I suppose I'll have to check the clutch rod now, but if it ain't broke.....
D

Having checked the WSM again I think I CAN explain why the push rods are unequal in length - free movement on the clutch pedal is specified at only 3.9mm vs 13mm on the brake.

Thanks Marty.
I have used the "wheel on" method, as it gives more leverage against the drag of the drum.
I solved the problem by (quite significant) adjustment of the piston rod. This brought the pedal up to where it should be and I set the correct amount of "play".
2,500 miles on, the brakes are still ok, but I will adjust them soon. I know at least one rear drum could do with a skim, so I'll probably do the lot.
No problem with the brake's power even on the Autobahnen, but I had one heart stopper when the pedal took up the free play and suddenly went in about 1/2" without anything happening when I hit the brakes hard in a town! I continued a bit gingerly, but it didn't do it again & all is still good. Maybe a small air lock clearing?
David

According to the workshop manual (Issue 2) there should be only ½"(13mm) free movement of the brake pedal before the piston in the master cylinder begins to move. The clearance can be felt and observed if the pedal is moved by hand. (Provided you are flexible enough to lie on your side in the footwell!)

The actuating rod between the pedal and the piston is adjustable in length, although this was set when the car was built and should never need adjustment - however, who knows whether it has been altered since?

In fact, I had this problem after removing the master cylinder to have it re-sleeved. While it was away being repaired I managed to mix up the clutch and brake actuating rods which (for reasons I do not understand) were different lengths. I can attest to the fact that it is incredibly difficult to adjust these rods in situ. (Its difficult enough just to photograph them)

Try adjusting the brake with the wheels on. Set up with the hole in the drum lined up with the hole in the wheel, then adjust, this gives you the best result.

Marty

Having released lots more power(!) with the ZB manifold I had a look at brake adjustment. I think the standard drums should be fine. I have good wheel cylinders and linings, the drums are all round & true. My problem is I think there is too much free play at the pedal ( 1" - 1.1/2" before anything happens.
There is no air in the system. The Master cylinder is in good order as well.
The brakes are ok, but need a good push, and because of the initial free play, do not inspire confidence, but always do work!!
Any advice?
David