Hissing brakes

[car.crash]

My rear bias valve hisses when I depress the brake pedal when driving. It doesn't do it when I'm stationary with the engine running. Any ideas on what's going on?

[J$£5GTT]

not sure what that could be,bias not leaking at all?,your brakes are fine otherwise?
how do you know its the bias?
:)

[car.crash]

No fluid loss, no air in system and brakes work fine. You can hear the valve hissing and I have no interior.

[Brigsy]

Are you sure its not the servo hissing?

[Gttnutter]

Weird why it only does slowing down at greater speeds. It does sound from the rear. It's as if the pad is taking of the surface rust..that's the kind of sound I was hearing.

[car.crash]

Are you sure its not the servo hissing?

100% from the rear of the car. I've read the valves can hiss as fluid exchanges but never heard it on a Gtt before.

[car.crash]

I've also swapped the bias valve and it's off my old car and never did it on that. Also if I'm above 3.5k revs and left foot brake the pedal is high and stiff but below that the pedal is low and soft. I've pretty much swapped every component but non of it was for new parts so can't guarantee fully working.

[fishead]

I've also swapped the bias valve and it's off my old car and never did it on that. Also if I'm above 3.5k revs and left foot brake the pedal is high and stiff but below that the pedal is low and soft. I've pretty much swapped every component but non of it was for new parts so can't guarantee fully working.


if theres not a lot of vacuum in the manifold there will be not a lot of help from the servo

[car.crash]

that would make sense on the pedal issue, any ideas on the hissing tony?

[fishead]

no mate not really, are you 100% its the bias ?

could try unspringing the lever an tieing it back so no brake effort to the rear, does it still do it.

could try removing rubber boot, does it still do it

how have you bled the brakes ? ive had all sorts of trouble with rears on a couple of cars. trapped air thats jus being pushed sucked about an not actually going anywhere ?

[car.crash]

new discs and pads are on all round and all bedded in, brakes have been bleed countless times and the car stops very well and pretty well balanced after much adjusting. at high revs when i touch the pedal even slightly i can hear it hiss and the pedal is also higher, at low revs its quiet and the pedal is softer. the rear discs are drilled but surely it wouldnt be that and it deffo souns like its coming from middle of boot floor.

[modfather]

could it be the brake compensator

[jesus in the seat of a 5]

despite laughing at logs post id say it may be the servo.....:scratch:

[fishead]

how did you bleed them, leg power, sucker bleeder, pressure bleed ?
are the rear pads new fandango fancy things made of noisy stuff ?

by the looks of it rich has heard it ? best thing i recon get him round again, tie him to a skate board, bunjee him to the floor pan an drive around untill he is 100% where its coming from.
prob best to keep it below a ton as ive seen some proper tank slapping speed wobbles on skate boards, be funny as **** seeing a human [term used loosly as we talking about richy] torpedo lauch out the side of an r5 on a roundabout

[car.crash]

I did swap the servo a few years back but it was a used part. It holds vacum and the one way valve on the engine and servo is also new.

[rs250nut]

how did you bleed them, leg power, sucker bleeder, pressure bleed ?
are the rear pads new fandango fancy things made of noisy stuff ?

by the looks of it rich has heard it ? best thing i recon get him round again, tie him to a skate board, bunjee him to the floor pan an drive around untill he is 100% where its coming from.
prob best to keep it below a ton as ive seen some proper tank slapping speed wobbles on skate boards, be funny as **** seeing a human [term used loosly as we talking about richy] torpedo lauch out the side of an r5 on a roundabout


Nutter, im going to start calling you danger mouse:laugh:

[car.crash]

I bled them with a pressure bleeder. Lost count of how many times but they are sharp. Front pads are ds2500 and rears are Renault ones. It was front heavy on the brakes but a quick tweak and it feels very balanced but the noise remains the same. No interior is in the car so im fairly sure it's the bias valve.

[modfather]

I bled them with a pressure bleeder. Lost count of how many times but they are sharp. Front pads are ds2500 and rears are Renault ones. It was front heavy on the brakes but a quick tweak and it feels very balanced but the noise remains the same. No interior is in the car so im fairly sure it's the bias valve.


im sure i got 1 round here if you need 1