K11 Owners Group

joeangi · Posted: Tue Jan 27, 2009 11:24 pm Post subject: Brake problems

Worked on the bike tonight. Figured I would get the rear brake sorted out. I opened the master cylinder and it was empty!! I filled it with fresh fluid got about 2 bubbles. I then bled the ABS modulator ( the front bleed screw) those Germans, crafty front bleeder for the rear brakes. Anyway, after about 30 vacuum pulls I was basically getting nothing. I switched to the rear caliper and same thing....after about 30 pulls, I had a total of 1/2 oz of brake fluid. That also included "pumping" the rear brake pedal as well. I do have the battery and motronic unit out, does the bike need to be powered to bleed it properly? What am I doing wrong, or what should I check next. Thanks for the help

Phil Marvin · Posted: Wed Jan 28, 2009 12:00 am Post subject:

Hi, Joe,
The battery does not have to be installed to bleed the brakes properly. I have never had to bleed any air out of the system, only old fluid when I change brake fluid. I might obtain and use one of the suction devices if I were having trouble getting fluid throughout the system, but there are many on this forum more mechanically inclined than I. Maybe they will chime in.
Ride Safe,
_________________
Ride Safe,
Phil Marvin in El Paso, TX
'94 K75A/3
'95 K75RTP

Scott_Anderson · Posted: Wed Jan 28, 2009 12:20 am Post subject:

In the process of my clutch spline lube I removed my abs system and all of the rear brake tubing, master cyl, caliper, etc...

When I reassemled everything I just filled at the master container, bled to the abs, then bled to the caliper.

I wasn't using a "hand pump" though. I happen to have an old retired medical suction unit, so it didn't take long. But I have to be careful not to suck the system dry with it though.

***CAUTION***
DO NOT adjust/change the adjustment screw at the foot pedal to try and get more travel of the lever. You can cause the brake pads not to release and potentialy start a fire.
***CAUTION***

edit
You can also do it the very old fashioned way. Fill the master cyl, slowly pump up the pressure and then open the bleeder, close the bleeder, repeat.
I did it this way the 1st time until I aquired my power unit.

Stay with DOT4 brake fluid, and cover everything. The brake fluid will eat the paint.
_________________
Ride safe.

1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

Jim · Posted: Wed Jan 28, 2009 12:41 am Post subject:

Joe - you can also open the bleeders and let gravity do the work - takes longer, but it works...
_________________
Jim
1997 K1100LTSE 94,000 - still has gremlins!
1995 R100RT Classic 16,650 crashed - repaired!
1992 K75RTP 46,000

"We shall not all die, but we shall all be changed."

joeangi · Posted: Wed Jan 28, 2009 8:31 am Post subject:

Thanks for the suggestions, but I think that the system has "lost its prime" it has been laid up for at least 2 years. I should have been able to pull fluid out of the pump...or the caliper. Is there a way to pre-fill the pump and kinda get things going? For me to put 40-50 inches of vacuum on the bleeders, I should get some fluid. I can try to leave the bleeders open to get gravity working, but not sure that is going to do it.

joeangi · Posted: Wed Jan 28, 2009 8:33 am Post subject:

I also tried the manual "old-fashioned" way, but I get no resistance at the pedal, it did not pump anything through....Fronts are soft also, but I figured I would start with the rear.

Scott_Anderson · Posted: Wed Jan 28, 2009 8:36 am Post subject:

I suppose, if your carefull, you could diconnect all the lines and see if there is some kind of obstruction that's blocking the flow. Then as you fill start at the top and follow the fluid down the line as you assemble it.

This can be very messy though, but then you know.

If the system sat empty for too long I suppose it's possibe the the cups/plunger seals could have hardened up and won't make pressure.
_________________
Ride safe.

1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

joeangi · Posted: Wed Jan 28, 2009 8:49 am Post subject:

That what I am afraid of...

joeangi · Posted: Wed Jan 28, 2009 10:01 am Post subject:

These brakes are driving me crazy! I tried adding fluid to the abs pump, no dice. flowed all over. Then I tried one more time to bleed, not much fluid. Then I figured I would pressure fill the abs pump. I put about 3-4 oz through the abs pump, and out through the rear caliper. Then I tried bleeding again. I still am getting no draw through the master cylinder. It still is half full. The brake pedal is still soft, and of course we have no brakes....Help!

jpberens1994K1100RS · Posted: Wed Jan 28, 2009 10:32 am Post subject: brakes

Your screwed.

Complete dissassembly required at this point to figure it out. IMHO of course, I am NOT a certified mechanic.

I have NOT seen it on a BMW, but a crappy old Honda that got diplaced and sat in my garage had the interior walls of the brake lines slough off and clog up the works.
I HAVE heard it can happen to a BMW though, and I think that's what is going on with yours.

Junk in the lines which really is degraded material from the lines.
_________________
1993 K1100RS that I'd rather be riding FAST!
2014 Moto Guzzi Norge

joeangi · Posted: Wed Jan 28, 2009 1:24 pm Post subject:

Houston....we have brakes!!!! Just as I was going to tear the whole thing apart. I tried pushing the brake pads in as far as they would go to try and force some fluid backwards. Then I opened the fitting on the master cylinder to remove it, and we and "drippage" so I worked the pedal and we had "flowage" and the pads started moving. Put it all back together, re-bled everything and all is working. