Brake Issues --- Brainstorming please

[grego0o]

Hey all,

I'm finally at the end of this stage of the build and have driven the car home on the weekend, I have a V7 Spec C with Brembos

Brakes aren't feeling the greatest and need some feedback as to what everyone thinks may be the issue.

Problem:

Brake Pedal feels soft and sinks almost to the floor when applying brakes, brakes still work though but not the greatest.

Pedal is hard when engine is off, but returns to soft when engine is on.

Possible Problems I can list:

Air in the Brake Lines -- Have bled brakes (Brembos) inner and outer bleed nipples after i felt the soft pedal so this counts this out.

Air Line to Booster is blocked --- this would cause the brakes to be hard though?

Brake Booster is farked -- not sure of symptons of this as I have never had this happen before?

Maybe ABS is causing issues -- ABS is not lit up on the dash though? Haven't tried stomping on the brakes to see if it's still working either.

Any other ideas?

Any help is appreciated

Grego0o

[DRFVDR]

Needs bleeding,I still think this is the issue.. Soft when engine running would be the air in the system, hard when engine off is because u don't have the vacuum helping..

How did u bleed them, sometimes it has to be done oldskool,have some one in the car press brake to floor, then u open bleeder,let pressure and air out the close the bleeder, repeat a few times at each wheel.

[grego0o]

 DRFVDR said:

Needs bleeding,I still think this is the issue.. Soft when engine running would be the air in the system, hard when engine off is because u don't have the vacuum helping..

How did u bleed them, sometimes it has to be done oldskool,have some one in the car press brake to floor, then u open bleeder,let pressure and air out the close the bleeder, repeat a few times at each wheel.

Bled them with person in car, but rather than pumping brakes and releasing pressure while foot down I just opened valve and pumped brakes to push out air and fluid... could try the other way to see if it pushes any air out.

[Guest]

you did put the left caliper on the left side and right caliper on the right side aye? (bleed nipples at top if correct)

New or old pads?

Any play in the hub bearings?

[grego0o]

 Ichi Ban said:

you did put the left caliper on the left side and right caliper on the right side aye? (bleed nipples at top if correct)

New or old pads?

Any play in the hub bearings?

lololol yes the brakes are stock and are on the correct sides

Pads have been in the for 2 trackdays 5000ks of driving so not new but still have a little left on them.

No play in the Hub Bearings from what I know?

[Guest]

check all pads for uneven wear

Ie - taper wear , very common to give this exact fault

[grego0o]

 Ichi Ban said:

check all pads for uneven wear

Ie - taper wear , very common to give this exact fault

Will do, thank you sir.

[EJ20T]

are you sure the master cyl isnt creeping?

[Timmah]

Sounds exactly what I'm experiencing as well. And it's no different after getting 4 pots on the front as well ???

[Guest]

rear pads taper badly too, giving poor pedal when moving

[Timmah]

 Ichi Ban said:

rear pads taper badly too, giving poor pedal when moving

Will give them an inspection, cheers!

[boon]

I have a master cylinder for a V7 STi sitting around if you need one.

I had crazy bad intermittent pedal-to-floor action going on, turned out it was a shagged wheel bearing on the front left.

Did you change some lines around? Just to make sure, check that you've still got the restrictor pill in the vacuum line that goes from the manifold to the metal lines across the firewall, and make sure it's the right way around. Although I'm not sure if this would cause other problems.

Besides all that, re-bleed?

[grego0o]

 boon said:

I have a master cylinder for a V7 STi sitting around if you need one.

I had crazy bad intermittent pedal-to-floor action going on, turned out it was a shagged wheel bearing on the front left.

Did you change some lines around? Just to make sure, check that you've still got the restrictor pill in the vacuum line that goes from the manifold to the metal lines across the firewall, and make sure it's the right way around. Although I'm not sure if this would cause other problems.

Besides all that, re-bleed?

Hey man,

I've grabbed a spare booster from funky last night just in case i need it,

The lines have changed round in the engine bay but I have the resrictor valve on the right way!

Yeah looks lke I'll rebleed and then check brakepads and wheel bearings...

[igkgunn]

I'd look at the master cylinder as well as bleeding with person on brake pedal. Rebuild kits are pretty cheap from BNT and it's a pretty simple process.

[Scoobydoo]

 igkgunn said:

I'd look at the master cylinder as well as bleeding with person on brake pedal. Rebuild kits are pretty cheap from BNT and it's a pretty simple process.

For Brembos? They'd be a few hundy at least

[Guest]

 igkgunn said:

I'd look at the master cylinder as well as bleeding with person on brake pedal. Rebuild kits are pretty cheap from BNT and it's a pretty simple process.

best to leave this sort of work to experts

Seen two in the last year where guys thought they could rekit there own master cylinder and pinched a seal causing them issues

Master cylinders in general dont give any problems !

[EJ20T]

yes if you have no or limited experiance with brakes i wouldnt recommend doing your own master cyl rebuild. when doing any bleeding you havnt by any chance let the brake fluid run out? you may have to bleed the master cyl

[boon]

Just gonna throw it out there, but it's not that big f*ck-off turbo sitting there boiling the brake cylinder? Or does it do it dead-cold?

EDIT: And get yourself a brake-cylinder stopper ASAP. Cusco ones are cheap enough new from the Cusco importers in Auckland and they seriously improve the brake feel when you apply the jandle heavily.

[deathz0r]

Are there two nipples on the rears? Cos we only did one on each side (on the rears), Greg.

[boon]

Pretty sure there's 2 on the rears. And if you've had the system significantly empty and didn't bleed them then it will be full of air. Re-bleed! With someone on the brake pedal.

[funkytown]

the rears have two.

[DRFVDR]

And there u go sorted .com

I would rebleed the whole system using the way i suggested earlier

[deathz0r]

Yeah get your shit together Greg... farrrrrrrrrrr

[DRFVDR]

Man dont you hate when u cant get help