Brake pedal travel after brake upgrade!

[Stevie C]

Ok, have finally got round to upgrading/ fitting brakes on my A3 8P 2.0TDI Sport. I have fitted MK5 Golf GTI Calipers with 312 discs front and 286 (i think) on the rear and although there is a massive improvement in braking (fronts were bedded in over 200miles rears only went on yesterday) i seem to have far more travel in the brake pedal than what i did before which is taking some getting used to.

Is there anyway of rectifying this? like should i be upgrading something else in the braking system to cope with bigger discs?

Any help would be very useful!

 

[julians]

You need to change your brake master cylinder to match the larger piston area of the new calipers.

I'm not too up on the specifics of VAG brake parts, so I cant tell you for certain what master cylinder would be suitable, but I would imagine the one that is used on the GTI that goes with the calipers and disks would be a perfect match.

 

[Stevie C]

thanks, i thought i may well be something like that but wasnt sure. Anyone know if the MK5 Golf Master Cylinder will be a direct and easy replacement? Also anyone any idea of part number from ETKA and rough cost?

 

[Beddie]

The calipers as fitted to the 140TDi with 288mm discs as standard are identical to the ones fitted to a MK5 GTi so no need at all to change the master cylinder...
More than likely just air in the system, vag-com is required to do a full air-bleed correctly as it cycles the ABS pump in a particular sequence iirc
HTH

 

[Mikey]

as beddie says all you need is new carriers for the 312's not calipers, and new discs. bleeding can be a PITA, been there before.

 

[Khufu]

been there too, didnt realise there was a bleed nipple on side of the master cylinder on my old A3!

 

[julians]

oh yeah, improper bleeding would cause a long pedal for sure , I kind of assumed that they had been fitted correctly in my previous post about the master cylinder.

 

[Stevie C]

Guys, thanks for all the info. I will get it hooked up to VAG COM on Wednesday and ensure that they are bled through correctly too.

I didnt know there was a bleed nipple on the Master Cylinder either!!! :-(

 

[Stevie C]

Beddie! what do i need to do with VAG COM???

 

[Khufu]

you probably wont need vagcom. If air gets into the ABS pump you need to cycle it using vagcom to bleed the air out. This is really only needed if you have new ABS pump as you wouldnt introduce air into the pump unless the ABS came on when low on fluid (REALLY LOW!). My money is on the 8mm bleed nipple on the master cylinder if this currrent model still has it. (does the brakes pump up great with engine off?)

 

[Stevie C]

When moving if you pump the pedal twice, the second time you stop on a sixpence!!! massive difference over standard set up!

 

[Stevie C]

here are a few pics of the set up, more on anothere thread!!!

 

[Stevie C]

Thanks for the help guys, the 8mm bleed nipple on the master cylinder was the culprit, All sorted now and brakes feel amazing compared to standard.