Cayenne ABS Bleeding

[andyg0141]

Hi All. Im having trouble getting the brakes bled on my 2012 Cayenne. It feels like air stuck in the ABS (pedal hard with engine off, with engine running you can get the pedal hard by pumping it but then it slowly drops to the floor).

Bought a Launch diagnostic tool that allows you to bleed the ABS but still the same. Not sure if its to do with US vs UK spec maybe (master cylinder on different side so different bleed sequence)?

Anyone able to offer any advice / thoughts? Thankfully have a 2 poster that its on so easy enough to potter away on.

Thanks in advance! Andy

[The Wookie]

Have you drained the system or done anything to introduce any air? If not then it sounds like a leggy master cylinder.

They can blow by under servo assisted pressure before they go spongey with the engine off

[andyg0141]

Yeah - I had the calipers painted and the pressure bleeder ran dry introducing air in to the system unfortunately!! Due to this, fairly sure it will be air in the ABS system?

[The Wookie]

Ah yeah that’ll do it!! I think it’s doable with a typical VAGCOM cable

If it’s anything like the BMW process then make sure you’ve got plenty of fluid to hand!!

ETA Sorry just read you’ve already tried it. Chances are you’ve still got air trapped in the master cylinder. They are a pain to bleed on the car. Perhaps try back bleeding them, I.e forcing fluid the wrong way back to the reservoir

[andyg0141]

Yeah - pretty certain it is just air trapped in the system as you say. Will keep trying and take it from there. Bit of a nuisance there being 2 bleed screws on each caliper needing bled too....!

[NMNeil]

An old trick for stubborn brake bleeding.
Set up the bleeding equipment as normal, hose, jar etc. then get a helper.
Starting with the wheel furthest away from the driver have the helper pump hell out of the pedal and then hold it down as hard as he/she can. Open the bleed nipple. Fluid, air and any other crap in the system will be forced out under high pressure. While the helper is still holding the pedal down, which should be on the floor now, tighten the nipple.
Check the level in the master cylinder then repeat with the next wheel.