No rear brake pressure - 696 w/ abs

[ducpainter]

I know even less, and I'm usually wrong, just ask Jenn.

You were more easily convinced than I.

[Kev M]

You were more easily convinced than I.

Years of practice. 

[Speeddog]

Then should I expect the clutch and front brake to fail next?

I like Occam's Razor, which is why I checked for leaks and checked pads first. 

Well, that may be a bit of a jump, but not a bad idea to flush and bleed them too while you're at it.

[Charlie98]

I wonder if it's not something about that brake model.

My '13 796/ABS did the same thing last year.  It was fine all through the summer... then one day the pedal started to get a little mushy, a few weeks later it was done.  This was during the regular riding season, too, not in storage or anything.

I had my dealer flush and bleed it out and it seems OK now, but I think because of the way the system is plumbed... up to the ABS module, down to the swing arm, up through the loop and then back down to the caliper... it magnifies any shortcomings with the fluid or system.

[Speeddog]

796, and other models with the SSS and caliper on the bottom, tend to have issues with the system going soft.
I've concluded it's the hose routing and low-mount caliper that are the perpetrators.
Aided by many of those having the master cylinder mounted to the cases; 916 and later SBK, ST's and others.

ABS equipped models suffer from a soft lever and pedal, just due to the system volume and long lines, especially on the rear brake.

Some folks have fitted bleeder banjo bolts at the ABS unit with good results.

[Howie]

Normally I would suggest replacing the rear caliper.  You are correct Kev, it should not happen.  But it does with that caliper.  Bleeding seems to work most of the time.  It's the rear brake which many of us don't use anyway.  If bleeding doesn't work or last then worry.  Otherwise, 

Good explanation why this happens?  Beats me.

[Kev M]

Ah, so it's a known problem.

I'm not sure if that makes me feel better or not lol.

Ok, just have to pick up some fresh fluid.

[EEL]

So I have had (and still have) this same problem on my 1100

Did you just have any service done recently? Specifically a valve adjustment or timing belt service?

The reason I ask is since the exhaust from the front header needs to be taken off to get to the belts, sometimes the slip fit exhaust connections get installed slightly mis-aligned and the header gets too close to the abs brake lines that are generally routed directly below the header and up to the front of the bike.

The heat from the bike literally starts cooking the fluid inside the lines.

The routing on the 696 is probably a little bit better than the SSS my 1100 variant  which is just poorly designed but the impact may still be there. Just throwing it out there for you to look at.

[Charlie98]

The reason I ask is since the exhaust from the front header needs to be taken off to get to the belts, sometimes the slip fit exhaust connections get installed slightly mis-aligned and the header gets too close to the abs brake lines that are generally routed directly below the header and up to the front of the bike.

The heat from the bike literally starts cooking the fluid inside the lines.

Interesting... I'll have to look at mine.  I'm fixing to pull my Y-pipe off, anyway.

And, duh, I forgot the routing would be different with the 696 vs 796/1100 because of the SSS.

[Kev M]

So I have had (and still have) this same problem on my 1100

Did you just have any service done recently? Specifically a valve adjustment or timing belt service?

The reason I ask is since the exhaust from the front header needs to be taken off to get to the belts, sometimes the slip fit exhaust connections get installed slightly mis-aligned and the header gets too close to the abs brake lines that are generally routed directly below the header and up to the front of the bike.

The heat from the bike literally starts cooking the fluid inside the lines.

The routing on the 696 is probably a little bit better than the SSS my 1100 variant  which is just poorly designed but the impact may still be there. Just throwing it out there for you to look at.

Actually sorta.

So at the beginning of last season we had a complete service:

Valves/Belts
Flush and refill of clutch and brakes
Fork oil changes
Etc.

But then we went through the whole season, only maybe 2k miles or so, but including a track day all with no problems.

Put her to bed around Dec, and woke her up kinda late this year (yesterday) thanks to a broken wrist but suddenly a brake problem seemingly out of no where after sitting.

<shrugs>

I'll report back after bleeding.

[Kev M]

Ok, I'm a slug (actually bought another new bike after this thread and been busy).

So today I finally check to see what I need for bleeding and noticed something weird.

The clutch and front MC reservoirs call for Dot 3 or 5, but the REAR calls got Dot 4?

Is that right?

[DarkMonster620]

you can you anything not less than DOT4 or if you feel spendy, DOT5.1

I used to use DOT4 and DOT5.1 at the dealership's shop and at home I still use DOT4/5.1[5.1 for newer vehicles with ABS] that for some reason make the later vehicles work better

[EEL]

never put in dot 5 if you have already used dot 3 or 4. you want dot 5.1

[Howie]

You can always use a higher DOT number as long as it is polyglycol based.  Silicone brake fluid was the first brake fluid to earn the DOT 5 rating.  It is not compatable with polyglycol fluids as originally thought so polyglycol has the 5.1 designation.

[Kev M]

Sorry, took way to long to get to this. Father's day spent the afternoon riding all the bikes in the fleet.

Ended with the 696 and threw it on the lift for an oil change and brake bleed.

Went through the capacity of the tiny reservoir about 3-4 times, was getting lots of air at first, but eventually firmed up.

I still need to test ride it, but I'm thinking that will fix it.

But man I'm freaked. From where the heck did all that air come?