Page 1 of 1

Rear brake lock-up

Posted: Wed May 06, 2026 10:09 pm
by Geoffrey Lord
Hi,

Has anyone a fix for the self locking rear brake on my '53 VB plunger? I can apply the brake quite hard and it's fine but then other times a touch on the brake pedal to scrub off a little speed and the whole shebang locks and the lever is sucked from under my foot. Quite scary! I have tried stronger shoe springs and different settings of the conical adjuster, I have even tried an additional, temporary return spring on the lever itself.

Is shoe material a factor? I have ones with the embedded brass (?) elements.

Re: Rear brake lock-up

Posted: Wed May 06, 2026 10:29 pm
by Pete.Silson
Have you got a downward pointing brake arm (like the first picture)?
downward brake arm (dangerous).jpg
If so, then this is a well known problem and can only really be cured by changing to an upward pointing brake arm.
upward brake arm (safer).jpg
I am fairly sure both the pictures above are of 1953 Anstey Ariels.

Pete

Re: Rear brake lock-up

Posted: Wed May 06, 2026 10:35 pm
by Geoffrey Lord
OK, That is interesting! Yes, it is downward pointing. I wonder why changing to upward pointing works?

Geoff

Re: Rear brake lock-up

Posted: Thu May 07, 2026 7:37 am
by Vincent.vanGinneke
The combi of the plunger springing and the direction the cam on the lever pushes the shoes makes for a self servo action when the rear brake is applied.
A factory mistake !
Routing the rod with the arm pointing up is a bit difficult, some models used a cable after this was found out and you need abutments for that I think only the later SQ4's had that.

Re: Rear brake lock-up

Posted: Thu May 07, 2026 9:58 am
by Geoffrey Lord
Thanks for that, it all makes sense now. I will work out a fix.

Cheers

Re: Rear brake lock-up

Posted: Mon May 11, 2026 7:24 am
by simon.holyfield
Geoffrey Lord wrote: Thu May 07, 2026 9:58 am Thanks for that, it all makes sense now. I will work out a fix.

Cheers
When you make the brake rod for your new upward pointing arm you will find the routing quite difficult I have multiple small bends in mine to get it around the suspension and the brake light switch but once it's sorted it works pretty well. It's not quite as solid as a properly straight brake rod but it's perfectly acceptable.

Shout if you need pictures.

Re: Rear brake lock-up

Posted: Tue May 12, 2026 3:57 pm
by Roger Gwynn
All 53 plunger models have a cable operated brake. See the full story here. https://draganfly.co.uk/product-categor ... -sprocket/