Excessive brake pedal travel until pads hit rotors

[threeputtpar]

2015 Audi Q5 2.0t - It seems to me that the brake pedal travels an unusual distance before I get any braking action, far more than any other car I've owned. Once the pads contact the rotors there's plenty of stopping power to overcome the tire's grip.

All new pads and rotors around, bled the system both the old school way and pressure bleeder with no change. I watched the rubber brake hoses while my son worked the brake pedal and nothing was out of the ordinary. No leaks anywhere.

What else should I be considering? Brembo 4 piston calipers up front and single piston ATE calipers in the rear. Yes, I did crack open both bleed screws on the Brembos.

 

[Snagglefoot]

I'm thinking you are compressing air still locked in the system. I'm not sure about your bleed screws but maybe the highest one is the last to bleed. I use a pressure bleeder AND a piece of tubing with a large loop going into a plastic bottle partially filled with brake fluid. (Belt and suspenders).

 

[mk378]

If the rotors wobble it will push the brake pads back farther than they should be when the car moves. Test by pressing the pedal repeatedly with the car not moving (but engine on).

 

[Nukeman7]

I can only think of 3 possibilities:

a) The master cylinder internal seals are beginning to fail,

b) Trapped air inside the hydraulic brake system/ABS module, or

c) Improperly adjusted clearance between the brake pedal push rod and the master cylinder plunger bore (most likely if the master cylinder has been replaced).

 

[Rand]

Did it do this before the brakes were replaced?

 

[HemiBenny]

Did you replace the pads and rotors as a result of these symptoms, or have these symptoms manifested since the replacement?
Replacing pads and rotors will not introduce air into the system. There's no need to bleed it.
Some people crack the bleed screw to retract the piston into the caliper, although there's no reason to do this IMO, but this still shouldn't introduce air into the system.

What started this trip down your rabbit hole?

 

[TiGeo]

I believe these are the same calipers as the Macan. It's a known issue and there are some fixes here. Firet post should have the info.

Thread 'Consolidated Macan Brembo upgrade thread (READ FIRST POST)' https://golfmk7.com/forums/index.ph...brembo-upgrade-thread-read-first-post.371028/

 

[edyvw]

2015 Audi Q5 2.0t - It seems to me that the brake pedal travels an unusual distance before I get any braking action, far more than any other car I've owned. Once the pads contact the rotors there's plenty of stopping power to overcome the tire's grip.

All new pads and rotors around, bled the system both the old school way and pressure bleeder with no change. I watched the rubber brake hoses while my son worked the brake pedal and nothing was out of the ordinary. No leaks anywhere.

What else should I be considering? Brembo 4 piston calipers up front and single piston ATE calipers in the rear. Yes, I did crack open both bleed screws on the Brembos.

What pads?

TiGeo gave you link that might be an issue, but what are pads you used?

 

[Snagglefoot]

In the defence of bleeding, as we all know, replacing brake fluid should be done on a periodical basis. When doing pads and discs, the wheels are off and there is good access to the bleed screw. I will often bleed from the master cylinder to the calipers after installing new pads. Doing all four wheels is best, but that calls for a special session in your busy life.

Also, for those who crack the bleed screw when pushing the calliper pistons back in, if I’m going to be cracking a bleed screw, I will also go all the way and bleed fresh brake fluid into the master brake cylinder to the callipers using my pressure bleeder.

 

[KrisZ]

It could the real caliper if it has an integrated parking brake.

I had that happen on my Grand Caravan and it turned out out that, once you get the caliper retracted all the way in by turning it, you’re supposed to turn it out a little so that it’s a snug fit when you put it on the rotor.
Sounds weird and one would think the hydraulics would take up the slack, but my pedal travel was unusually long.

Doing the above brought pedal travel back to normal.

 

[50yr Street Mech]

Air in system / air in master cylinder / air in ABS unit./ bad master cylinder....Not an easy one..Good luck