Editing Bleed the brakes (section)

=== Bleeding front callipers===
==== S1 and non-ABS S2 ====

For the front brakes there are two ways to get rid of the small amount of air in the hose once it is re-connected to the car.

On an S1 and older S2 without ABS you can pump the brake pedal until the pistons come out (as if the pads where worn), attention DO NOT push them to much and get them out of the calipers!

Now open the bleeding nipple and compress the pistons with the flexible hose first while rotating and gently tapping the caliper in order to guide any air bubbles towards the other piston with the bleeding nipple. Push the piston in completely.

Now push the other piston with the bleeding nipple fully in. 
This will force any air bubbles out.

Now put the calipers and pads back in place and bleed once more.

Test for pedal firmness.

If this worked then continue with the next caliper.

==== ABS equipped S2 or spongy pedal ====

On more recent cars with ABS, or if you still can't get a firm pedal after the first try then there's still air in this circuit somewhere and you need to bleed it the traditional way.

The approach here is a bit cumbersome because of the design of the callipers that trap air in the inner piston.

If this is the case then the approach is as follows:

- Pressurise the brake bleeder with a low (8 psi) pressure to stop fluid and air traveling upwards to the master cylinder

- Tap on the calliper and hose gently with a plastic hammer to dislodge any bubbles that adhere to the surface 

- Remove a front calliper from the upright (2 allen head bolts), invert it so the connectng pipe is at the top and open the bleed nipple

- Tap the brake hoses gently and also tap on the inside of the calliper.

- Then (with your hands) squeeze the INNER piston in. This will empty the inner piston and force the bubbles to the front one. Make sure you push it completely in.

- Now carefully rotate the calliper normal side up again so the bleed nipple is at the top. Try to turn it so any bubbles in the outer piston will not try to go up the connecting pipe again.

- With the calliper 'right side up', tap the calliper again and squeeze the OUTER piston back into the calliper and watch for air bubbles escaping 

- Close nipple

- Lightly bolt calliper back onto upright

- Refit pads

- Test for firm pedal after some pedal pumping to seat the pads

- If succesful then tighten calliper bolts