2013 camhead brakes

[Hadabadachada]

I gotta make a YouTube to address all these questions I have. Should have been doing it with the S for awhile now….

 

so new to me bike, great bike. Interesting brakes. Seems that it’s all servo stuff from BMW now, okay, I have a little experience with the earlier type..

 

Anyway, rear brake is major spongy, by itself. I can mash it and get the abs to kick but not much power, thinking more, that’s the way it is…

front brakes, maaaaybe a little soft, that’d be nit picky, but maybe they are soft. They work good none the less.

 

now the servo. So I notice when I pull the front brake with some okay force, and then hit the rear, the rear is RIGHT THERE! And hard, ayoooo! 
If I’m more relaxed pulling the front, the rear stays mushy. Sometimes I feel/sense a sort of click in the front lever, I’m assuming kicking the rear into full on…shrug.

 

im assuming this is normal for this servo/bike? Rears aren’t much of anything and assistance can be strong?

 

Fluid in master looks brand new, but how do I know they didn’t just drain it and refill? 

any pointers for bleeding? Is it straight forward or do I have to bleed 86 nipples under the gas tank?

I saw a post mentioning a vacuum jobby, is that a must on this system?

 

 

[Hadabadachada]

…..Waiting on my Haynes, maybe pick up a clymers soon, they still make books?

[lkraus]

2006 was the last year that BMW used the servo brakes.

[pwillikers]

Your brakes should not feel mushy.  Mine are anything but.  These brakes are linked.  When front brake is applied, the rear brake is activated. Applying the rear brake is additive to the linked activation.

[Hadabadachada]

I just ripped around the streets a bit, i say, at speeds the brakes feel good, right on. rear alone, not really mushy, not the strongest.

 

I guess it’s primarily at slower speeds, first and seconds around town, rear has to be pushed half way + and doesn’t feel very strong. 
And that’s when I usually use the rear, low speed round town. 
 

up over 40mph brakes feel great. 
not really a big deal, just posting my experience on this my new steed. 
 

say, can I bleed the clutch master to bleeder? Or is it recommended to do the bleeder up syringe thing I saw on the tube?

did I post that question already?

My sugar is low.

[dirtrider]

11 hours ago, Hadabadachada said:

I gotta make a YouTube to address all these questions I have. Should have been doing it with the S for awhile now….

 

so new to me bike, great bike. Interesting brakes. Seems that it’s all servo stuff from BMW now, okay, I have a little experience with the earlier type..

 

Anyway, rear brake is major spongy, by itself. I can mash it and get the abs to kick but not much power, thinking more, that’s the way it is…

front brakes, maaaaybe a little soft, that’d be nit picky, but maybe they are soft. They work good none the less.

 

now the servo. So I notice when I pull the front brake with some okay force, and then hit the rear, the rear is RIGHT THERE! And hard, ayoooo! 
If I’m more relaxed pulling the front, the rear stays mushy. Sometimes I feel/sense a sort of click in the front lever, I’m assuming kicking the rear into full on…shrug.

 

im assuming this is normal for this servo/bike? Rears aren’t much of anything and assistance can be strong?

 

Fluid in master looks brand new, but how do I know they didn’t just drain it and refill? 

any pointers for bleeding? Is it straight forward or do I have to bleed 86 nipples under the gas tank?

I saw a post mentioning a vacuum jobby, is that a must on this system?

 

 

Morning  Hadabadachada

 

now the servo. So I notice when I pull the front brake with some okay force, and then hit the rear, the rear is RIGHT THERE! And hard, ayoooo! 
If I’m more relaxed pulling the front, the rear stays mushy. Sometimes I feel/sense a sort of click in the front lever, I’m assuming kicking the rear into full on…shrug.

 

Your 2014 is still a partially servo assisted even though BMW it pretty tight lipped about that. 

 

Using the front brake lever only, you are getting standard direct hydraulic front brake actuation & servo-pump assisted rear brake apply. 

 

Using rear brake pedal only you are getting rear-brake direct hydraulic brake apply (no front braking input to the rear at all) 

 

Where it gets confusing is when using the rear brake pedal in conjunction with the front lever. 

