soft/low brake pedal

[pete30nz]

Evening men,

I've had some progress today. In the last few days I've bled the brakes twice and test drove the car just earlier this evening.
The pedal is higher, and it's a little spongy.
In saying this during test driving, working the brakes and getting the ABS to kick in 98% of the time. When I inspected for leaks at home after the drive, I found a single brake fluid dribble down the booster.
So I'll rekit it with new seals and it should be good to go again.

I also tested for vacumm at the booster valve with and with out engine running, and it had vacumm both times.

Cheers Pete

 

[pete30nz]

So you have VT front calipers? My VR never felt good with them running a VR master. VT-VX master should change feel.

Evening, no I still have VR/VS calipers.

 

[vc commodore]

Evening men,

I've had some progress today. In the last few days I've bled the brakes twice and test drove the car just earlier this evening.
The pedal is higher, and it's a little spongy.
In saying this during test driving, working the brakes and getting the ABS to kick in 98% of the time. When I inspected for leaks at home after the drive, I found a single brake fluid dribble down the booster.
So I'll rekit it with new seals and it should be good to go again.

I also tested for vacumm at the booster valve with and with out engine running, and it had vacumm both times.

Cheers Pete

Good chance, once the master cylinder is rekitted so you don't have leaks, the pedal feel should be spot on, with no spongeness

 

[pete30nz]

Good chance, once the master cylinder is rekitted so you don't have leaks, the pedal feel should be spot on, with no spongeness

I know I can do the internal pistons seals my self, is this all that you would say needs doing internally.

Pete

 

[vc commodore]

I know I can do the internal pistons seals my self, is this all that you would say needs doing internally.

Pete

Generally yes....Just make sure there is no pitting and 99% of the time, putting new seals through solve the problem...

 

[pete30nz]

Hi fellors,

I'm getting a full seal kit for the master this week, and will fit it a.s.a.p

Fingers crossed

Cheers
Pete

 

[Vin999]

Evening, no I still have VR/VS calipers.

You still have VR?VS calipers and you put on a VS booster and the larger bore VX master cylinder which now leaks ??
Why didn't you just put the VS m/cylinder to match the VS booster and calipers ??

 

[pete30nz]

Morning,

VS booster better than VR booster, as the VR boosters I'd tried were making the wooosh / hiss's sound when pushing pedal. Standard calipers at moment, and yes VX 1 inch bore master cylinder.
Because the VR master and booster wasn't working out.

This was suggested by more than one person.

Master leaking due to use I'd say.
New master seal kit should make no leaks, unless the bore is pitted, which will let through fluid past the seals.

Will update when new seals installed

Cheers
Pete

 

[Vin999]

Morning,

VS booster better than VR booster, as the VR boosters I'd tried were making the wooosh / hiss's sound when pushing pedal. Standard calipers at moment, and yes VX 1 inch bore master cylinder.
Because the VR master and booster wasn't working out.

This was suggested by more than one person.

Master leaking due to use I'd say.
New master seal kit should make no leaks, unless the bore is pitted, which will let through fluid past the seals.

Will update when new seals installed

Cheers
Pete

Ah I see why? you’re having issues, your using old second hand worn out components and mixing incorrect compactable parts hence why you’re having so much issues with leaks, air, abs and pedal movement with spongy feel. Suggestions would have been thinking you changing to the larger VT/VX disk rotor and 2 pot calliper for the VS booster and VT/VX master cylinder conversion you did, not just leave your smaller front disks/callipers on.

The VX m/cyl front bore is bigger than 1” with a fast fill capability to suit the larger VT/VX disk rotor area/pads with front 2 piston callipers and overkill/waste on your single piston callipers
The VS m/cyl front bore is 1” and suits the VR/VS front smaller disk rotor area/pads and piston callipers with a better pedal movement/feel.

It’s the sum of all the components that make up the whole brake system, why change on a simple standard car what the factory engineers made compatible/adequate for that model without issues.
Finish putting VT/VX front disks/callipers to suit your VS booster and VX m/cylinder and you will have a great compatible abs brake system

 

[Pollushon]

You still have VR?VS calipers and you put on a VS booster and the larger bore VX master cylinder which now leaks ??
Why didn't you just put the VS m/cylinder to match the VS booster and calipers ??

It defeats the whole purpose of the upgrade. This upgrade is primarily about improving the master cylinder which exerts the force. VS booster is just a better booster than the prior models and bolts straight in.

The caliper upgrade is nice but not mandatory, this mod predominantly leaves you with more pedal force and better modulation on single pot pinchers.

That sucks about the master mate. In 6 upgrades I've never experienced that, I swear normally this upgrade is a piece of piss with many rewards. Is it possible that master was sitting around empty for a long period?