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MK1 Audi TT 225 quattro brake bleeding
sonic - 27/3/18 at 07:42 PM

Hello all

Does anybody on here have any knowledge of how to bleed the above brake ? or even better know the bleeding procedure please

I have looked on Google which seems to have conflicting information

any help welcome

owelly - 27/3/18 at 08:58 PM

Check the master cylinder for bled screws and start there. I seem to remember there should be one for each circuit, so two. Then move to each wheel starting at the closest to the m/c. Some folks say start at the furthest away but that makes no sense to me.

sonic - 27/3/18 at 09:28 PM

thanks mate I will have a look

ian locostzx9rc2 - 27/3/18 at 09:32 PM

As above and have the engine running so the valves in the abs unit are open

Mr Whippy - 28/3/18 at 11:56 AM

quote:
Originally posted by ian locostzx9rc2
As above and have the engine running so the valves in the abs unit are open


they usually are always open. Bleeding brakes in ABS cars is just the same as non ABS ones, I wouldn't have the engine running as then you'll have the servo assist and it will just blast out, not required

It will be just the same old (this was what I was doing last night)

Start at the back, hose on the end in a jar half filled, open it and gently pump away till it the pedal firms up or air stops bubbling up. Best to have someone topping up the reservoir at the same time and checking bubble progress. I usually go round it twice. Very simple job.

[Edited on 28/3/18 by Mr Whippy]

ko_racer - 28/3/18 at 02:08 PM

As above, it's the same as any other car really.

There i a bleed nipple on the master cylinder from what I remember, as long as you don't empty the reservoir you shouldn't need to do this. You will know if the pedal is spongy it will need doing though,

I've seen people suggest not pushing the pedal down to far as it can damage the master cylinder seal, but I'm not sure on that myself.

If you had emptied the abs or got air in the system you might need to use VCDS or a dealer tool to activate the ABS pump, it's fairly straightforward if you need to as long as you have the tool & software.

For a general fluid change just pump it through as you would any other car.

sonic - 28/3/18 at 06:47 PM

Hi all

thanks for the replies so far

changed the rear driver side calliper, bled the brake as usual with engine off. got a good pedal pressure and thought job done. started the car and pedal went down almost to the floor, pumped pedal got pressure and it dropped off again.
re bled back calliper and no air came out.

every time I have bled brakes in the past and got good pressure never had a problem when started the car

any ideas ?

obfripper - 28/3/18 at 08:28 PM

The correct procedure is to prefill the caliper through the bleed nipple with the caliper placed at a specific orientation before connecting to the brake hose, it's a pita to do though.
Manual reference

An alternative that works just as well is to unbolt the caliper, use a mechanical windback tool to hold the piston in position, then tilt the caliper so the piston is pointing at 45° to horizontal with the bleed nipple at the highest point possible. Then bleed the caliper as normal, giving it an occasional tap to help dislodge any trapped air.
This should expel the air that is giving you a saggy pedal.

Dave

sonic - 28/3/18 at 08:40 PM

Hello and thank you for the information, I will give it a try

owelly - 28/3/18 at 10:20 PM

Don't forget the m/c bleeds......I changed on rear wheel cylinder on my Octavia and even though I was sure I hadn't lost much fluid, the m/c needed bleeding.

CosKev3 - 29/3/18 at 06:58 AM

Never had trouble myself, but reading posts on forums some people have had to use VAGCOM to activate the ABS pump to bleed properly.
But pretty sure these were when the system had been fully drained.