Brake Questions for a DIY'r

[BLITZEN]

Sorry I know there have been a lot of Brake threads lately. But I need to know a couple things...

First, how thin/thick can you wear the pads before digging into the rotors? My dealership said I (fairly desperately) needed new front and rear pads. But when I got the rear apart today (which were supposed to be worse than the front), the pads had more than half the thickness of the brand new pads still left. There was probably 1/4-inch of material, so I left them on. Are they toast? Or was the dealer selling me something I didn't need right away?

Second, do I have to open a bleed valve or something in order to compress the piston/slave cylinder? It didn't want to compress very easily.

I appreciate your wisdom as I'm usually a white collar rat and this is the first brake job I've done on an RS6.

Thanks! :thumb:

[Rupert]

Hi BLITZEN,

Someone on RS246 commented that their RS4 sensors come on when there is about 3mm left. I've been down at maybe 4mm and the sensors haven't broken (on the fronts, obviously, there are no sensors on the rears).

1/4 inch sounds like a lot of pad material left, for many thousands of miles.

The rear pistons will need a caliper rewind tool. It turns the piston as it compresses it. You may be able to rewind them with a pair of pliers, but it's so much easier with the rewind tool.

Do not press the brake when you have the rear caliper off though. You can damage the piston if it comes out too far.

Remember to loosen the top of the brake fluid reservoir, keep an eye on the level as you push the pistons back in, and use a syringe to suck some fluid out if needed.

[hahnmgh63]

As mentioned the rears need to be compressed while threading the piston back in clockwise. So: push and turn. The tool is much easier but in the past I was successful with a set of heavy needle nose pliers that only opened far enough to catch both grooves on the piston, don't stab yourself. The front pistons just push in, it is best to lay something flat in there across two pistons and use a clamp and compress two at a time. You will need to hold the opposite side (of the caliper) so they don't pop out further when you compress the other two.

[BLITZEN]

So does anyone know exactly how much pad you can wear before doing damage? Are OEM pads glued to the steel plate or riveted?

[JCT2033]

I just had my front brake pads and rotor replaced this week. It all started with a grinding noise coming from the front wheels.
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I was told by my local deal the following: Under RS6’s original free maintenance program, Audi would not change the brake pads until it’s less than 5 mm. The sensor is set to come on at 2 mm. In my case, the pads had about 4 mm and they were grinding the rotor, hence, damaged the rotors. The front break set up on the RS6 pushes the pads hard enough to create the grinding even through there still 4mm left on the pads.