Brakes Problem

[Rayala]

It is a Patrol thing. Because the booster on them is so big and effective, it gives the symptoms of a bypassing master cylinder.

[BillsGU]

I had the same symtoms as you have and had it to many mechanics (and brake specialists) to fix with no improvement. I heard about the LPV problem and bled it myself. A whole lot of brown muck came out of it. The brakes did improve a bit so I took the valve off the Patrol and when I had a close look at it I noticed it was partially stuck. I went to a wrecker and picked up one off a recent Patrol, fitted it and the brakes are now good as new.

[10G]

I had the same symtoms as you have and had it to many mechanics (and brake specialists) to fix with no improvement. I heard about the LPV problem and bled it myself. A whole lot of brown muck came out of it. The brakes did improve a bit so I took the valve off the Patrol and when I had a close look at it I noticed it was partially stuck. I went to a wrecker and picked up one off a recent Patrol, fitted it and the brakes are now good as new.

What year is your GU Bill??

[Throbbinhood]

Small hijack, but is there a '2nd stage' to the pedal? Ie, when I depress the pedal far enough under extreme heavy braking, does the pedal get to a point and then hit another rod or something to increase braking pressure? Or is it all in my head.

[dom14]

Small hijack, but is there a '2nd stage' to the pedal? Ie, when I depress the pedal far enough under extreme heavy braking, does the pedal get to a point and then hit another rod or something to increase braking pressure? Or is it all in my head.

There's only one rod on the master pump. May be you're feeling the LPV kicking in??!!

[Throbbinhood]

There's only one rod on the master pump. May be you're feeling the LPV kicking in??!!

Quite possibly. All I know is I can feel some sort of feedback in the pedal and then the thing just stops haha!

Hey mudski I think it was you, you were mentioning the pedal slowly going down, how do you find it on long steep downhills, say out in the high country? Ever run out of vacuum and subsequently out of brakes?

[Turtle_au]

LPV will give the feeling of 2 stages under heavy braking.
Initial braking causes weight transfer to front, LPV senses this and reduces pressure and fluid to rear brakes.
As you slow down more weight transfers back to the rear and the LPV will then start increasing the pressure and fluid to rear brakes.

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[BillsGU]

What year is your GU Bill??

It is a 2000 GUII.

[Col.T]

G'day 10G man.
Seems to me, a brake system is fairly simple.
Bang your foot down,,,master cylinder shoves pressure down the tube,,,,,,
slave cylinder slams pressure into the pads. All 4 wheels.
You've got a few points at which there could be a weakness/leak/failure.
4 wheel acting points. Got leakage???
The balancing point at the ars*nd of the system?? I've never seen leakage there but?.
I think (although I'm usually wrong), that if there's visibly no leak at any of those points, the only problem can only be the master cylinder with some bypass system involved.
Can't remember how those bypass/safetypass/whatthehellpass systems work but if , as said, there's no leak elsewhere I'd be looking for a new master cylinder.
Good luck,
Col.

[billyj]

keep bleeding, when i did new master, lines and reco calipers on my gq it must have taken about 3 litres of fluid before all the damn bubbles were out and i had a good solid pedal