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Rear brake plate

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I have just been cleaning the rear brake plate on my late 60s Sherpa and noticed that one of the boss' for the brake shoe pin is cracked in 3 places. I don't know whether the wheel is original to the bike so pic of plate 

I suppose it may be possible to get it welded but I think I would be happier with a better one.

Thanks, Keith.

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The brake plate is the correct one for an early Sherpa. The two pivot post anchors should have a small brace plate bit like an oversized chain link plate fitted on after the shoes, without you can get cracking. From your picture it may be that some one has tried to force the pivot post in without preparing properly and caused the cracking. The plate is made from reasonable quality cast alloy and should weld nicely given correct cleaning prep etc. You may also want to inspect the brake quadrant spindle as this will most certainly be worn in the brake plate as there is no bush. I have just made a bush and reground the spindle to effect a reasonable smooth fit without any slop! If your brake drums are badly worn ( cast iron liner/sleeve ) then Villiers Services can supply thicker oversized brake linings for £20🙂 You need to take a few easy measurements and they do the rest, good service and less costly than some others. If you have chromed brake drum linings then it’s more complicated. My M80 is 1972 and I’m pretty sure your bike will have cast iron brake drum lining. Lining refers to the surface that the brake shoes rub against and not the shoe lining material.

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I would think you could pick up one of those brake plates from a wrecker fairly easily. If you are stuck post up the important dimensions and I'll have a look to see if I've got one spare (axle diameter, drum diameter and a photo showing the outside)

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Thanks SS. First off the drum is worn and the shoes are now on their way to Villiers for the thicker linings. The Quadrant spindle has slight wear but not too bad.

There was no chain link on the pivot posts, just a circlip on each. I'll ask around to see if anyone does small one off tig welding jobs locally. Is the post a press fit into the plate? If so that would need sorting as it just drops out at the moment. Maybe I'm being overly cautious but I still think I would prefer a good used one on such a critical component though.

Feetup, Thanks for the offer and I will certainly keep you in mind but if I can't get mine successfully repaired I will hopefully, as you say, be able to find a replacement in this country. Postage from Australia could possibly make it a bit expensive.

Keith.

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The pivot posts are an interference fit and hence the cracking caused by corrosion and brut force at some stage. The two posts can be left with their own individual circlips but the link helps increase support. Two washers welded together OO would do nicely. The brake plate anchor post is not that critical on a Trials bike as the speeds are low, it’s probably been cracked for years and held by the shoe, so it’s not going anywhere. You may find a plate in good nick, but it will be probably just as old and have it’s own faults; but yours welded ( by TIG) and then bored to size will be good, you will have the satisfaction in knowing it’s a good job. Fit the post back in with stud lock or similar if going the weld repair route.🙂

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On 07/04/2018 at 9:07 PM, section swept said:

 Two washers welded together OO would do nicely.

Why not just a strip of 16swg or 1.6mm steel with two holes drilled. This would be far stronger than welded washers. Easy for me to say that as I have access to a workshop full of off cut sheet steel. (stored behind the laser cutter..........now thats an idea)

Stuart

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9 hours ago, twinnshock said:

Why not just a strip of 16swg or 1.6mm steel with two holes drilled. This would be far stronger than welded washers. Easy for me to say that as I have access to a workshop full of off cut sheet steel. (stored behind the laser cutter..........now thats an idea)

Stuart

Yep that’s a much better engineered way of doing it, but I wanted to explain the shape. Then of course welded together followed on. I too once had access to a very similar supply of ‘free’ steel, but alas no more☹️

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