Here's the deal blokes.

The drum brake master cylinder will have a residual pressure check valve for both circuits. If the master cylinder proves satisfactory, then this must be removed or disabled for the front brakes.

Check the bore size of
The callipers,
The REAR WHEEL CYLINDERS, &
The master cylinder from both the donor car model & the recipiant car model & make sure that the finished product matches the donor car as much as possible.

Datsun 1200 models with disc brakes use a SMALLER rear wheel cylinder to maintain braking balance, so you may suffer rear wheel lockup under hard braking if you do not get it right, Empty Utes suffer more because of the lighter rear.
Do your homework first, think twice, then act.
Chris

there will definitely be something that is the opposite of a pressure relief valve in both curcuits of the master cylinder.years ago,(ok in 1988),i had a brake place do a brake rebuild on my sedan,& they rebuilt the master cylinder with a sedan kit.as the car had disc brakes,this resulted in the car coming to a shuddering stop about a kilometre down the road with the front brakes locked on.not happy.maybe the easiest way is to get this pressure valve removed from the circuit,as this is basically all thats different.a brake place should be able to do this.

The Dual circuit brakes is a 1973+ ish Australian Design Rule (ADR).

So I expect that your 1984 Ute will have a dual circuit system. It is strange that it's 4 wheel drum. I would expect the front to have discs like the 120Y.

Discs have different valving in the master cylinder, I expect you'll end up with slightly dragging front discs, unless you get a 180B or 1600 Dual circuit master cylinder.

You could try and re-valve the existing master cylinder, but it's easier to goto "autopro" and get a costing for a master cylinder rebuild kit for a 1600/180B/200B/240K/Skyline (pick the cheapest to overhaul), and the go buy a 2nd hand master cylinder from the wreckers. Once you've bought it, get the rebuild kit from autopro.

Then re-plumb the existing lines into your newly rebuilt master cylinder. Make sure you follow the new master cylinder F and R markings. The cylinder outputs do not always service the front or rears.

Try and get the Master cylinder from a car with brake fluid still in the reservoir. If they ar eempty, the cylinder can be siezed up, and impossible to overhaul.

Chris

there are two lines coming out of the master cylinder one per reservior, on the side of the master cylinder it's moulded F & R where the lines go into it

there are two lines coming out of the master cylinder one per reservior, on the side of the master cylinder it's moulded F & R where the lines go into it

sometimes dual circuit ones share the same reservoir... So check that there's 2 or three lines coming out of the master cylinder. Sometimes one of the outlets is split into 2 lines.

Single circuit ones only have 1 line coming out of the master cylinder. They are risky because if that circuit fails..you have to rely on your handbrake

Chris

it has a dual circuit master cylinder, To me they look standard tyey are boath round unlike the coupe where one is round and one is square

the master cylinder in the ute is not suited to having discs on the front, you need a dual circuit master cylinder, found in 1200 coupes, or the sunny or even a 120y

Gday,

If its just a std 1200 engine, the the Sunny struts and brakes with no booster will do just fine. Once you start upping power replace your disk setup with stanza, 200B GX (girlock calipers), R31 Pintara, R32 GTR...depending on your budget. You can fit a variety of boosters to accomodate the bigger brakes, which is a must.
Sunny 310 booster, Galant booster are an option here. The rear drums may be upgraded with R31 Pintara. The backing plate which fits the brake assy onto the ute diff needs to have the original mounting holes welded and then redrilled for the ute diff.

I have a 84 model 1200 ute and it is currently drum brake all round , and I found a pair of 80 model sunny front struts which are disk brake, just wondering if my master cylinder is suitable or if I have to change it or if I have to put a booster on it????