BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: Dibble on 08 Sep, 2024, 10:32

Title: Warped brake casting?
Post by: Dibble on 08 Sep, 2024, 10:32
Is it possible  for castings suCh as the rear brake drum (67 HORNET) to become distorted over time? The one aquired for latest pr.oject seemed excellent but when fitted to swing arm i noticed it definitely wobbles! Checked stub spindle  and its a new bearing fitted correctly by hydraulic press etc. Thought it was sprocket at first so removed and checked again-no joy! Is it possible to have it .re-machined do you think? Any thoughts gratefully recieved.
Dave.
Title: Re: Warped brake casting?
Post by: cornishbob on 08 Sep, 2024, 10:58
get another one
Title: Re: Warped brake casting?
Post by: LightningAndStarfire on 08 Sep, 2024, 12:37
Is it the cast iron brake drum you have? Together with the crinkle hub?

I would rather suspect the spindle and / or shaft. Disassemble and try to find the culprit with a dial gauge . If you do not have a dial gauge, the cost to buy can be less than new parts.
Title: Re: Warped brake casting?
Post by: rhyatt on 08 Sep, 2024, 13:41
doesn't the brake plate get nipped up when all the rear wheel spindle nuts are tight ??
most of my backplates wobble a whisker and this is useful to centralise the brakes when putting wheels back (put brake on , hold it on, nip up wheel nuts
Title: Re: Warped brake casting?
Post by: cornishbob on 08 Sep, 2024, 17:02
suppose it depends how much wobble you call a wobble. now my missus has a wobble that......oops!! apparently i'm not to say that.

surely there must be a specification for acceptable runout listed somewhere in the manuals

ride it and see if you can feel movement in the brake pedal with GENTLE pressure being applied.

is there uneven wear on the shoes?
Title: Re: Warped brake casting?
Post by: DAVE BRADY on 08 Sep, 2024, 19:24
Hi,

As rhyatt suggests.  If you just have the brake drum etc in place the wobble will be the tolerance in the bearing which will be detectable at the sprocket.  When the wheel is in place and tightened up the wobble will go.

Dave.
Title: Re: Warped brake casting?
Post by: Dibble on 09 Sep, 2024, 08:23
Thanks to all for your most useful information. I do own dial guage etc and i will check what i can. The thing is i have 3 similar A65's and its first time ive noticed it! Suppose this is what makes it fun eh! Thanks again.
Dave