Audi Coupe 20V Brake Schematic

Inexperienced Joined: Jul 12, 2009 Posts: 44

Been trying to bleed the brakes and tried both manually and pressure bleeding [ from both ends !!] but the pedal is soft and nooooo brakes Sad

The connections at the Master cylinder are a bit weird with connection from front and back circuit going to a "4 port device" located underneath the Master cylinder and then the output from that going to the Brake bomb..... I think

The real problem is I am not sure what bits are what in the circuit and really need a Hydraulic Schematic..... I have searched net but its not coming up with a hydraulic schematic...........

Anybody help ?

Site Moderator Joined: Jan 31, 2003 Posts: 9144

forget the brake bomb - it's nothing to do with brake hydraulics.

the brake system has 4 calipers (slaves), a master cylinder, brake pressure regulator and the abs pump.

Typical order is

MC->BPR->ABS->calipers

order for bleeding

MC
BPR
left rear
right rear
left front
right front
MC

Inexperienced Joined: Jul 12, 2009 Posts: 44

just posted detailed reply and its got lost ??

Question how do you bleed the MC and BPR ?? ie what actually happens.......... which port, what action ?

thanks

Site Moderator Joined: Jan 31, 2003 Posts: 9144

Not all master cylinders have a bleed valve. if they don't, you can skip that step - same goes for the BPR.

If they have a bleed valve it will be obvious. You just open it and allow the pressure bleeder to push the fluid through - catch it in a spare container. I usually push about 250ml through on them.

If you fit a new MC and it has no bleed valve, you need to bench bleed it before fitting.

Typically, unless you are doing a complete fluid flush and replace, you can get away with bleeding only the calipers. 500ml per valve.

I also forgot about the clutch slave which shares the same reservoir. Do that first before doing the brakes