Hydraulic handbrake and dual line proportioning valves

[jakesae101]

so in my rally car it has a factory dual line proportioning valve so both lines from the master enter the valve and it splits into the 4 wheel lines there , Now i have wanted to add a hydro handbrake as the factory handbrake setup isnt overly robust but with dual lines after the proportioning valve how do I achieve this i know there are a few options , Not so keen to goto a dual cyl hydraulic handbrake as they are quite bulky and they don't make one that has a long enough handle for where i want to mount it , it will be certed on a MSNZ authority card.

 

The options so far from internets research and thinking 

 

1.T the rear lines togeather and pass them through a standard single master in the hydro and then split them again (i don't know is that legal?)

 

2. use a tandem master with a reservoir like in a standard car and T into each of the rear lines but id need to find something that has equal primary and secondary chambers in it and modify a standard hydro to fit it 

 

3 use a dual piston 4 port master cylinder from willwood or somewhere and make or modify a hydro setup (they are hella expensive ) 

 

so os populace any advice / recommendations ect would be greatly appreciated 

[Rookie]

I would just bin the factory proportioning valve, and get an adjustable one, then run a single rear line through the hydraulic hand brake and then t it afterwards. I don't see any need to keep it factory.

[jakesae101]

id have to change around every line in the car for that as the factory valve splits the system diagonally i think , So i could remove it and feed the primary in the master to the front brakes 

 

then M/cyl secondary >proportioning valve > Hydro > T to rear lines 

 

seems a bit more work than i really wanted to do but i spose there may not be much choice in it anyone know where the best place to get the fittings is ?

[Nominal]

I get my brake bits from ABC in Martin Square in Wellington.

[Valiant]

Is it a disc brake rear end?

 

If it is you could add a couple of extra calipers to the rear and plumb it separately.

[jakesae101]

nope drums all the way on the rear the other complication is id also have to install a residual pressure valve in there somewhere for the dums as it has to be in the prop valve if they are split diagonally 

[KKtrips]

Not sure on how your setup is or what car you are talking about but be aware that your system could be a diagonal split brake system - as in the left front and right rear are on the same circuit and vice versa.

 

(this is always the setup on FWD vehicles and often the case when both m/cyl. lines feed into the same proportioning valve and each wheel is output on a separate circuit)

[jakesae101]

Not sure on how your setup is or what car you are talking about but be aware that your system could be a diagonal split brake system - as in the left front and right rear are on the same circuit and vice versa.

 

(this is always the setup on FWD vehicles and often the case when both m/cyl. lines feed into the same proportioning valve and each wheel is output on a separate circuit)

internets says yes they are in the early mazda 323s and that would make sense why they are all fed through the prop valve 

[KKtrips]

[KKtrips]

So you would need to avoid diagonally split and ditch the proportioning valve then go through the science of figuring out a m/cyl with the correct dual bore and re-run the brake lines.

 

The front brake circuit would be off the the same bore of the m/cyl and the rear circuit would come off the other half which would run a single brake line to the hydraulic handbrake with a T- split after going to each rear wheel

[jakesae101]

bugger might just get a dual cyl cyl and tap each line then

[jakesae101]

ala 

[sr2]

Mate, sounds like a great project but you're rapidly painting yourself into a corner. My feeling is that you're delaying the inevitable which is simply fitting a dual master cylinder, adjustable balance bar pedal box.

I'm ex the automotive brake industry (worked for PBR in Aussie and APPCO Brake & Clutch in NZ)and have been building race/rally cars for the last 20+ years, all I can say is there is a reason why all low tech (i.e. non traction controll/abs) rally cars run this setup.