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Early BN1 Narrow Brake Drum Identification

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zblu, i just spoke to john at sports and classics he explained to me that the part number on early model bn1 is 1b4276, for front and rear, i was interested because ive been trying to nail down the year of a front end that id gotten a couple of years ago it turns out my parts are from a bn2. drum p.n. 1b4483. ya those cast numbers are hard to read!
 
Thanks for the confirmation anthony7777, I'll get the wire brush out and confirm!, do you know the max I.D that these can be taken out to before replacement is required?
 
zblu, ill try and find out for you, but check me on this one, i think i read someplace that these drums are surface hardened and should not be cut. nitrided? .025?- anyone? dave?
 
Thanks anthony7777,
Think what I am looking for is the original I.D. of the drums, as the donor car i have acquired has been in a farm shed for the last 18 yrs at least, maybe longer (given the 3 pairs of antique female bloomers I found under the drivers seat!, think they might be Kitty's from Gunsmoke fame!)
Car is not a BN1, but has lots of parts common, even early radiator as shown in w/shop manual
 
anthony7777 said:
zblu, ill try and find out for you, but check me on this one, i think i read someplace that these drums are surface hardened and should not be cut. nitrided? .025?- anyone? dave?
Click to expand...
I have only my experience to go by. Yes - The original drums were reportedly surface hardened. My BN2 brake drums at 85,000 miles, showed absolutely no wear or out of round & needed no truing. They "must" have been hardened. I DID replace the shoes with carbon - Kevlar lining which made a remarkable improvement, though not cheap. The new shoes were "arced" to my 11.005" drum diameters.

I guess my feeling is that if the old drums "need" grinding, it would be better to replace them.
D
 
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