I have a 1991 Mk2 Golf, and just sorting the brakes. By wiggling the lever gizmo by the rear axle beam whilst pressure bleeding the rear brakes, different flows of fluids happened, so the valve itself works.......... probably. What I am less convinced of is that the levers and springs and things that control it have been properly set up. Any good ideas?

Photo's? links?
Or shall I have a play with it untill the car swaps ends under braking.

Cheers if anybody knows the knack.
Proper setting proceedure (IIRC) is to put the car on all 4 wheels on level ground and adjust the spring so that it there is no free play. However I find that putting just about max pressure on the spring gives very good braking.
Thanks for the tip, theres about a half inch of slack in the setup the now. So I am off to fiddle all about.
:DResult!
Loads of times I've been on greasy roads and the fronts lock too easily, now with the rears working, things are much better.
Although the rear brakes don't do much braking, they do help to get extra weight thrown forward onto the front wheels, more weight, less chance of fronts locking. Once the fronts are doing good things while that immoveable object gets bigger, the proportion valve will react and cut the rears, hopefully before lockup.
Happy!