 

When using the front brake (non ABS event) then the  rear brake is normally servo assisted & stays servo assisted UNTIL you add more rear pedal braking pressure to the rear brake than the servo is supplying.

Once your rear foot brake pressure exceeds the front servo pressure to the rear brake then that shuts off the servo pressure going to the rear & the rear pedal pressure then becomes the applying rear brake force.   Then if you pull the hand brake lever harder (so servo pressure exceeds rear pedal pressure then the servo takes back over as  the rear braking control.

 

So, with key-on__

 

Front lever only, you get front brake direct hydraulic apply & rear brake servo apply.

 

Rear brake pedal only, you get only rear brake pedal direct hydraulic apply. 

 

Both front lever & rear pedal apply, you get direct hydraulic front brake apply but the rear brake is applied by the servo only, or the rear brake pedal only (you can't have a combined rear brake apply).

 

So pull the hand lever lightly & you and get standard front brake hydraulic apply with servo pump rear brake apply (say 100 lbs apply pressure).   Then step on the rear pedal lightly (say 80 psi apply pressure), nothing changes as the rear brake output pressure is just deadheaded & adds nothing to the rear braking pressure. 

 

Now, with the hand lever still pulled lightly you are still getting standard front brake hydraulic apply with servo pump rear brake apply (say 100 lbs apply pressure).   Then step on the rear pedal hard (say 120 psi apply pressure), the rear brake output pressure is now higher than the servo apply pressure so the servo pressure becomes deadheaded & the rear pedal pressure takes over rear braking control. 

 

Due to how hydraulics work you can't have 2 (combined) pressure inputs into the same single  (one line in) hydraulic caliper. 

 

So an easy way to think about your rear braking is whatever end (front lever or rear pedal) that is supplying the highest pressure to the rear caliper wins & has full control of the rear braking. 

 

If your brakes are a bit spongy then it sounds like you might have a little air in the system, or possibly you are not used to them yet as they are not as abrupt as your old full servo assisted (wizzy) system. The rear brake pedal getting a bit harder with front brake lever usage can be normal as the rear pedal is probably just deadheaded (goes nowhere) unless you step on it with high force.  

[Skywagon]

Hadabadachada.. I can’t give you the technical explanation DR has, but will share with you my BMW brake experiences. My last bike was a 2005 1150RT. My current bike is a 2014 RT. IMHO the brake systems were designed to be used together. On my 2005 you could stand on the rear brake by itself and it was terrible. Using front and back together it was great and super sensitive. On my 2014 if you use the rear brake alone, it’s terrible. If you use them together they are really good and conventional. On the 2014 you can turn the ABS off between starts. When it is off the rear brake by itself is better but still have to use a ton of force to skid the tire. I really don’t care for the linking, but love they have ABS, and I understand why BMW does link them

[9Mary7]

Bleeding is straightforward.... just bleed them straight thru.

[Bernie]

If the bike is new to you, it could be that someone installed some real cheap brake pads.

You may want to replace them with a set of quality name brand pads.

 

[Hadabadachada]

Thanks. I’ll be doing a bleed, I can only assume they’ve never been bled in 10 years.

bike has 3800 miles on it, doubt anything’s been done. 
 

good to know about the bleeding. I’ll be bleeding the clutch too. Just bought one of those syringes for the clutch job. 
looks like mineral oil for that?

 

 

[dirtrider]

10 hours ago, Hadabadachada said:

Thanks. I’ll be doing a bleed, I can only assume they’ve never been bled in 10 years.

bike has 3800 miles on it, doubt anything’s been done. 
 

good to know about the bleeding. I’ll be bleeding the clutch too. Just bought one of those syringes for the clutch job. 
looks like mineral oil for that?

 

 

Morning   Hadabadachada

 

When you are ready to do the brake bleeding post back just before you start as there is way to get the rear servo to run so you can bleed that. With your unknown history on that motorcycle you might want to shim the front brake pads back (pistons retracted in their bores) so you get more old fluid out plus you then re-fill the front brake reservoir to the CORRECT level.  

 

On the clutch fluid replacement, do not over-fill the reservoir after as the clutch fluid actually raises in the reservoir as the clutch wears.