Ra-celica Brake line flow direction and function

**Toy77** · 09-06-2008, 11:58 AM

Hi guys,

I'm in the process of replacing all my front brake lines and am adding a launch control as well.

For those that dont know - the idea of the lauch control is too allow you to put on your brakes (via pedal), press a switch on the dash (or anywhere) - this locks the brake pressure in the front brake lines leaving the front brakes on. - this makes for easy warming of tyres at the drags in manual cars - and prevents the car creeping over the line while allowing you to concetrate on accelerator and clutch.

The factory system is laid out like below....

With the red lines the front brake system.

Does the proportioning valve (what i have called it) actually proportion or does it just have a brake fail sensor for the fluid level?

The reason i ask is because the front line actually splits before going through the brake propotioning valve. I understand that it may be able to proportion as the pressure would still be the same across all the front lines - is this how it works?

Th enext question and what i am really chasing.... is where to fit my line lock.

This is where i envisionige it - in the front line before it splits...

Will this affect the propotioning valve at all?

Is this how i want it laid out?

Cheers
Stew

**oldcorollas** · 09-06-2008, 01:54 PM

front brakes are not affected by proportioning.. only rear brakes..

the pressure same across fronts.
the proportioning valve uses the front line to "sense" what it needs to do to rear brakes...

dunno if having residual presure in the front lines will cause the rear to stay on.. seems unlikely? but i'm not sure of the internals of the prop valve..

if in doubt, you could have the front line go from master, to prop valve, and than to line lock and T to split off to front brakes...

but maybe is fine where you have pictured?

**Toy77** · 09-06-2008, 03:11 PM

Thanks for that Stu,

if thats how it works then i think it should be fine...

Anyone else with any other ideas or comments?

Cheers
Stew

**SillyCarS** · 09-06-2008, 03:14 PM

that is how mine is set up

not much to the imagination but i can take a photo if you like

**Toy77** · 09-06-2008, 04:27 PM

Hey silly,

So you have a line lock hooked up and working like how i propose to do it?

All works sweet? no dramas with rear brakes doin anything silly?

a pic would be cool......

Cheers
Stew

**BigWorm** · 09-06-2008, 11:21 PM

Why not piss off the standard bias valve & put in an adj. one? They can be picked up for as little as $50 these days, & look pretty.

**Turbo RG** · 10-06-2008, 04:10 AM

this is how mine is done.
just change how the proportioning valve in the pic.

**Toy77** · 10-06-2008, 05:37 AM

Originally Posted by Turbo RG

just change how the proportioning valve in the pic.

hey mate, i'm not sure what you are saying here - that statement doesn't really make sense.

Joel - you got a link to an aftermarket unit?

Do the aftermarket ones still need your front brakes attached or do they just go inline with the rear line and you leave the front and rear lines seperate?

Do the aftermarket one still run your brake fail switch?

Cheers
Stew

**Turbo RG** · 10-06-2008, 05:47 AM

Originally Posted by Toy77

hey mate, i'm not sure what you are saying here - that statement doesn't really make sense.

Joel - you got a link to an aftermarket unit?

Do the aftermarket ones still need your front brakes attached or do they just go inline with the rear line and you leave the front and rear lines seperate?

Do the aftermarket one still run your brake fail switch?

Cheers
Stew

What I'm saying is that your pic is not correct. the proportioning has nothing to do with
the front brakes

**Toy77** · 10-06-2008, 05:51 AM

hrmmmm... ok i see what you are saying.....

BUT on our celicas over here (not sure if yours is different) the front line definately runs through that block as shown. that block does have the brake fail switch located in it it, that may be the reason why the front brake runs through it.

Thanks for your help mate.

cheers
Stew

**BigWorm** · 10-06-2008, 11:51 PM

www.summitracing.com
http://store.summitracing.com/partde...part=SUM-G3905
You should be able to get it from the US for just over $50 with the exchange rate the way it is.

None of the ones I've seen have extra ports for a brake fail switch, besides which my brake fail switch was always mounted on the bottom of the master cylinder?
Then I replaced it with a landcruiser m/c with a low fluid float switch & used that instead.

EDIT: Actually that'll be 60US landed, so still less than most places. But that $25US postage would cover quite a few parts, so the more you buy the more you save, and there are some suprising bargains on there....