AE86 Disc rear end brake Question ?

[BlueAE86]

Hi

I am about to fit a Disc rear end into my AE86 and was wondering the correct way for getting the brake bias correct front to rear?

I hhave read that by gutting the proportioning valve this will work but am unsure as to remove all the springs / valve from both ends ie frt / rear sides or just the rear side ??

I have once befrore just connect a T line into two of the line and a straight through line with the other two and it seemed to work fine but that was years ago and i have heard of just gutting the valave as the way to go ?


Any help would be appreciated.

Cheers

[EVOSTi]

yep best bet is to just get an adjustable proprtioning valve rather than messing with the springs in the factory bias valve. i just gutted my factory valve then added the aftermarket proprtioning valve in line with the rear brakes, does the job.

[LeeRoy]

i Believe PBR make a brake bias/proportioning valve. Im unsure on the cost but i'm pretty sure its the only legal valve available.

LeeRoy

[takai]

There are a few legal ones, and most RTA officials dont care so long as it isnt adjustable from within the cabin. Some want it to be covered over as well.

[EVOSTi]

i think its best to acutally check with your states authorities cause theres alot of 'i herd this' which ill add to by saying i HEARD that in NSW they are legal as long as they cannot be touched from inside the cabin. most people mount them in the engine bay anyway as you only want to adjust it till its good then leave it.

[exquisit]

actually i KNO the best way to get a proper bias is to buy the bias control part from the jap ae86
that way u dont need to screw around with proportioning valves
just plug n play pretty much
not overly expensive n saves time

[Rallystanza]

The other thing is, it is dependant on what discs you have on your disc brake rear. I would presume you have a Jap sepc disc setup??

In my car at the moment, I have standard fronts (working on a solution to that) and 280mm slotted rear discs.

I run an R32 skyline master cylinder, 15/16ths and it has a good amount of rear bias, perfect on the dirt and taily on the bitumen, only under really hard breaking.

So i think my brakes are perfect as i like rear bias and feel i dont need a bias controller...

So what rear discs are you suing and what sort of bias do you prefer/want?

Jeremy

[EVOSTi]

how much would a standard jap spec proportiong valve cost? how much is an adjustable one? you can buy wilwood valves for about $150, i have similar btechnik branded ones for sale for $50 or you can buy other brand proportioning valves.

exquisit, how do you KNOW the best way is to get a factory one? have you used both a factory one and an aftermarket one? i think looking through import wreckers to find a factory jap one is gonna be a whole lot harder than getting an aftermarket one and doing a few stops and setting it up to your own preference.

[terryo]

I recall the Toyota valve is a maximum pressure limiting valve only-it tis there to prevent rear brake lock up under panic conditons, when weight is transferred from rear to front. A proportioning valve like the PBR one, however, has a variable rate to allow for ever increasing pedal forces & hence pressures. They often have 2 or 3 internal springs to vary and control the exact proprotion of pressure that goes to the circuit into which it is plumbed, plus have a limiting valve for the above reason. They work by increasing pressure % to the front circuit as the pedal forces increase. It is for that reason that Authorities frown on them. To set them up requires dynamic testing with purpose built pressure gauges etc. best done on a track. The PBR ones used to come with a warning that it not suited to registered car road use!! . If you have a stock brake system, its best to buy the correct part. Hope this helps

[BlueAE86]

Does anybody have the factory JDM connectors available for sale ??