A picture being, so they claim, worth a thousand words [if it’s the right picture] … would I be correct in assuming that Fig. 3 here is the beast in question ?

.

**LINK**

http://www.da7c.co.uk/technical_torque_articles/braking_efficiency.htm

MichaelG.

Austin 7's have brakes? Holy moly, I never noticed on mine (all those years ago).

Martyn, what year / model ?

Bob

Hello Again All

Thank you so much for the responses. Such a diversity I'll respond by name if I may.

Nick – exactly. BK20.

Michael – that's the adjuster outside the chassis side rail that you use to adjust (as best you can!) the back brakes. Remember, we're discussing the uncoupled version where there's no connexion between front and back!

Duncan – Not quite sure how you would use the 'long thin tool' as I think you'd be entering the work on the centre line (axis). So would you be using the four jaw to offset and create a different axis? That said – the cheat is brilliant. I'd thought about it. I guess many people would throw their hands up in horror at the suggestion of silver solder on a brake part. But I think brazing would be absolutely fine.

Speedy – That's for coupled brakes and I have a box full. Interestingly, I modified one to use on the pivoting plate of the uncoupled system. It works, but it's too thick to allow the plate (clearance between it and the chassis member) sufficient movement to pull the brakes on. Date and model not relevant here, of course, as pre 1930 A7s had uncoupled brakes (remarkably!) PS Radiator cap worked out fine. It's certainly not perfect, but the very uninitiated probably wouldn't know it's not 'factory (or some factory) and it's better than the 'ole.

Old Mart – If it's not too much trouble and you forgive me being daft; could you talk me through?

Thanks again everyone.

Martyn Sunny/hot in Paris. No riots!

If there was any doubt, lightly countersink the main part on the other side to the button and peen over the shaft. If there was a failure of the solder joint, the shaft will just rotate and cannot come out.

That’s strange … I had deliberately chosen Part.1 of the set, because I thought it specifically mentioned the earlier version.

Ho-Hum … must try to get more sleep.

MichaelG.

My only suggestion for making BK20m would be to turn a complete didc, and to produce the groove for the cable using a round toolbit of the correct diameter, ground to act as a cutting tool.

Having produced a "pulley" like component, then cut out a scetor of a suitable size and then make and fit the headed pin to it.

Howard

Martyn

You could make it as one part.

Turn the outer diameter and then the groove for the cable either using a custom tool or a profiling tool.

Then offset the part in the 4 jaw and turn to the outside diameter of the lug. Then turn the smaller diameter of the lug using a parting tool or a custom made tool.. Reset the part in the 4 jaw and part off (the large diameter).

Then cut off the unwanted part to make the crescent and file to shape or if you have a mill, use that.

I am no expert, but that is what I would do.

Stuart

If you can't buy the bits you need from one of the A7 parts suppliers, why not wait until the Beaulieu autojumble? I know it's probably a few months away, but I bet you get get a list of other bits you need to make it worthwhile. It's also been a few years since I last went to the A7 national show at Beaulieu, But again, well worth a visit. I don't know when that show is on either.

Are you in Paris? A long way to Beaulieu, but I have seen many French paople and cars when I used to go.

I don't understand why having it in a small 4 jaw is a problem, take it out and put it in the big one. You've got to reset it anyway.