Jump to content


LC / LJ Proportioning Valve


  • Please log in to reply
6 replies to this topic

#1 _LHoon_

_LHoon_
  • Guests

Posted 20 June 2009 - 04:35 PM

Hi guys, I want to tidy up my engine bay in my LC. It currently has a 7" booster, standard LJ master cylinder and standard proportioning valve.
Can I get rid of the proportioning valve?

The car has a holden V8, with HQ discs on the front and R31 skyline discs on the back.

#2 _Squarepants_

_Squarepants_
  • Guests

Posted 20 June 2009 - 05:09 PM

Yes you can, with discs on the back.
You should have already disabled the prop valve (by removing the poppet inside) if you've been driving it.
It will take some replumbing of brake lines, but by all means, piss it off!
Unless of course you get rear lock up before front, in which case I'd recommend an adjustable prop valve. These do not hold residual pressure in the rear lines like the stocko ones do, they just limit the pressure going to the rear lines.

#3 dattoman

dattoman

    Do I feel lucky? Well, do ya, punk?

  • Administrators
  • PipPipPipPipPipPipPip
  • 16,471 posts
  • Name:Neil
  • Location:Perth Western Australia
  • Car:LX SS , 76 Cadillac , 3 x dattos
  • Joined: 04-February 07

Posted 20 June 2009 - 06:10 PM

An LC doesn't have a proportioning valve
However it does have a diff pressure switch
Unless yours had the HQ one fitted when they did the HQ brakes

You still need to retain the warning switch but I guess you could hide it somewhere else

#4 ls2lxhatch

ls2lxhatch

  • Members
  • PipPipPipPipPipPipPip
  • 5,332 posts
  • Location:Perth
  • Car:LX Hatch
  • Joined: 29-May 06

Posted 20 June 2009 - 10:59 PM

As Dattoman said if you have one of these then it is a distribution block and brake fail switch. It is not a proportioning valve.

Posted Image

This is the distribution block, brake fail switch and proportioning valve from an LX.

Posted Image

The brake fail switch is a requirement of ADR 31 which was not introduced until 1 Jan 1977. Therefore you may not be required to have the brake fail switch on the LC. It would be worth checking with an engineer.

If you are not required to have a brake fail switch you will still need a distribution block for the front brakes. This adjustable proportioning valve and distribution block may be suitable. The switch on the proportioning valve is a brake light switch.

http://www.summitrac...arts/SSB-A0730/

Edited by ls2lxhatch, 20 June 2009 - 11:03 PM.


#5 _LHoon_

_LHoon_
  • Guests

Posted 21 June 2009 - 10:01 AM

As Dattoman said if you have one of these then it is a distribution block and brake fail switch. It is not a proportioning valve.


Ahhhhh, ok yes then I have one of these. That is what I was referring to. :-)

Datto - All I have is a standard disc brake (LJ) m/cylinder and distribution block.

Squarepants - yes I have already removed the poppet from inside the m/cyl fitting.

#6 _LHoon_

_LHoon_
  • Guests

Posted 21 June 2009 - 12:04 PM

Is there a way of getting rid of the distribution block completely? Are there any master cylinders with two outlets for the front brakes?

If not, I guess I will just hide it under my guard. Got any pictures of a neat brake line setup?

#7 ls2lxhatch

ls2lxhatch

  • Members
  • PipPipPipPipPipPipPip
  • 5,332 posts
  • Location:Perth
  • Car:LX Hatch
  • Joined: 29-May 06

Posted 21 June 2009 - 12:51 PM

There are a few master cylinders with dual front brake ports, intergrated prop valve and brake fail switch. You will need to modify the master cylinder bolt pattern on the booster to suit.

Posted Image

There are also few aftermarket master cylinders that have ports on both sides and you block off the ports you do not need. Although SSBC specifically recommends against using both ports on their master cylinders. I do not understand the logic.

You can connect your brake lines to the ports on either side of the master but do not use both sides at the same time. This will cause a spongy pedal and low pressure.


Posted Image

I think the simple and cleanest option is to relocate the distribution block out of sight. You can buy brass three way distribution blocks similar to the one on the diff if you only want to split the front brakes.

Edited by ls2lxhatch, 21 June 2009 - 12:54 PM.





0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users