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I have a hj / hz proportioning valve and need a brake fail light for the engineer's certificate



I have a LED mounted in the instrument cluster how I think it works is power to the LED and earth through the LED to the terminal on the Proportioning valve when fluid is low it completes the circuit and the LED lights up is this correct or not if it's not can someone tell me how it works as I have tried to GOOGLE it without success
Thanks
BILLY

Billy,

That's how I understand it too - wired exactly like the rest of the idiot lights on an FB/EK (ie power to the bulb, then use the brake master terminal to provide the earth, the same as you use the temperature sender). Make sure you take power from the same place as the other idiot lights (turns off when the ignition is off), not constant 12V.

HQs were a little funkier and used a relay, but same deal. Shouldn't need a relay if you are using an LED. Wiring diagram for the 'Q here:
http://gallery.oldholden.com/Victas-Pla ... 94/album71

Cheers,
Harv

I notice the sender on my 79 HZ ute has two wires and two poles on the sender, I assume the sender acts as a simple switch.

according to that diagram it switches to earth if one side of the brake circuit fails , o power to the globe, earth wire to the switch and you are done.

oz_ek wrote:I notice the sender on my 79 HZ ute has two wires and two poles on the sender, I assume the sender acts as a simple switch.

brake fail switch.jpg

You are correct. HZ is similar to HQ - power to globe, wire from globe to sender unit, them sender unit switches the earth. The only difference is that the HQ sender earths out through the switch body (doesn't need a separate earth wire), whilst the HZ sender sender switch body is insulated (needs a separate earth wire). Wiring diagram is here (switch is item 38):
http://www.mysandman.com.au/forums/show ... ams-please

Cheers,
Harv

i've been told that isn't a proportioning valve also (i always thought it was) but just a switch for the brake fail light

I think if its a 4 port parallel housing its a distribution block. 5 ports, larger internal piston at one end with single line to rear brakes and two in and out for the front brakes would be a proportioning valve i.e. different piston sizes in the one housing indicates biased fluid flow/pressure to either circuits.

http://www.gmh-torana.com.au/forums/top ... ing-valve/

it is a proportion valve/block. Billy, I've been wondering what your brake set up will be, disc/disc, disc drum?......As these proportion valves have different 'crack pressures' depending on the type of vehicle it was originally fitted to, ie: ute, sedan, Statesman, etc.

Thanks for all your comments , it just proves that I can be right sometimes even though my wife says otherwise
oz_ek it is disk front /drum rear and the setup came of a HZ sedan engineer is happy with that and I don't need a brake test as it is a proven system so less expense for me
BILLY

If you do find the rear brakes are locking too soon, try a valve from Statesman, from memory I think the Statesman had a crack pressure of around 450psi

Yeah I did the same research and my engineer told me any valve from a similar sized vehicle is fine-I went torana for memory