Hi, sadly it has now been six years since I had to say goodbye to
my '82 Cloverleaf so I cannot speak specifically about there
operation on the Sud but, generally, my understanding of load-sensing
brake limiting valves:

With the rear of a vehicle unloaded - thus no actuation of the lever
arm of the valve - the valve will be providing its maximum limiting,
i.e. minimal braking, to avoid locking the lightly loaded rear wheels
before the more heavily loaded fronts.

As the vehicle is loaded, and the suspension compresses, the lever
arm of the limiting valve is actuated resulting in a reduction of the
limiting effect of the valve and thus allowing increased rear wheel
braking.

Steve



--- In sprintformation@yahoogroups.com, Graham&Joan Hilder
<graham.joan@...> wrote:
>
> Hello again Martin,
>
> When you say, "I therefore assumed it could only seize in the off
position
> if the rear of the car was left up on axel stands with the rear axle
> hanging", you're exactly right, which is why they never do seize in
that
> state, but always in an on or partly-on state, in which you have
full or
> nearly full braking available at the back. I just had a quick look
under one
> of our Suds, and found that, with the car empty and at rest, the
> valve-actuating lever was not pressing against the valve at all,
suggesting
> that the valve was completely relaxed and providing full rear
braking, i.e.
> that any limiting would not start until the rear suspension started
to rise
> above its static and empty level. I guess the rear brake pistons
are of
> such small diam that no limiting is needed until this happens.
>
> And when you say, "with our Citroen GS`s ...We used to load up the
boots for
> the MOT to make sure the rear callipers were doing some work",
well, if my
> observations under my Sud tonight were right, that wouldn't help in
a Sud,
> as even with my car empty the valve was already supplying no
limiting, i.e.
> max braking. It'd be interesting to make some proper tests with
jacking up
> and loading down the suspension and observing how the valve
actuating lever
> reacts.
>
> Best rgds,
> Graham in NZ
>
> >>>>>>>
> Martin wrote...
> I always assumed the valve was progressive. That is, when the car
was fully
> laden with rear passengers and a full boot it was 'off ' and when
braking
> very hard unladen was 'on' to prevent rear lock up. So under light
braking
> with no extra load it was about half on (or half off) and this was
why the
> rear disks rust, as most of the time there is no extra weight on
the rear
> and so rear braking effort is always partly restricted. I therefore
assumed
> it could only seize in the off position if the rear of the car was
left up
> on axel stands with the rear axel hanging...
> ...with our Citroen GS`s...We used to load up the boots for the MOT
to make
> sure the rear callipers were doing some work.
>