markyboywrx

iTrader: (4)

Evening...
Classic sti v3
Having an annoying brake issue.....
Hit the pedal no pressure, hit it a second time they work spot on..
Bleed the system, totally refurb the calipers at the front everything replaced...
Pedal now is low when pressed and crap still ,
but on 2nd press of brake within seconds of first pres they work fine?!???

Really am annoyed and lost with this issue

stonejedi

iTrader: (51)

Sounds like you still could have air in your system,lines etc...failing that it could be a problem with your brake master cylinder,worn brake pads it could be quit few things you have to work through the whole of your brake system systematically to track down the problem but i would bleed them again and make sure it's done properly and there is no chance of air in the system first.SJ.

Godspeed Brakes

iTrader: (259)

Have you fitted the calipers back on the right sides so the bleed nipples are at the top of the caliper and not at the bottom ?
If so then it would like they need bleeding again

markyboywrx

iTrader: (4)

Hello,
Yes mate, identical problem to I had before, replaced brake lines also, bleed system too!

MichaelW

iTrader: (7)

It sounds like the master cylinder could be faulty.

markyboywrx

iTrader: (4)

That's where my head points too.... Is that a pain to replace?

MichaelW

iTrader: (7)

No they are straight forward enough to change. You will then need to bleed all the brakes again afterwards.

markyboywrx

iTrader: (4)

Is it inside under the dash and aalso the engine bay?

MichaelW

iTrader: (7)

It's in the engine bay, bolted to the brave servo. Two nuts and a few brake pipes and it's off. Fit the new one in reverse and bleed all the brakes starting with the n/s rear (furthest away).

markyboywrx

iTrader: (4)

Thanks, any idea where the bolts are?.. Iv got a newage one here il stick in

MichaelW

iTrader: (7)

You can't miss them. Lift the bonnet and look at the brake servo and the cylinder is mounted to it. You can just see one of the nuts in the attached picture in the top left.

markyboywrx

iTrader: (4)

Ok will the back large Round piece stay located or that wi'll come off with those bolts?

MichaelW

iTrader: (7)

The large black round piece is the brake servo. That stays where it is and it is bolted from under the dash. You just need to remove the two nuts, disconnect all the brake pipes to the master cylinder and pull it all towards the front of the car.

MichaelW

iTrader: (7)

You will need to unplug the fluid level sensor as well.

markyboywrx

iTrader: (4)

You think that the servo will nit be at fault?

MichaelW

iTrader: (7)

Very doubtful. Usually servos will leak air which you can hear, makes the car run lumpy and will cause a hard brake pedal that won't stop the car. If your pedal is dropping to the floor then the chances are you've either got a damaged seal in the master cylinder or one of the seals has flipped round.

riiidaa

iTrader: (2)

what are you using to provide pressure when bleeding?

markyboywrx

iTrader: (4)

Another person :-)

stonejedi

iTrader: (51)

SJ.

markyboywrx

iTrader: (4)

Right, iv now bled the brakes, changed The master cylinder, and still have an issue!!!!!
There better but not how they should be that's for sure .

Also now iv changed the master cylinder I hAbe Tue handbrake light on permanently......

DannyBoy007

iTrader: (7)

You did bleed the rears? and you did bleed them in the correct order?

markyboywrx

iTrader: (4)

Yes bled all four, started with
rear left
Rear right
Front left
Front right

Godspeed Brakes

iTrader: (259)

As you have had the calipers off to recondition them did you fit them on the right side So the bleed nipple is at the top of the caliper ? You can fit them on the wrong side with the nipple at the bottom and they will never bleed properly

I did mention it earlier in the thread but you didn't answer

markyboywrx

iTrader: (4)

Sorry yes both at the tops

Godspeed Brakes

iTrader: (259)

Does the pedal drop after you have driven it a short while , or does it do it standing still ? A wheel bearing can give you this problem

markyboywrx

iTrader: (4)

When still pedal is still quite low, ideling however if you dab/push the break let off and back on in a faily quick concession there perfect, same when driving, dab the brakes low pedal, on/off the pedal there perfect..... It's like it's needs that first prime - press before they will work?...

markyboywrx

iTrader: (4)

Iv used your stainless pistons, New casting seals, top seals etc etc, the brakes work brilliant BUT on the 2nd press of pedal

Godspeed Brakes

iTrader: (259)

Check each wheel bearing for play , if there is some play it will cause the disc to float and push the pistons back into the calipers and will give you the problem you're getting

toby69

Aye ours was doing the same thing, I did suspect a wheel bearing was gone for sometime. Although not making the usual wheel bearing noises! We got the wheel bearing changed and the problem has gone

markyboywrx

iTrader: (4)

There is a brand new one on the passenger side so could only be drivers side, il have a look tomorow and check them