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Over thickness brake linings ?

Norton Models (not Commando or P11)

Over thickness brake linings ?

Postby Rohan » Mon Feb 13, 2017 9:43 pm

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...

Image

Makes a change from the usual worn out stuff......

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Re: Over thickness brake linings ?

Postby Burgs » Tue Feb 14, 2017 1:20 am

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.

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Re: Over thickness brake linings ?

Postby Fast Eddie » Tue Feb 14, 2017 1:21 am

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!
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Re: Over thickness brake linings ?

Postby Rohan » Tue Feb 14, 2017 2:21 am

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 ?).

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Re: Over thickness brake linings ?

Postby L.A.B. » Tue Feb 14, 2017 2:47 am

Fast Eddie wrote: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.

Rohan wrote:Steel shims ??
I thought that was only a bodge for worn out linings ?


What Eddie is referring to are the shoe 'slippers'.

https://andover-norton.co.uk/en/shop-de ... oe-slipper
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Re: Over thickness brake linings ?

Postby Rohan » Tue Feb 14, 2017 4:21 am

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 ?

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Re: Over thickness brake linings ?

Postby Rohan » Tue Feb 14, 2017 4:27 am

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).

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Re: Over thickness brake linings ?

Postby L.A.B. » Tue Feb 14, 2017 6:23 am

Rohan wrote: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).


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-

REAR BRAKE SHOES (PR) 7" (06.0828, 06.0013, NM16547, NM19584, A2/443, A2/444)
part-no: 06.3417


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.
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Re: Over thickness brake linings ?

Postby Triton Thrasher » Tue Feb 14, 2017 12:01 pm

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.
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Re: Over thickness brake linings ?

Postby xbacksideslider » Tue Feb 14, 2017 1:45 pm

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.
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Re: Over thickness brake linings ?

Postby norton bob » Tue Feb 14, 2017 2:06 pm

High friction MZ GOLD linings.

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Re: Over thickness brake linings ?

Postby Rohan » Tue Feb 14, 2017 4:15 pm

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
Image
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...

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Re: Over thickness brake linings ?

Postby L.A.B. » Wed Feb 15, 2017 2:56 am

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


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.




Rohan wrote: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 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.
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Re: Over thickness brake linings ?

Postby Rohan » Thu Feb 16, 2017 3:48 pm

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....

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Re: Over thickness brake linings ?

Postby Rohan » Sun Feb 19, 2017 3:09 pm

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...

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