WHY BLEED BRAKES??

[bobbybob]

Maybe I've just missed this somehow. I have a 2007 R12RT, 3 weeks old, just put 600 miles on it. WHY do the brakes need bleeding RIGHT NOW? What bad thing is gonna happen if they are not bled now? Or is this just more nonsense from BMW to keep their dealer service depts. busy?

[ShovelStrokeEd]

OK, actually there are 3 different processes at work here.

 

Initial bleed, such as performed at the 600 mile inspection.

Done to get that last bit of air out of the nooks and crannies of the system that the original fill at the factory likely missed. 600 miles of driving/riding should also have bedded in the pads as well. The very act of pouring the brake fluid from the can will allow a bit of air to mix with the fluid and, under pressure cycles this can become free air in the system.

 

Maintenance bleed such as might be performed after a brake pad change.

Large movements of the pads coupled with the venting of the brake system when you push the pistons all the way back to allow the new pads room to install can cause some air to introduce into the system. Restores nice tight feel at the bars and pedal.

 

Fluid replacement. Not strictly a bleed but done in a similar manner.

Brake fluid wears out. It is both hydrophilic and hygroscopic and your system is not really as tight as you might think it is. Again, during the pouring process, the fluid will absorb some water from the air. Time/temperature cycles aggravate this process and the fluid will gradually change in characteristic. Chief of the characteristics that change is the boiling point of the fluid. Brake components get hot and get really hot under high effort braking. The last thing you want is for the fluid to turn to a gas and compress while you are trying to get your bike stopped. Also, water, the principle enemy here, is corrosive to the components of the system. A rusted piston will stick or cause the seal on which it rides to leak. Neither is a good thing.

 

Other than those, no real reasons to bleed the fluid.

[bobbybob]

Ed, thanks for the great detail. But I'm thinking--brake fluid is hygroscopic--how is MY re-fill (or dealer's)at 600 mile bleed time gonna be any different than the factory's original? Just another opportunity to get more water introduced into the system? My brakes work GREAT! So why do this and expose the system to more pollutants when it works great? Are you saying that "Yes--this really is just more nonsense from BMW"?

[bobbybob]

Actually, I just read the BMW checklist for the "1000 km Running-In check" I received from my dealer and there is no mention of needing a brake fluid bleed?

[ShovelStrokeEd]

I didn't say noffin'. Nope, not me. I live in a coastal swamp where a good day has relative humidities over 60%. I also back fill my cans of brake fluid with dry Nitrogen to minimize the effects. I was also being picky as there is a time of exposure factor as well.

 

Just another form of religion. Pick your deity and decide how you will worship.

[marcopolo]

Actually, I just read the BMW checklist for the "1000 km Running-In check" I received from my dealer and there is no mention of needing a brake fluid bleed?

 

Where then did you get the idea that you had to have your brakes bled at 600 miles?

[elwoodpone]

At 600 miles it's you that gets bled.

[bobbybob]

At 600 miles it's you that gets bled.

 

You said THAT right! Actually, where I got the impression that the brakes needed to be bled at 600 miles was by reading posts in this forum. But perhaps I mis-read something. I am going to call my dealer and ask what they do at 600 mi and what the charge is--will be interesting. Then I'll do as much as I possibly can!

[steveknapp]

It's a yearly service.

[marcopolo]

At 600 miles it's you that gets bled.

 

You said THAT right! Actually, where I got the impression that the brakes needed to be bled at 600 miles was by reading posts in this forum. But perhaps I mis-read something. I am going to call my dealer and ask what they do at 600 mi and what the charge is--will be interesting. Then I'll do as much as I possibly can!

 

Now that you've read the BMW check list you can see there's no brake bleed. It's essentially oil/filter, adjust the valves, synch the throttle bodies, and re-tourque the cyclinder head fasteners (the only time they're done for the life of the bike!!). Probably not listed on the check list you saw was flushing/refilling the final drive (that's a relatively recent change; was originally supposed to be a lifetime fill, but BMW changed their mind. In theory it's now another once-in-a-lifetime deal, but I think many of us will do it fairly routinely, for the sake of a small amount of fluid and 30 mins labour).

[Satguy]

Actually, the interval has been changed to every two (2) years for the newer bikes with the stainless steel/teflon lined brake hoses like the R1200RT. Less $$$ out of your pocket and less profit for the dealers.

[bobbybob]

At 600 miles it's you that gets bled.

 

You said THAT right! Actually, where I got the impression that the brakes needed to be bled at 600 miles was by reading posts in this forum. But perhaps I mis-read something. I am going to call my dealer and ask what they do at 600 mi and what the charge is--will be interesting. Then I'll do as much as I possibly can!

 

Now that you've read the BMW check list you can see there's no brake bleed. It's essentially oil/filter, adjust the valves, synch the throttle bodies, and re-tourque the cyclinder head fasteners (the only time they're done for the life of the bike!!). Probably not listed on the check list you saw was flushing/refilling the final drive (that's a relatively recent change; was originally supposed to be a lifetime fill, but BMW changed their mind. In theory it's now another once-in-a-lifetime deal, but I think many of us will do it fairly routinely, for the sake of a small amount of fluid and 30 mins labour).

 

Mark, thanks for the update--sounds like I could maybe do it all! Is there a place I can go (here or elsewhere on the web) that explains the finer points of things like torquing the heads, adj. valves. etc. If there was a tech day somewhere close I would probably go there too, but don't have any info. on them. Thanks again.

[marcopolo]

At 600 miles it's you that gets bled.

 

You said THAT right! Actually, where I got the impression that the brakes needed to be bled at 600 miles was by reading posts in this forum. But perhaps I mis-read something. I am going to call my dealer and ask what they do at 600 mi and what the charge is--will be interesting. Then I'll do as much as I possibly can!

 

Now that you've read the BMW check list you can see there's no brake bleed. It's essentially oil/filter, adjust the valves, synch the throttle bodies, and re-tourque the cyclinder head fasteners (the only time they're done for the life of the bike!!). Probably not listed on the check list you saw was flushing/refilling the final drive (that's a relatively recent change; was originally supposed to be a lifetime fill, but BMW changed their mind. In theory it's now another once-in-a-lifetime deal, but I think many of us will do it fairly routinely, for the sake of a small amount of fluid and 30 mins labour).

 

Mark, thanks for the update--sounds like I could maybe do it all! Is there a place I can go (here or elsewhere on the web) that explains the finer points of things like torquing the heads, adj. valves. etc. If there was a tech day somewhere close I would probably go there too, but don't have any info. on them. Thanks again.

 

I think you'll find from previous posts that even the folk who do all their own maintenance often have the dealer do the 600 mile running-in check precisely because of the re-tourquing of the cylinder head fasteners (that once in a bike's life procedure). It would seem the reason was that people did not want to give BMW, or their dealer, any resaon to hassle them over any future warranty work.

 

Not a consideration for me, as the most I do is change the oil/filter.