Looking for a How To... front brake pads/rotors replacement

[gstrouse]

So I have been having pulsing in braking. Very annoying. From my experience, it was rear rotor warp. So, I replaced the rear rotors and pads. Still have the problem.
So thinking it's something like a warped hub. I decided to take it to the dealer since it's under warranty. They said it's front rotors are warped. Not sure why I don't feel anything in the steering wheel.
But, with that, they said $900 to replace the fronts. So I said I'd do it. But, I've never seen a front brake system like what is on this new B9.
So, i'm looking for "how to" instructions on changing pads/rotors front, on this b9 a4.
Any help would be very much appreciated.

[gstrouse]

Ok, so I figured out how this thing works. I didn't know that these had dual piston calipers. Both sides have pistons.
The is no traditional caliper hanger. It's all in one unit, and it mounds directly to the hub assembly.

[Smac770]

You need to know what front brakes you have before you can go finding instructions for them. On the front for the low power 2.0T FWD B9 A4, the 314x25mm rotor is paired with a single-piston floating caliper. For the high power 2.0T quattro B9 A4, the 338x30mm rotor is paired with a dual-piston fixed caliper (fixed, so it needs pistons in pairs, on each side). It's curious that they moved the B9 A4 quattro to fixed caliper like the B8 S4 (though not quite as large) and put the B8 S4 rear brakes on the B9 A4 quattro (330x22mm vented). I wonder if fixed is considered generally better performing than floating, or at least has higher performance thresholds? Seems the fronts are all Conti made, while the rears are still TRW made, for B9 that is.

"During the development of the wheel brakes, special attention was given to lightweight construction. Depending on engine type, a weight saving of up to 5 kg has been achieved compared with the previous model. The brake pads are now copper-free and therefore already meet the mandatory regulations which do not come into effect until 2021."

Not sure how they got lighter since they are certainly larger than they were before. No idea what the copper regulation thing is regarding the pads.

The brake details are documented in SSP 644, page 71.

[jac04]

The fixed calipers are 4-piston - 2 on each side. Once the caliper is removed from the carrier, the pads can be removed. I suggest removing the pad retainer spring (flat stainless clip) BEFORE removing the caliper, as it is much easier to remove this if the caliper is being firmly held.

The factory service manual states to replace the caliper mounting bolts with new ones, and torque to 200 N-m.

Make sure that the 4 small anti-friction plates stay in place on the caliper.

[harryn]

Question about the rear electronic brakes... does the method of reversing polarity on the brake motor still work to retract and engage the motor to the piston? In other words, is the electronic brake motor still two-prong? I did my rear brakes on my B8 a couple times using a 12v hobby battery, and two wires to retract and engage the motor for the piston. Worked like a champ and no errors/codes/lights at all. And the electronic parking brake worked perfectly fine as well.

Thanks

[wraedeohed]

This guy has a great walk through on how to do both the front and rear brakes.


https://youtu.be/DSscquK_dTc

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[wraedeohed]

Question about the rear electronic brakes... does the method of reversing polarity on the brake motor still work to retract and engage the motor to the piston? In other words, is the electronic brake motor still two-prong? I did my rear brakes on my B8 a couple times using a 12v hobby battery, and two wires to retract and engage the motor for the piston. Worked like a champ and no errors/codes/lights at all. And the electronic parking brake worked perfectly fine as well.

Thanks

Obdeleven has a brake change function to retract the rear brake pads.

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[harryn]

OBD Eleven has all of these functions? I thought it was just a code reader. Can it program batteries when we replace them, or any other part we replace that needs to be coded to the car?

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