Rear brakes heating after installing new BOSH disks and brake pads

[avuthless]

Good day.

Last week i had vacation and i did not find any better activity on holidays as to work on my car . My wife did not mind too much

So i upgraded my Audi A6 3.0tdi quattro brakes from old factory ones (still original) to new BOSCH ones. Also installed new bosh brake pads as well. My parking brake is electronic btw.

So this week i was driving to my work and when yesterday i came home and parked my car in garage i noticed metal "ticking" from heat. I noticed that my muffler is quite hot and my rear wheels produce heat too. The rims (original aluminium) did not heat up very much (was warm like 36-42 C) but i could feel the heat from my disks from distance (did not want to touch that though). Front brakes are ok, and do not heat up that much (maybe because they are ventilated and rear ones are not).

So now i have a new headache! I am afraid my rear brakes may overheat or i may damage them in some way. Whole set of brakes + discs had cost me very decent 400 euros (i am from Germany) and this is quite low price since i bought them from known supplier.

Any of you changed their brakes and noticed such behavior? Should i ignore this since my disks and pads are brand new or must/can i do something? The gray coating on disks had gone away at disk/pad touching surface (as it must be).

Thanks for any help!

[c4a5er]

Did you use VCDS to retract the EPB adjustment in the calipers and reset afterwards?

[avuthless]

No i did not. I could not get my hands on it so i used one of many "manual EPB retraction methods". I did not open and play with clockwork manually, but i did provide manual operating power to retract parking brakes. After that i used my parking brakes few times and they showed no errors and worked wonderful. ATM it works ok and does not give any problems. After todays driving i heard some squeaking noise from my right rear wheel. I guess brake pads became squeaky after heating up. The wheel rim was quite hot (just right one though) all other wheel discs brakes where moderately hot (since front ones were hot too, i guess it was normal).

I did have issues with my previous brakes on rear right wheel (same that heats up now). There is a metal plate that allows brake pads to move. The right one has some damage from inner-side and one brake pad does not move very smooth. Maybe it got stuck? Will order new ones for both wheels and will change them this weekend. (Sidetracking but will perform diesel system purge too).

Tried rolling with car and brakes do not block wheels (at least not always and not very strongly). So car does roll on neutral (i have manual transmission) and just minimal braking power is felt (not always).

Hope i won't cause more damage til' weekend.

[Peter D]

You need to use VCDS to retract and then reset the EPB's.
What 'metal plate', are you referring to the guide clips. Exactly which brake calipers do you have. Regards Peter

[avuthless]

Sorry for my bad terminology. I was referring to brake caliper pad clips. Well i cannot atm tell you exact part number of my brake calipers, but there are two that goes to 2006 165kw 3.0tdi quattro. Ones are wider and uses vented disk brakes (i am talking about the rear axle) and thew ones that are "regular" and uses not ventilated discs. In my car i have these "regular" ones.

So i just ordered new set of brake caliper pad clips for whole rear axle. Will change them this weekend (if shipping will be fast enough).

Yes, VCDS with ross-tech cable or specialized tool is required to retract EPB's and then reset them. But since i did not have any of those, i used other method to do that. I provided power to EPB motors to retract my brakes and then let the car reset them for me. I know it sounds crazy for some but i did not invent this and if done right it does no damage. Currently my EPB is not causing any issues, they both work ok, car shows no errors (i checked with diagnostic tool) and wheels seem "less blocked" than few days ago. But my rear right wheel is still braking a bit (it was doing that with old brakes before i did anything to EPB). I suspect brake caliper pad clips.

Since i detect this thread may side track, i will try keeping it on track.

Rear and front brakes are heating less than few days ago when they were "fresh". If by the end of this week all brakes will act normal and only rear right wheel issue remains (which is an old issue of my car), i think it will be safe to assume, that new brakes and pads may heat a bit more while they are new. Maybe this will help any future people who stumbles upon such "issue".

[avuthless]

Since every day i am driving to my work the same road, and this road is basically 30/50/70 km/h roads i can measure my brake temperature quite precisely. Average speed of my trip is 40km/h and i take approx 28-30 minutes from "got out of house" til' "got out of car". The track length is 17,4 km. Fuel consumption on my 3.0tdi with mechanical gearbox is ±8,5 liters / 100km.

When brakes were heating, i was seeing 9.5 or higher fuel consumption in my car. Yesterday i had 8.9 and brakes were moderately hot, today i reached 8.4 and brakes are pretty cool. No big weather temperature drops/rises this week. The faulty brake on rear right wheel also heats a little less than before, but all other brakes are really quite cool.

I also noticed than even though i felt yesterday morning that car does not roll that good after coming to work, i left it with EPB turned off and in the evening, when it was all cool, it rolled like it should (my parking spot is a bit downhill, so i feel as soon as i hit the clutch). So cooling metal may have gotten tiny bit smaller and therefore less friction.

So even though my measuring is not perfectly reliable and my early "whining" is not worth of much attention, i think i can summarize this thread so: If brake disks and brake pads are replaced with thickest disks (yes my disc brake is max allowed thickness) and brand new pads, the remaining free space between pads and discs on fully retracted brakes (not pressed at all) may be too little and therefore if brakes are old they may still leave brakes touching even though not pressed at all. So if anyone stumbles upon hot brakes after changing them, big chance it will just go away on its own after some driving.

I am happy that i noticed this in winter time (summer would allow brakes to heat up much much more) and i am happy for all of your time and help in this. I will update this thread one last time after i change my rear pad clips just for confirmation that my brakes are in good condition after all this. (Because i will dismantle all four brakes this weekend to check on one-week wear amount + rear pad clip change).

Oh yeah, and i will try using Wynn's Diesel System Purge on it too, this is totally off-topic but if anybody would be interested i can make new thread with pictures and story on how it all went for me.

[avuthless]

So after a week i can say that brakes do not heat up at all. Stay cool as they should. Just the rear right wheel gives me troubles.

Even though i changed brake caliper pad clips for both rear brakes, it seems that the right one is still not willing to retract easily. I'm hoping it may be the brake caliper screws (ones with rubber on them). If not - i would be guessing its the brake cylinder then. I will try changing screws, if that won't help - will change the cylinder.

[Peter D]

Did you check that the caliper was free to slide on the guide pins, and was the piston free to move back. Did you clean the guide pins and did you lube them with anything. Use the wrong stuff and they can swell up and cause a problem. Regards Peter

[avuthless]

I did not check if piston was moving freely (did not come to my head at the moment) but i will check all this sometime this week. Thanks for help!

[royclark]

Also, don't forget to change your brake fluid every two years.