GQ - What is this part? what does it do?

Joined: 26 Apr 2005 Location: Newy

Hi guys,

i was under my patrol today - setting up my gas system, and i noticed this large spring - attached to a bracket off my rear diff.

the other end of the spring is attached to a cylinder that looks like a brake propertioning valve or something simmilar

this is a 94 model RX petrol, im pretty sure my last patrol, a 89 model st didnt have this.

Can anyone confirm what this is and how it works? also one of the lines appear to have been crushed at some point - car seems to break fine so i am a little unsure of what is going on....

here are the pics

Any info would be greatly appreciated

Cheers
Stew

Joined: 20 Mar 2008 Location: Aus

i belive its the rear swaybar disconnect correct me if im wrong..

Joined: 27 Aug 2004 Location: sydney

brake proportioning adjuster.

More weight on the body will adjust the brake bias to the rear.

Joined: 04 Jun 2005 Location: Melbourne

Pretty sure it is the Brake proportining valve, That spring is supposed to be horizontal, So as you lift your vehicles height the bracket should be extended to bring it back horizontal, In the event of a heavy load it applies more rear brake, I Think??

Joined: 26 Apr 2005 Location: Newy

ok guys,

that makes sense - i was tryin to figure out what the spring was achieveing, didnt think about different load when towing changing ride height.

So is this on all gq patrols or just some models?

im assuming then that one line being crimped must be reducing my braking performance (mind you it performed flawlessly towing an unbraked car trailer (with car on it) yesterday).

Thanks for the info
Stew

Joined: 27 Jul 2005 Location: Adelaide - Australia

Brake Load Sensing Valve Spring doesn't hafta be horizontal, does hafta be 207mm (8.15")long top end of one hook to the top end of the other hook with a driver in the vehicle and no other load! Max length under max load should be 220mm (8.66") and with those lengths there is a pressure range between the master cylinder and the rear brake pressures that the pressures should be between. You need to be able to measure the pressure differential between the master cylinder and rear brakes to do this, and that takes one of those brake pressure balance guage jobbies, but for most purposes, all you really need to do is get the spring length correct!

Except for yours toy77! I'd guess that with your brake line crimped like that you need to get the line uncrimped and/or replaced and the brake balancing done properly, once you've got the spring length correct!

Cheers!

Joined: 27 Aug 2004 Location: sydney

toy77 wrote:

ok guys,

t

im assuming then that one line being crimped must be reducing my braking performance (mind you it performed flawlessly towing an unbraked car trailer (with car on it) yesterday).

Thanks for the info
Stew

If it aint broke dont fix it. doesnt look to crimped, just badly bent.

Joined: 14 Feb 2005 Location: Kilsyth, Victoria

so on my 2" spring and 1.5" body lifted shorty i would need to modify this to get my back brakes working harder? it seems my fronts lock up very quickly and the backs don't really do alot. i'll measure the spring tomorrow and see what i can work out Smile

Joined: 02 Dec 2007 Location: Brisbane

Whatever suspension lift you have you need to lift the bracket on the diff the same eg 4 inch lift means lift the bracket 4 inchs.
That will retain factory braking.
Theirs nothing technical in it . Very Happy

Joined: 14 Feb 2005 Location: Kilsyth, Victoria

would the lift cause there to be less braking pressure portioned to the rears? or do i have other problems?

Joined: 20 Mar 2008 Location: Aus

hmm i broke a bolt off mine is it going to affect anything?

Joined: 05 Mar 2007 Location: On board the Mothership

I usually tie mine off shut if in steep stuff..... makes for better brakes when going backwards !!