where shoes and slippers were always listed separately for the Commando but some manufacturers/suppliers have taken it upon themselves to include the slipper as part of the shoe so it can end up with the same situation of shoes potentially fitted without slippers or owners attempting to fit slippers when they are not required.
     
  9. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    You can glue abrasive paper inside the drum and rub the individual shoes down against it, by hand.
    If you can find a way to mount the shoe on the backplate without the cam, and press it out against the emery paper on the drum and rotate it with the spindle in place, that's better.
    I use a white rubbery contact glue called Copydex, because it's easy to remove.

    And breathing the dust isn't clever.
     
  10. xbacksideslider

    xbacksideslider

    Joined:
    Aug 19, 2010
    Could they may have been set up for a drum that had been turned, and so, they present too large a diameter to your drum?

    Also, recall that, before disc brakes, there were some very aggressive linings that would tear up a drum. The look of those, to me at least, suggests that possibility.
     
  11. norton bob

    norton bob

    Joined:
    Nov 29, 2013
    High friction MZ GOLD linings.
     
  12. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Thanks for the replies folks, most helpful.

    Hmmm, these (MZ Gold) do look rather similar, don't they.
    http://www.rgmnorton.co.uk/buy/rgm-rear ... d_2471.htm
    [​IMG]
    Note there is no mention of these slippers here - so are they needed or not ?

    These shoes (of mine) came with a complete wheel, newly rebuilt I'd say, and the shoes had no show of fitting into the drum, so I don't think the drum was turned or to suit. Nor the shoes adjusted to fit, no sign the linings have been machined or adjusted at all since being bonded.

    LAB, is it possible the presence or absence of these slippers is the reason for the varied reports of Nortons drum braked braking capabilities ?? Seems like this slipper business has opened a can of worms ?

    I'm contemplating altering these brake shoes to take the slippers - to remove some wear effects off the cam end of the shoes, and also so adjust the fit of the shoes into the drum.
    The other approach might be to slim down the brake cam, but that might not be a good idea !
    They also seem rather tough...
     
  13. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    As I said, 063417 shoes were without slippers, however, as Eddie already stated; "Apparently RGM ones are designed to rum[run] without the steel shims between the shoes and cam." If what he really means is that 'slippers are not required' then RGM (and others) should say so in the description.




    I expect the lack of slippers (where they have been removed with the old brake shoes) has probably resulted in some owners believing their replacement shoe linings were undersized, but more than that, it's difficult to say.
     
  14. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Thanks LAB.
    A quick look at all the brake shoes advertised on fleabay - and without a close inspection it looked
    like not a single one has any mention of these steel slippers, and none shown with them.

    So, I suppose the question is do ALL the 3rd party shoes not use them. ?
    And, how to identify the OEM Norton ones that do use them ?
    The shoes in a spare 1973 (Commando) back brake are casting number 063278 - with steel slippers
    https://s32.postimg.org/582lqp7bp/Cdoba ... 50_Mk1.jpg

    I notice the shoes in a spare TLS Norton front brake here don't have the slippers - I wonder if they should have ?
    How do I find out ?? Perhaps a new thread is needed....
     
  15. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    I was a little surprised to find these shoes have the steel slippers - or at least steel end pieces.
    Certainly not removable, very tightly bonded/fitted there...

    [​IMG]
     
  16. Les P H

    Les P H

    Joined:
    Feb 18, 2012
    Just noticed this thread, but only days ago had the very same problem. First I bought some RGM MZ Gold 7" shoes for my M7. When it came to fitting them I noticed there wasn't a steel slipper fitted to the shoe ends. Got in touch with RGM expecting to have to buy the 0.875" steel slipper they sell but was told the shoes did not require them and were made to the correct size. I was surprised as I would expect the pressure pad ends would quickly wear but apparently not, or if they do they were sold as disposable so did not matter (apart from changing the cam working geometry a little). Anyway they fitted the front drum perfectly and with little usage the brake has become genuinely very powerful (note that I have implemented the mods on the cam and wheel spindles as highlighted by me some years back on the NOC Forum)
    Anyway I was so impressed I ordered a set for the rear 7" hub but this time they DID NOT fit being far too big to go anywhere near entering the drum. The linings are supposed to be asbestos free (glass fibre used instead) so I attempted to rub the shoes down with some 60 grade sandpaper. The lining sands down very quickly but it took many attempts to get the shoes to fit and eventually I reckon I had to remove 2mm off each shoe! Looking back I guess I could have filed down the pressure plate end but this is not too easy to get them flat and square. What was wrong then? Although I did not measure the diameter the front and back diameters of the drums, I am certain they are both identical diameters as the old shoes are identical and fit with the same clearances. This would then leave just one possibility and that is the finished size of the pressure pad on the the RGM MZ Gold shoes was far too big on the second sample. Not wanting to strip down the front brake again I can't prove this but comparing this second tight pair to the originals does indicate this being too big. Hope this helps others who are having the same problem...ATB....Les H
     
  17. no750

    no750

    Joined:
    Apr 7, 2016
    same problem here. Rear Break will not enter the drum because it is too big, olthough the radius of the break shoes look right. I milled both pressure plate ends about 1.5mm.
    Well, the shoes are now fitting into the drum, but now the retaining spring ist to long and has no pretension. I ordered a shorter spring. Postage is expensiver than the part.
     
  18. Bob Matthews

    Bob Matthews

    Joined:
    Dec 19, 2016
    I too had this problem with the RGM MZ Gold 7" shoes for my Dominator and once they were mounted onto the brake back plate, they wouldn't enter the drum.

    So I took the shoes off the back plate and tried them in the drum to check the contact area. I found the radius and contact area to be as perfect as a fully bedded in shoe, so I just filed away the ends of the shoes where the cam acts until I had a fit. At a guess, I would say I filed maybe 0.5mm off each shoe end.

    Maybe I got lucky because it could easily have been the pivot end of the shoes that was out, but I guess they have been machined to the original Norton hole centres.

    Anyway, I tested the brake afterwards for contact area and was extremely pleased with the results.

    The only thing I would have done differently (I may still have to) would be to file off even more than I did to give a little more free play on the brake lever and to make the brake light switch easier to adjust.

    Update 1 year on and nearly 2 thousand miles covered since fitting - the brake is superb and the rear wheel is lockable with a heavy boot, the play at the lever is now just about perfect.
     

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