URGENT HELP Lux w/ GQ rear diff, braking problems

[justinshere]

Hey

Ive just fitted a H260 to the rear of the lux. I was a drum brake diff which has been converted to discs using GQ calipers and rotors, so in theory its a GQ rear end.
Having problems with the brakes not braking. I have had the front and rear bleed so many time and no different.
I know alot of people put GQ is the rear of lux's so has anyone else had this problem?
When i put my foot on the pedal it will go right to the floor, fronts will almost lock up on the tar but the rears only just skim the rotors.


Bit of a run down of what i am running or have done-
- Using 80 series master cylinder... its been in there for about a year with no probems.
- The rear brake line is running straight out of the LSPV, so obviously im still using the LSPV
- Bar from the LSPV to the diff makes no difference whether is up or down
- Using a rear braided line.
- Using standard lux front diff
- New rear brake pads
- The rotors had surface rust but ive cleaned 80% of it off with a wire wheel.
- Ive swapped the rotors with others and no difference

I was thinkin that it could be that the GQ calipers are not getting enough fluid to fully push them and make contact with the rotors
I have a Strange Brake Proportioning Valve to fit, i will be removing the LSPV.

Any help appreciated
Cheers Justin

[-Nemesis-]

I was thinkin that it could be that the GQ calipers are not getting enough fluid to fully push them and make contact with the rotors

Without knowing the solution, I'm betting that is the problem. Sounds like the booster/MC can't provide enough pressure to the pistons up the back.

[coilylux]

Hey

Ive just fitted a H260 to the rear of the lux. I was a drum brake diff which has been converted to discs using GQ calipers and rotors, so in theory its a GQ rear end.
Having problems with the brakes not braking. I have had the front and rear bleed so many time and no different.
I know alot of people put GQ is the rear of lux's so has anyone else had this problem?
When i put my foot on the pedal it will go right to the floor, fronts will almost lock up on the tar but the rears only just skim the rotors.


Bit of a run down of what i am running or have done-
- Using 80 series master cylinder... its been in there for about a year with no probems.
- The rear brake line is running straight out of the LSPV, so obviously im still using the LSPV
- Bar from the LSPV to the diff makes no difference whether is up or down
- Using a rear braided line.
- Using standard lux front diff
- New rear brake pads
- The rotors had surface rust but ive cleaned 80% of it off with a wire wheel.
- Ive swapped the rotors with others and no difference

I was thinkin that it could be that the GQ calipers are not getting enough fluid to fully push them and make contact with the rotors
I have a Strange Brake Proportioning Valve to fit, i will be removing the LSPV.

Any help appreciated
Cheers Justin

i had the same prob when i put the GQ diff in mine....
am using a 80 series non ABS booster and master.

i bypassed the load valve at the back as it was the only way i could get a pedal...
but visually its still there and operational.

if your still stuck let me know and ill take pics on how i did it...

[simkell]

i would of said the brake proportioning valve, not letting enough pressure though to the calipers. if you can by pass the lspv and see if it makes a difference.

[justinshere]

Bit of an update, ive sorted this problem.
Removed the LSPV and still the same.
Where it was mounted was allowing an air pocket to stay in the top i moved that caliper to the back side of the rotor re bleed it, all sweet! I will still have to put an adj. prop valve in cos the rear it locking up before the front.

Thanks for the info tho fellas

[/i]