Rear brakes

[r12gecko]

Did the pads today. I have 12,000 km on my bike. The fronts still have about 3-4mm of friction pad remaining - I left them in place after a bit of clean up. The back, which I was replacing due to some spilled oil from my final drive box leak a couple weeks ago, were just about down to the metal. Seems our integrated system really leans on that rear binder.

[towerworker]

I agree, have replaced my rears twice in 38,000 miles. I seldom touch rear brake on my 04 w/abs.

[hjsbmw]

Did the pads today. I have 12,000 km on my bike. The fronts still have about 3-4mm of friction pad remaining - I left them in place after a bit of clean up. The back, which I was replacing due to some spilled oil from my final drive box leak a couple weeks ago, were just about down to the metal. Seems our integrated system really leans on that rear binder.

Do you have black dust on the rear rim? That's not 'normal', and there is a fix for that. Don Eilenberger pointed that out on the MOA forum a while ago. You have to apply some grease (little) to the sliding posts of the rear caliper, the ones that are protected by the tiny rubber boots.
Since I did that my bike rolls lighter, and I no longer hear the rear brake grind when I push the bike in the driveway.

Maybe we should have a sticky that summarizes essential tasks and improvements like this?

[Jed]

Do you have black dust on the rear rim? That's not 'normal', and there is a fix for that.

Huh ?? I have brake dust that collects on both rims - rear worse than front. I have no doubt that I should lube the posts that the rear caliper runs on - in order to minimize dragging of the rear brake (single sided piston system). But brake dust is a fact of life isn't it? What concerns me more is the ever so light oil splatter that seems to get on the rear rim. I assume it's weep-age from the FD but I need to have a closer look at the seals to be sure.

[hjsbmw]

Do you have black dust on the rear rim? That's not 'normal', and there is a fix for that.

Huh ?? I have brake dust that collects on both rims - rear worse than front. I have no doubt that I should lube the posts that the rear caliper runs on - in order to minimize dragging of the rear brake (single sided piston system). But brake dust is a fact of life isn't it?

Make that excessive brake dust on the rear, together with a grinding sound when pushing the bike. That can be minimized or even eliminated with a bit of lube. If the pads are worn after 12,000km, around 7,500m, then that's not a fact of life unless your name is Valentino.

[Jed]

Make that excessive brake dust on the rear, together with a grinding sound when pushing the bike. That can be minimized or even eliminated with a bit of lube. If the pads are worn after 12,000km, around 7,500m, then that's not a fact of life unless your name is Valentino.

Thanks for the clarification, sorry if I took your post too literally. I hate cleaning my bike but after 15K miles, I'm still on my first set of pads (front and rear) and I've only cleaned the bike twice. So I guess that I'm not experiencing excessive pad wear or dust build-up.

Do you guys experience light oil splatter on the rear rim? Ideas about where it comes from?

Cheers,

[mogu83]

Jed,
Did you drop the rear drive fluid to 180ml. I was getting seepage around the right side seal (which ended up on the rim mixed with brake dust) till I dropped the level to the new improved (approved) level. I then went to EBC metallic pads and EBC disk on the rear. The rear rim is now always squeaky clean and the rear brake seems to have a little more bite (the way I like it).

I know I'm asking for accelerated disk wear with the metallic pads but EBC disks are cheap and I can afford one every 30/40K miles.

[Jed]

Jed,
Did you drop the rear drive fluid to 180ml. I was getting seepage around the right side seal (which ended up on the rim mixed with brake dust) till I dropped the level to the new improved (approved) level.

My local dealership did the FD oil change @ 12K miles - so I don't know, maybe they overfilled a bit. It's not a lot of seepage and brake dust build-up - but it is an annoyance. I last cleaned the bike 3K miles ago. The rear rim isn't too dirty but it's not clean either. Thanks.

[r12gecko]

Yep, I applied a little grease (careful to keep away from working side of the pads). Just got the Haynes manual - it recommended same thing. Hard to tell about build-up of dust... nothing on the rim & the brake area seemed mostly ok, with predictable filth because I'd got some oil there doing the fd. I would imagine the rapid wear-down of the pads added some stuff to the mix. Another necessary thing when doing the pads is ensure you get the calipers nice and clean with brake cleaner before you push them back into the housing - otherwise, they're going to carry dirt in there & score the seals.

If you have oil dripping onto the rim, something's wrong. Do a 10-20 km ride to warm up the fd, then get a light and closely inspect the filler seal - you have to position the wheel just so in order to see it without taking things apart - on mine I could actually see a bit of oil bubble out when it was warm before I fixed the o-ring. That oil drips directly down from there across the axle and gets sprayed onto the rim. I read here that synthetic oil has been associated with leaks, but I'm running synthetic back there now & no issues in several weeks now.

[deilenberger]

I regularly went through rear pads at around 11-12,000 miles (still on original rotor..) and the back wheel would get dirtier then the front - and get dirty faster. Since lubing them - at around 36k - the pads still have about 1/2 the material on them now at 47,000 miles, and the rear rim no longer is an eyesore.. it actually gets MUCH less brake dust then the front, which is what I'd expect since the front does the majority of the braking.

Simple test for'ya - go for a ride. Stop, dismount, walk around to the other side of the bike - and VERY carefully see if you can touch the disk without burning yourself (I have raised a blister this way so be CAREFUL!).. if the rotor is HOT - your brake is dragging and the pins need lubing. I've seen it on bikes with 600 miles on them. Apparently whoever assembles the brakes may have forgotten this little task.

All you need is a small smear of some hi-temp grease on the pins. I used Wurth-3000 (very sticky stuff, good at temps also.) You can do it with a Q-tip.. take the pads out so you can move the carrier back and forth on the pins, pull the little accordion boots back, put the grease on, work the carrier back and forth on them. Put pads back in and ride on... takes longer to type it out then do it.

Brake dust will be a thing of the past..

[Patch]

You have to apply some grease (little) to the sliding posts of the rear caliper, the ones that are protected by the tiny rubber boots.
Since I did that my bike rolls lighter, and I no longer hear the rear brake grind when I push the bike in the driveway.

Hmmm... just finished cleaning my bike for the 1st time... just completed 1200 miles of rain/muck over the past week and now i am hearing a "rubbing" squeak sound coming from the right front caliper. It kind of sounds like the tire is rubbing (it is not). New noise for me and my new 2011 R12R. Should I just re-spray the caliper with the hose? I hear it when pushing the bike and i don't want any un-needed friction or other issues as I'm still 400 miles from home!

any ideas... this pretty normal?

[Steve in VT]

Yesssss - the answer I've been looking for!! The dry dust on the inside of my back rim was the first clue, but the clincher was Don's "Finger-on-the-rear-brake disk" test. Sure enough, after less than 10 miles, the rear disk on my '07 was so hot I couldn't touch it. Funny thing, though. After a longer ride (>50 miles) the disk was merely warm. You can bet tomorrow I'll be greasing up my caliper pins.
By the way, has anyone noticed a distinct pulsing of the rear brake - as if the antilock function is engaging - when applying the front and rear brake simultaneously at low speed? Am I not supposed to use the foot pedal at low speed?