Brakes

The brakes have been a bit of a trial for me, there are so many permutations even if you stay with the original mechanical systems. My system is a mixture of Bowden mechanical at the front and an early A7 mechanical system at the back. The brake drums are of two different types. The front brake drums don't fit the back and vice versa. The front brake shoes (3off) were missing and as far as I can ascertain are unobtainable. I decided to get a set of eight s/h alloy 1 1/4" and  move on  from that point and make everything fit.

Rear brakes

The cams at the back were not even running in a brass bearings, just holes in the forging and seized at that. As these were badly worn these had to be drilled and bushed and reamed to size. The cams that were initially supplied, were the wrong type and had to be changed again for an earlier type. This of course results in another strip down of the hub carrier.

Rear brakes connected up and working

Front brakes

The front brakes were another  challenge, requiring the 1) fabrication of a new back plate. The standard A7 oem back plate had to be cut away to accommodate the Bowden forging protrusions and mounted on the back to make room for the non standard brake drums.  I have no idea what the drums are off but they do not fit the Bowden assembly ideally.  2) The  pivot point for the brake shoes had to be moved to accommodate the smaller A7 alloy shoes. 3) I had to increase the internal contact width slightly and fit a 2mm spacer on the wheel studs to make them fit with the 1 1/4" shoes. The drums were also well off the concentric being about a mm of wobble. This had the effect of locking up the brakes. 4) The drums were trued up on the lathe.  The front brakes, now at least, go together and look as if they may actually stop the car.

 



Front drums fit after truing up on lathe

Hand/foot brake

The handbrake started out devoid of modifications other than shortening the leaver to allow it to reside under the bulkhead. I tried the standard parts for the Bowden cables operating the front brakes but was hugely disappointed by the lack of any fine adjustment. I can see the rear bakes have this problem but the front brakes are somewhat more critical as 80% of the effectiveness comes from them. I decided to modify the balance bar and add a full length cable from an Austin Maxi.



Modified balance bar to front brakes

Previous adjustment

Previous balance bar arangement

Update 4th Aug 21

I have subsequently updated the brakes to hydraulic twin leading shoe at the front and single leading shoe at the rear, the brake liners have also been updated to Mintex high performance racing material.

Here is an Index page for the build