PDA

View Full Version : Gq Brake bias



Bloodyaussie
6th February 2015, 12:53 PM
I have had an issue with my brakes and has gone on for some time now.. it seems under heavy braking my rear brakes work more than the fronts and yesterday with a heavy load in the trailer I felt the brakes were not doing there job.

I have a brake bias bracket fitted and I measured it from eye to eye and it measured at 3 and a half inches and my car sits on a 4 inch lift?

Has anyone had this issue or does anyone know how to sort this.. I run good quality pads and discs.

The rear of my car sits higher than the front since fitting a diesel...

BillsGU
6th February 2015, 01:57 PM
I have just had a similar problem with my GU. The answer ended up being that the LPV was faulty. If it is not bled occasionally it accumulates moisture and corrodes the piston - which then sticks or whatever. My brakes were rubbish and are fine after the valve was replaced.

Bloodyaussie
6th February 2015, 02:01 PM
Thanks for that mate will look into it. .

I just went out to take a pic just incase iy was something stupid...lol

Plus some can only cope with pictures.

54872

happygu
6th February 2015, 05:23 PM
I have had an issue with my brakes and has gone on for some time now.. it seems under heavy braking my rear brakes work more than the fronts and yesterday with a heavy load in the trailer I felt the brakes were not doing there job.

I have a brake bias bracket fitted and I measured it from eye to eye and it measured at 3 and a half inches and my car sits on a 4 inch lift?

Has anyone had this issue or does anyone know how to sort this.. I run good quality pads and discs.

The rear of my car sits higher than the front since fitting a diesel...


BA,

It won't be the height of the extension bracket, as they don't even put one on for a two inch lift ..... yours is only 1/2 an inch from standard ....

The only thing to look at would be the adjustment side of things - to set it up a little better for you.

When you load up the back, it drops, releasing pressure off the spring, and giving you more rear brake power.

You can adjust it so there is more pressure on the spring, giving you less rear brakes.

Mic

doka404
6th February 2015, 06:11 PM
One more thing to check if its not the LPV....A while ago i rebuilt my GQ brakes (was actually upgrading to the twin spot EFI Fronts) and before I started the job everything was pretty well balanced.
I rebuilt the rears first while waiting for parts for the fronts, and after that, the rears over powered the fronts. Once the fronts got sorted everything went back into balance..

Maybe the front slide pins have siezed up a bit and the rears are actually working better than the fronts..or something like that..just another thought..

billyj
7th February 2015, 08:06 PM
get your front calipers reco'd my patrol was doing similar and while they looked to be working( would stop a spinning wheel while jacked up) they were actually siezed and doing stuff all. other thought is maybe some air in the front lines, the twin piston fronts are a complete bitch to get bled properly

Stropp
8th February 2015, 03:03 AM
Yes it pays to pull the fronts off and clean the pins and check that the calipers are actually working as I know when I got mine I had to install new pads and everything was seized up.

Bloodyaussie
8th February 2015, 08:29 AM
The fronts were rebuilt not that long ago.

This has really only be noticeable after going to 4 inch lift.

I was looking at the valve at the back and the spring has tension on it with about 1cm already pushing on the piston.

Is there supposed to be any tension on it while it sits idle?

BigRAWesty
8th February 2015, 09:01 AM
Could it be pure coincidence that the valve has seized and having the 4" lift has just made the braking feeling more noticeable?

bigkevlittletruck
8th February 2015, 11:09 AM
When you raise a car you should adjust the brake bias length as well . Try disconnect tie it up like your loaded up and test brakes.

BillsGU
8th February 2015, 11:16 AM
If you look at the GU repair manual under the "Brakes" section (BR) it gives you a diagram of the valve and lever and a table which tells you distances between certain points as a means for adjustment.

Parksy
8th February 2015, 02:17 PM
I rebuilt my brakes not long ago and found the grease had dried out and gone stiff. Worth a check Jonathan, just in case.

billyj
8th February 2015, 08:04 PM
the 4 inch lift would have ment new brake lines front and rear yes? i bet you still have some air in the fronts. took me farkin ages to get all the air out when i reco'd my calipers and changed the lines

Parksy
8th February 2015, 08:38 PM
Yes the fronts are a nightmare to bleed. Regular bleeding didn't work, so I tried gravity bleeding and it did the trick. Solid brake pedal. Dead easy as well. Hook a hose up to the bleeder and crack it open. Have the brake reservoir open, so the fluid will flow and can be topped up. 20 mins per wheel, just dripping away into a bucket. Worth a shot and very little effort.

Winnie
8th February 2015, 08:48 PM
Funny you post this now as today me and a mate were driving down into Walhalla, I was towing the camper and when we got into Walhalla both our GQ's had smoke coming from the rear left brakes

Bloodyaussie
9th February 2015, 07:51 AM
Funny you post this now as today me and a mate were driving down into Walhalla, I was towing the camper and when we got into Walhalla both our GQ's had smoke coming from the rear left brakes

As was the same with me coming into Captains Flat.....?

I have not had a chance to look at it yet as I spent the weekend shooting and the rest trying to be the perfect husband and dad.

The brakes were bled at the workshop by Georges brother and I can tell you they were done properly.

The lines went in before I went to 4 inch lift.

Winnie
9th February 2015, 07:56 AM
I have just not long ago put all new discs and pads too

Winnie
9th February 2015, 08:22 AM
As was the same with me coming into Captains Flat.....?

Mine did then as well

Bloodyaussie
10th February 2015, 08:08 AM
Was having a read and the distance on the spring with the brake depressed should be 220mm long, I have not had a chance to check this as yet as I do not want to start the car just so I can check the brakes.. This is a starting point anyway.

It does not mention in the manual that I could see about the plunger being depressed at all?

Winnie
10th February 2015, 09:00 AM
I'll check mine at home tonight

alfonso
7th April 2015, 09:21 PM
In my opinion the more tension on the spring the more braking to the rear . the spring in the photo looks tight . Is the arm coming off the adjustment screw as far as possible from the end re can not move any closer to the spring. if so then the rear brakes have full power which could be causing them to lock . Forget about the spring length and adjust the tension via the elongated hole in bracket connected to the diff try it in the middle of the adjusting pin do not turn pin as this is factory set. Is your vehicle loaded or unloaded if unloaded or light the arm may need to be closer to the end of the adjusting screw. When I did my ute I placed a jack under tow ball and lifted weight off the axle the spring depressed meaning less breaking needed as less weight when lowered the spring tightened meaning more weight which would require more rear braking just a thought .

Winnie
7th April 2015, 09:27 PM
Have you sorted this out Jonathan? I want to upgrade to EFI front calipers and will rebuild them all when I find some. I think my front brakes are just not working very well

alfonso
7th April 2015, 09:44 PM
Hey Winnie it could be that your rear brakes are working too well . Try adjusting brake bias first as per my last post then you will feel more from your front brakes hopefully

Winnie
7th April 2015, 10:11 PM
Hey Winnie it could be that your rear brakes are working too well . Try adjusting brake bias first as per my last post then you will feel more from your front brakes hopefully

I will have to re read that while looking at it, but thanks for that