(74 Mk2) brake caliper - wear indicator - ???

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joe czech

joe czech

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i'm rebuilding my brake caliper, and mine has, what appears to be, a wear indicator. i'm not finding it in the parts book or in any rebuild instructions. it appears to be just a thin (stainless) sheetmetal part held on with two small screws. it looks like as the pads wear, the inner surfaces would ride against the rotor. is this an aftermarket mod or maybe a Mk3 feature?

(74 Mk2) brake caliper - wear indicator - ???
 
Factory mod introduced during 850 production and pre MK3, it's a scraper to remove the rust, my MK2A has it and there is a service bulletin explaining its function somewhere.

From RGM who still stock them, apologies for the caps but that's RGM text.

INTRODUCED BY NORTON IN 1973 AND USED ON THE PRE MK3 850 FROM ENGINE NUMBER 307311, BASICALLY 850 MK2 AND MK2A MACHINES HAD THIS SCRAPER FITTED ON THE LEADING EDGE OF THE CALIPER, THE IDEA BEING TO HELP REMOVE WATER FROM THE DISC. CALIPERS WITH THIS ADDITION CAN BE IDENTIFIED BY THE TWO SMALL HOLES ON THE LEADING FACE OF THE CALIPER.
 
thanks kommando - good to know. so, I've got to ask - does it work? seems to me, much like a car, the brake pads would remove the rust through normal use - ??? :)
 
No it doesn't. It will squeal if it's touching the rotor. Can be very annoying. Mine is there, but I've spread the ears out to where it doesn't actually touch.
 
They only work for a short time before they wear out, hence the slotted holes. I keep mine for originality only, it's on the caliper and if I ever refit it instead of the Lockheed racing caliper it will be set not to touch.
 
And it doesn't show on the AN drawings, so I'm not sure which way it mounts. I have mine mounted with the ears facing downward, not inside the caliper. Anybody know for sure?
 
maylar said:
Interesting. So it seems the intent was that the thing be "free floating" by not tightening the screws all the way. Maybe that's why mine squealed.
Click to expand...
mine wasn't free floating, and the "ears" were on the inside. what is the correct orientation? commando mentioned a service bulletin - anyone have a copy of it?
 
joe czech said:
mine wasn't free floating, and the "ears" were on the inside. what is the correct orientation? commando mentioned a service bulletin - anyone have a copy of it?
Click to expand...

Now that I think about it, mine has always faced downward (outside of caliper), and I'm the original owner.
 
joe czech said:
what is the correct orientation? commando mentioned a service bulletin - anyone have a copy of it?
Click to expand...

It's further down the thread in the link I posted and it fits as shown in the first photo of that thread because it's a scraper.
 
The condition of the screws leads me to think that a PO did a very poor job of re-installing the piece...You don't need it, it adds a fail point, and, as others have mentioned, can produce an annoying/distracting auditory component.

With a properly functioning brake system and new pads and regular maintenance, of course, you will have plenty of time to worry about something else...

K.I.S.S. is an acronym that applies rather well in this case, many others too.

Best
 
I seem to be in error. my scraper was not installed as shown in my original post, but opposite - the ears are facing outward as other have stated. sorry....
 
My MK2 had it when I restored the caliper two years ago. It was "blued" along a part of the contact edges. I never re-installed it. My brakes have been great (Fedoro Platinum pads with the Madass re-sleeve kit on the MC). I did need to go back at the caliper after a few test rides to add some anti-sequeal "paste" to the pad/piston/caliper contact points....all sequealing gone.
That scraper seems like it could cause a problem if it were to come loose while riding and has no real benefits. Toss it!
 
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