Brake bleeding on an Audi TT

[Shad]

Had a bit of trouble today changing the brake fluid on a friends Audi TT. Everything went well and the brake pedal became nice and firm with no more nasty stuff coming out of the nipples and no more air either. However, once the engine's running the brake pedal becomes verrrrrry long and it feels like (and sounds like) you're pushing air until it starts to bite right at the end. The bite at that point is great and the car stops well but it's not particularly safe being right at the floor.

Have tried re-bleeding several times, with and without the engine running just to be sure. Completely stumped at this point. Did wonder about the seals in the master cylinder but there's no pedal creep.

Any ideas?? Car currently stuck on the driveway!

[GoNz0]

better off going to a audi forum m8, you may find you naffed it up due to the ABS sucking air in, from what i know on my BMW your not ment to manaully bleed the brakes, but you should be able to get away with it.

the proper way is to hook it up to a machine that sets the ABS into fill mode and cycles the fluid through while hooked up to a feeder system.

was there a problem b4 u started ?

some info here, it says u may naff it up if u push the pedal all the way down, reccomends a chock to keep the pedal 2 inch from the bottom.

http://www.goapr.com/Audi/support/A4...n%20Manual.pdf

[Wh@l3fish]

Could be that you've got air trapped in the hoses somewhere. Could I ask what method you used to bleed the fluid?

[acidrainy]

Manually bleed my TT a couple weeks back after fitting calipers. I got the exact same thing. I got my dealer to put it on an autobleeder for me to solve it though. :/

[Shad]

Thank you chaps.

The initial problem was a long brake pedal (not as long as now though) and spongy-ness, and sure enough quite a bit of air came out during flushing/bleeding. We've had a block under the pedal and have been doing the usual bleed procedure of pump pedal, hold down, release nipple and tighten. Rinse and repeat.

One other suggestion I've had today is to try bleeding the master cylinder with the same method. Failing that we'll get it done at a local friendly VW specialist.

It's frustrating that modern cars are so over-complicated - this is a simple basic job, shame on you VW!

[GoNz0]

u could always go buy a pressure bleeding kit, there about £20 and normally hook up to the spare wheel.. watch the fluid levels tho !

[jon bda]

It's frustrating that modern cars are so over-complicated - this is a simple basic job, shame on you VW!

We had the truck garage from next door to us ask if we could bleed the brakes on a new Transit pickup a few weeks ago as they couldn't do it. It had had the rear axle replaced and needed plugging in to allow the abs pump to let the fluid through but our Snap-On gizmo wouldn't even touch it. Last seen going to the Ford stealership on a flatbed!.

[Konan555]

I take it you didn't let the header get anywhere near empty? Air in the ABS valve block is an utter sod to clear.

I had some enter mine and I swear it's still not clear after about 5L of new fluid being pumped through it. Not only that, it stuffed up the NRV for the rear circuit.

[Shad]

Nope the MC was constantly topped up. Car's booked in with Audi for them to do it properly.

Rubbish.

[badass]

Thank you chaps.

The initial problem was a long brake pedal (not as long as now though) and spongy-ness, and sure enough quite a bit of air came out during flushing/bleeding. We've had a block under the pedal and have been doing the usual bleed procedure of pump pedal, hold down, release nipple and tighten. Rinse and repeat.

One other suggestion I've had today is to try bleeding the master cylinder with the same method. Failing that we'll get it done at a local friendly VW specialist.

It's frustrating that modern cars are so over-complicated - this is a simple basic job, shame on you VW!

One question:

Do you know why the pedal was originally spongy?
Was the fluid ancient? Had the car missed about 3 years of servicing?
If not, bare in mind there could be a leak. Bleeding only cures the symptoms. Have a very close look at all of the brake pipes.
a few years ago my mum put a car in a garage because the brake pedal was spongy and the colplete halfwits at the garage observed the air in the braking system, but simply did not have the mental capacity to do their own jobs properly and wonder why there was air in the braking system.
And bare in mind that if the brakes suddenly fail, you've still got the gearbox and handbrake to slow down with. It might just save you an accident but that is no substitute for properly working brakes and takes about 3 times longer to stop.