Upgrading the brake lines

I've put stainless steel flex lines in all of my cars; the Triumph has them as does the Carrera. In both cases the original rubber lines were ancient, and in both cases I was using the car in Auto-X competition and wanted to remove any squish in the brake pedal. It's a personal thing, but I am a huge fan of what they do. So now the A5 is 12 years old and hitting 97,000mi. I had to flush the brake fluid because its been over 2 years, and I figured I'd install the new lines at the same time.

The Audi's lines are all the same, the front are just a tiny bit longer. There is a bracket on the body where the hard line terminates, then there is a spring clip- kind of a lock washer for where the hoses join up. The flex line is not round, it fits into a slot in the bracket. It's a lot like the Beetle or the 911, only they use a clip that pulls out. This one stays in place.

Tools:

11mm crescent or brake wrench - hardline & bleed nipple

14mm brake wrench - to remove stock hose from caliper

13mm brake wrench - to install new Goodridge line into caliper

Power Bleeder - I used the one from Motiv. Just make sure you have the correct adapter for your master cylinder.

1 liter of DOT4 fluid. The VW certified stuff is actually very affordable. I've also used ATE.

The fronts are pretty easy, turn the steering wheel to the opposite side to give you better access. Undo the union to the hard pipe and then unscrew the flex line where it goes into the caliper. There is plenty of room up front. Put the new hose in caliper first - you have to spin the whole thing to screw it into the caliper.

Stock flex line going into the rear of a front caliper (320mm brakes) A brake wrench will have room to move past the crimped fitting to the section the wrench will fit. You make have to coax the line to run straight for that.

How the stock line terminates on the bracket where the hard line ends. The clip stays there basically.

Closeup of flex line where it goes into the caliper.

new stainless line in place

New stainless line running into caliper.

The rears are a bit more involved. First you need to put the parking brake into maintenance mode. Then you are going to want to remove the caliper. I found it quicker to do this because of the clearance issues, I could not get a good bit on the caliper end of the line with the caliper in the car. YMMV. It's just 2 bolts and an electrical connector anyhow. Otherwise it's the same as the front. Caliper end first, then connect to the hardline at the bracket.

use a straight pick to remove the electrical connection for the EPB. Just push it straight in where the ridge is. (RH side of this pic)

The rust on the caliper was amazing; the flex line just buckled when I tried to remove it. I had it off the car, in a vise and soaked in Kroil. It was not interested.

New part, old part. The new part comes with the EPB assembly which is really handy.

it sticks out, but it works great.

Make sure your grommets are snug into the brackets that hold them. You don't want the lines rubbing against anything that would cause wear.

In my case 3 of the 4 corners were really easy. The 4th corner was a mess. The LH rear corner of the car is vexxed. It's the same place I had to cut the rotor off. Now the hose would not come out of the caliper. I replaced the caliper with an OE spec TRW part which was about 1/3 the cost of the same thing in an Audi box.

Bleeding/flushing the brakes in the A5 requires you to use a pressure bleeder that has can deliver 2 bar (29 psi). The bleeding order is a bit funky as well. left front, right front, left rear, right rear. Let it run until there are no more bubbles and the fluid is nice and clear. I've got 15psi here as a test before I put the brake fluid in. You want to make sure you can maintain pressure, not just in the braking system but in the pressure bleeder & its hoses. Leave it for 5-10min and make sure it doesn't leak out.

At the end, reset your electronic parking brake and you should be good to go with a nice firm brake pedal, and hoses that will actually come out properly if necessary.