Brake hydraulics
It is possible to use the way that the brake lines were set up before. You can either keep
the brake bias valve, and simply use the existing run to where the flexible hose is, or
put a male to male adapter on the line in place of the bias valve.
At the rear, where your brake line terminates at a bracket where the flexible hose is, put
in the flex hose, then connect a short fabricated male to male brake line. This connects
on the beam axle to a 'T' piece three-way adapter, then run a fabricated brake line from
the adapter to each of the brake cylinders. The lines can be formed to match the shape of
the beam axle, and can be held in place using tie wraps or commercially available clips.
At the front, where each of the brake lines run down to the brackets just above the
gearbox, use a male to male connector on each, then use fabricated lines that run along
the bulkhead, and into the wheel arches. Fabricate a simple bracket, similar to those
where the old flexible hoses used to connect, and bolt it into the wheel arch in a similar
position to that of a 33. You then connect the flexible hoses to these. The obvious point
is to not run the brake lines or position the brackets where the wheel or tyres can hit
them, or where the steering arm can rub against them.
Any good workshop or motor factors will be able to make the brake lines and supply the 'T'
pieces etc, all you will have to do is bring in a pattern of the lines, and examples of
the fittings.
This easy way will give you a brake split in exactly the same pattern as before. The only
thing is that it is possible to improve the system by having a diagonally split setup, as
fitted to the later cars.
Diagonally split system
It is possible to improve the system by having a diagonally split setup, with an
adjustable bias valve in the rear lines.
If you take a look at the diagrams that deal with the brake setup of the 'Sud / Sprint,
Alfa 33 1.7IE and my projected setup, you will see some differences.
First look at the Sprint setup, which was how my Sprint was before dis-assembly to install
the 33 suspension. You will note that both front calipers were fed from the front master
cylinder piston, and the two rear calipers from the rear piston. This means that the two
front calipers are equally dividing the fluid of the front piston, and the two rear
calipers share the delivery from the rear piston. While this does not give a diagonal
split, it does mean that for a given master cylinder travel, the balance between the
calipers on each side of the car is equal.
Now look at the arrangement of the donor car. As you can see, both rear cylinders and the
front left caliper are all feeding from the front piston, and the front right from the
rear piston. To me this seems strange. Effectively, for a given amount of master cylinder
travel, the front and rear pistons will be displacing an equal amount of brake fluid,
assuming identical diameters of the pistons. That means that if the two front caliper
pistons are to move the same amount, under the same pressure, then no fluid can be pushed
to the rear brakes. If the rear brakes are moving, then the front left caliper is applying
less pressure than the front right.
My projected arrangement ensures that the front piston is supplying one front caliper and
one rear cylinder, and the rear piston is supplying one front caliper and one rear
cylinder. The rear cylinders are regulated by a pressure regulator in each line. This
system seems to give symmetrical, diagonally split braking.
After having had some questions concerning the brake layout answered, I have decided to
use the setup that I had previously posed as per the third diagram. My only question was
whether a two way adjustable bias valve exists. I was totally unable to find one, so I
purchased a new late 33 standard biasing valve and fitted that.
Sprint 16v brake system
setup schematic
My projected arrangement ensures that the front
piston is supplying one front caliper and one rear cylinder, and the rear piston is
supplying one front caliper and one rear cylinder. The rear cylinders are regulated by a
pressure regulator in each line. This system seems to give symmetrical, diagonally split
braking.
After some discussion with various persons on the 33 Discussion Page (see favorite links),
this seems to now be more or less definitive. The only outstanding item is the issue of
what biasing valve to use. As was mentioned by one of the guys on the discussion group,
two separate bias valves may be more trouble than they are worth.
Other issues concerning the brakes
My ideas for the brakes so far have covered only the hydraulics and the general layout.
Nothing has been said so far regarding the calipers and drums themselves.
I overhauled and refitted the Alfa 33 1.7Ie brake components. This means the single
piston, sliding yoke caliper acting on a solid disc at the front and a standard twin
leading shoe drum at the back.
I have fitted new seals to the caliper pistons, and used new discs and EBC 'Green' brake
pads. In addition, Aeroquip braided hoses are used.
At the back new cylinders have been installed, and I will probably end up replacing the
shoes and drums with new, though that will force the use of new bearings and stake nuts to
complete the job properly. I will investigating the costs of this.
Further down the line, it may be worth considering the vented front and combination disc /
drum arrangement employed on the 16v QV 33 models. The economics of that will be studied.
Anyone who has experience of fitting this arrangement to an 8v is invited to e-mail me to
tell me whether it was worth it, easy, expensive, etc.
