K11 Owners Group

slipperyox

Replaced a metal brake line under the tank. while I was at it, I cleaned the calipers (removed the pistons etc).

All back together and I have bled all air from master to abs2, from master to calipers using syringe vacuum, and even reversed with pumping fluid back up calipers to master and calipers to abs, lever still spongy.

There is no air in the fluid....????
I even checked the rubber hose sections for bulging, but none..
_________________
Luck is when planning and opportunity meet

DaveVoorhis

slipperyox

Flying Duck · Posted: Tue Feb 01, 2011 2:40 pm Post subject:

There's a hump the brake line goes over between the modulator and the calipers where air can get trapped. What I do is remove the calipers, throw a string over a garage rafter and then suspend the calipers as high as possible to let the air bleed up to the calipers. Then I use a MightyVac to suck really hard and pump the lever. When you pump the lever it will squirt so put the cover on or a paper towel over it.

To get rid of any air between the master cylinder and ABS turn the handlebars all of the way to the left and slowly pump a few times. Depending upon the angle of your throttle perch you may want to loosen it's clamp and rotate it so that the hole on the top of the master cylinder is the highest point in order to let air escape.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

slipperyox · Posted: Tue Feb 01, 2011 5:18 pm Post subject:

Thanks for replies, still not working.

The brakes were perfect prior to changing the metal line.

I thought by pushing fluid through the caliper nipples Embarassed

it would push all the air out with it?

Seriously considering a box of matches Twisted Evil

I'm handy with a tool, but this has got me
_________________
Luck is when planning and opportunity meet

Flying Duck · Posted: Tue Feb 01, 2011 5:49 pm Post subject:

Did you try raising the calipers?

Brake fluid is a liquid. It can't push air over the hump unless it's moving very fast.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

slipperyox · Posted: Wed Feb 02, 2011 4:45 am Post subject:

I'll try the caliper thing this evening, thanks
_________________
Luck is when planning and opportunity meet

Rafal · Posted: Wed Feb 02, 2011 7:16 am Post subject:

Hello!
Have you tried this:
http://www.k11og.org/forum/viewtopic.php?t=9690 ?

Best regards,
_________________
Rafal
K1100RS is a real beast (in Marrakesh Red)
K75S is a real beauty - she has gone Sad

, but not to far Smile

.

DaveVoorhis

slipperyox · Posted: Wed Feb 02, 2011 4:38 pm Post subject:

slipperyox · Posted: Wed Feb 02, 2011 7:35 pm Post subject:

ok update.

Removed master line to abs (at abs) capped line and lever was rock solid, so not the master or rubber hose.
Held calipers up in the air and bled again. spent 30 mins at this.
removed caliper line to abs (at abs ) and backflushed.
rebled whole system again and again and again.

Brakes still bad, though uesable around town.

Beats me. Going to get an oxygen sensor from work and analyse fluid for dissolved air Idea

_________________
Luck is when planning and opportunity meet

Stoked Steve · Posted: Wed Feb 02, 2011 8:38 pm Post subject:

No one has mentioned it, but have you loosened the clamping screw on the MC/kill switch assembly and rotated it upward so it is the highest point? I got lots of air bubbbles out when I did that.

Edit: Oh, just re-read your last post and I see that all is tight between the M/C and the ABS, so my suggestion above wouldn't help further down the line.
_________________
Steve
Virginia Beach, VA
93 K1100RS Mystic Red SOLD
12 Suzuki DL650A VStrom

merlin geikie · Posted: Thu Feb 03, 2011 5:09 am Post subject:

Have you got the caliper pistons fully retracted ie pushed home into the caliper bodies FULLY, as air can be trapped here Cool

Hang in there you will get it Wink

Rafal · Posted: Thu Feb 03, 2011 5:16 am Post subject:

merlin geikie · Posted: Thu Feb 03, 2011 5:25 am Post subject:

Rafal clearly knows the system very very well but Slipperyox was inside the calipers by the look of it....

Rafal · Posted: Thu Feb 03, 2011 5:49 am Post subject:

Glen · Joined: 06 Jan 2011 Posts: 2 Location: Newcastle, Australia

Hi There.

Had a similar problem recently.

I changed fluid in the brakes after doing some front end work.

I spent a whole weekend trying to bleed the brakes and felt like a real useless tool for failing.

The end result was the brakes stayed partially ON all the time.

I sucked in the pride and took the bike to my local BMW shop and the young mechanics not used to seeing a K11 failed at finding the problem also.

Ok, i didn't feel so useless anymore but still no fix yet.

The shop presented the bike to their Guru and he found a partially collapsed brake hose from the master cylinder to the the frame mount.

Made a new hose and problem fixed.

All i know is that the problem doesn't make sense and is really hard to check for

552255 · Posted: Thu Feb 03, 2011 12:04 pm Post subject:

May have been mentioned already, but once i had bled at both calipers and abs unit, i rotated front master cylinder on handlebar....so little hole is raised, and all kinds of bubbles came out.

I had to replace that same hose as well.

Bleeding isn't fun.
_________________
1997 K1100LT-SE
1996 K1100RS-SE
"Black & Silver Duo"
Lincoln, NE

slipperyox · Posted: Thu Feb 03, 2011 12:48 pm Post subject:

Thanks for replies. as the lever is rock hard when the line at the abs was plugged, it means the issue is from the calipers to the abs.

I'm hoping it will cure itself somehow.
_________________
Luck is when planning and opportunity meet

DaveVoorhis · Posted: Thu Feb 03, 2011 3:01 pm Post subject: