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Discussion Starter #1
2006 Jetta TDI BRM DSG. I just replaced my factory rear pads at 81k miles. Everything was perfect until then.

Now I'm experiencing rear brake problems. First trip with the fresh pads down I-70 in Colo got the rear brakes so hot that they were smoking by the time my wife made it down to Silverthorne. Since then I have adjusted the park brake so that the calipers reset all the way to the arm stops, flushed the entire system with new brake fluid, and reset each rear caliper piston 5 times with bleeder valve open - in order to clean out as many contaminant particles as possible. Both rear wheels spin almost freely with just slight pad to rotor friction. Both wheels have the same resistance, the same temperature after driving, and same amount of brake pad wear - both new and old.

I am still having problems though. It seems as if the rear brakes are doing about 90% of the braking judging by the temperature of the wheel hubs after a normal drive. I can lay my fingers on either of the front wheel hubs, but I can just barely touch both of the rear wheel hubs to avoid getting burned badly. Also, the rear brake pads have 3k miles on them and are 50% worn - not good! I don't need to mention where most of that pad material is. I have read a lot about people saying that there is a rear brake bias on these cars. I know that there is EBD on it for the ESP so it is possible that the car can in fact bias individual brakes. Physics tells us that front brakes do most of the stopping on a vehicle. Our eyes tell us that the front brakes do most of the stopping on a vehicle because of the larger and vented rotor. Even if the there was a rear bias for light braking; it was completely transparent to me before I changed my own rear brake pads because I never had any squeaking or an inch thick blanket of brake dust on my rear wheels.

I'm stumped. And I'd love to know exactly how the rear calipers work with the self adjusting pistons and integral park brake. I did see a lot of both black and white particles in the brown brake fluid when flushing. A lot of particles were seen when reseting the pistons which I thought was a good sign that things were getting cleaned up a bit. But still problems...

Are there special procedures that I'm not performing or performing well? I have heard about pumping brakes 3 times, then applying the parking brake 3 times. Until someone can explain the exact functions this procedure performs on the calipers, I'll remain curious if not skeptical. I have read about some people having premature rear brake pad wear on their vehicles of various ages, otherwise I would point my finger at two faulty calipers.

But on the other hand, my rear brakes never behaved so badly until I changed the pads. This is making me wonder what I did to cause this? If anybody has any suggestions or ideas, I'd love to hear them! Thanks.
 

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Well, it sounds like the rear brakes are sticking for sure then. When you changed the rear brake pads did you turn the pistons while pushing them back? Why would they be sticking though if they spin freely at rest? I did some searching and found this photo of an Audi caliper's adjuster and the caliper side:




The way I see it, the caliper screw serves as a stop for the caliper piston.
 

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Discussion Starter #3
Awesome pictures, thanks. It seems as if the piston can rotate and move out when hydraulic pressure is being applied in order for the piston to self adjust. Then once the piston is pushing against the pad, the friction of the piston/caliper threads keeps the piston from rotating in the opposite direction.

Now the next question. Does the parking brake lever operate a plunger to pressurize the hydraulic fluid in the caliper? Or is it completely mechanical?

Thanks.
 

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Discussion Starter #6
Problem Solved!

After thinking about it, I decided to get a set of genuine VW brake pads. That made all the difference and was worth every penny. My brakes do not squeak anymore and the quality of the VW pads was far superior to the after-market pads I got at Advanced. At four times the cost, it does hit the wallet harder, but the quality is well worth it - plus the pads come with new carrier fasteners and new pad retainer sleeves. I don't know why I even bought third party pads in the first place. Lesson learned I guess...

I did talk with a couple of VW/Audi techs. They said that MKIII and MKIV Jettas exhibited faster rear pad wear than front, but that the MKV cars generally had the front and rear pads wear at the same rate.

Thanks for your help guys.
 
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