Hello,
I think the innerds of the example shown by my Dad are probably based on a Jack French design that he proposed back in the early 80's. I have the 750 bulletin with the article in it and will try and dig it out.
I think for the amount of effort involved in making special Cams etc to modify the standard brakes you still might only achieve as good a system as a girling set up.
To achieve twin leading shoes on a the girling brakes you need to make new actuator blocks so that each takes one plunger and one falcrum. If you are going to do this mod you may be best off making your own backplates as Bernard did.
The next thought along the path is if you have the time and equipment to make backplates should you make bigger drums? I must admit if I was driving the Austin Riley that was at Kop I would want bigger drums at the front.

If anyone can get a copy of "The Modern Motor Engineer Vol3" then on page 202 there is a nice description and illustration of the Girling two leading shoe arrangement. It is an evolution of our Girling system whereby the second shoe is actuated by a system of bellcranks and a strut. The expander or actuater pushed directly on the first shoe, whilst it pushes a bellcrank for the second shoe. The bellcrank operates a strut that pushes a bellcrank down were the adjuster is located therefore giving two leadig shoe braking and easy adjustment.
I'm not sure if this would fit in our drums given the lack of room, but it would certainly be neat and effective?
It is a poor picture in an old book, so photography is'nt really working which is a shame as it looks much better than my description!!!

Steve

My front brakes are based on TLS motorcycle design. Before the Austin I built an MV Agusta motorbike and converted the brakes to TLS using an Italian drum. The design was ideally suited to the Austin so I used the same ideas and machined back plates, cams, pivots and arms to suit. The MC shoes were the correct diameter but too narrow so I managed to pair the shoes so they work side by side. Which means four shoes per axle. They are magnesium, again a reason why I used the MC shoes. I'll try to find a few more pictures. I kept the standard Austin dia' but they could easily be made larger.

A few pictures, showing the brakes as fitted, components during machining and also the rear shoes.

Very nice work. How well do they stop the car?

The shoes look machined in one photo and cast in others - or am I mistaken?

Thanks

Charles

Cars yet to run so I don't know if they work!!!!

I might yet go back to Semi Girling!

Machined shoes are on the rear these are just standard set up, fronts are cast magnesium.

i am responsible for manufacturing the brakes on the ulster at kop hill
the car has raced all season with no adjustment necessary
the brakes have fully floating shoes so all the lining contacts the drum,, not like the original austin setup

if you want any info feel free to ask..

Hi Ian,

I would be interested in any information yo are happy to post!

I guess the main questions are is it a worthwhile improvement - worth the effort; is it a lot of effort to create!

Are you the person I have heard of in Bourne End?

Many thanks

Peter

yes its me from bourne end, there are 2 of us involved with building A7's but i am not the one silly enough to drive the thing round the track,, i do the metal bashing stuff..
the modification is not hard, bit fiddly perhaps.
the improvement is huge.. on a normal set up about a third of the leading shoe contacts the drum effectively and the same with the trailing shoe..(not that the trailing shoe does much)
because the mod gives you 2 floating leading shoes you get so much more material in contact with the drum.. the mod is difficult to describe here but if you are serious about doing it you could pop in to bourne end or i can give you my phone no.