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Norton 16H read brake pivot bolt

Submitted by paul_gooch on Sat, 16/03/2013
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I'm having issues with my rear brake, there is some play between the pivot bolt and the frame casting.

Initially I thought that the problem lay with the pivot bolt itself, worn thread was my diagnosis, it looked a little chewed up anyway, so I replaced it, and had the same issue.

Now it appears the thread within the frame casting itself may be suspect, in fact, as often happens when you really start to look closely at these issues, it seems the problem is more complex, as the thread doesn't even run true, so the pivot bolt goes in at an unhelpful angle, causing the brake pedal to slightly foul the primary case in operation.

I wonder if anyone has a remedy? Of course I could strip bits off, weld up the hole, drill and re-tap it, but it sounds like a rubbish job when someone may know an alternative?

If anyone knows the tap size that would help as a start, I know it's 1/2 inch, but not the pitch.

Cheers

Paul

Submitted by dave_graham1 on Sun, 17/03/2013

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I took my pivot bolt that was worn, and the brake lever, and had a new bolt made the same out of stainless and the hole in the lever sized to match. I did have to slightly bend the lever out to miss the chain case as it was very close. But if your problem is that the lug on the frame is bent, this wont solve it.

Submitted by paul_gooch on Sun, 17/03/2013

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Thanks Dave, I thought it might be too, but a 1/2 x 26tpi nut wouldn't fit it. Late last night I remembered I had a thread repair file and managed to match up the 20tpi thread, so at least I then knew it was UNF.

The good news is that I have solved the problem, as I found a 1/2 x 20 UNF helicoil repair kit on ebay. The kit includes a drill, to drill out the old knackered thread, a tap for the helicoil insert, and five 1/2 x 20 tpi inserts. It can be done in situ and saves me a headache so at £20 including postage it seems like a good option.

Thought I would post details in case any other folk have similar issues.

Submitted by paul_gooch on Mon, 18/03/2013

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Thanks Gordon, you're right, it is 20tpi cycle, but I somehow doubt I would ever get a helicoil kit that is BSCy, I bet they'd frown down the phone at me :)The 20tpi UNF helicoil won't perfectly match the cut of the thread on the pivot bolt, but it should eliminate the play, and once in situ I'm not taking it out again, until it falls out, so it should suffice (the rivet counters won't like it)Paul

 


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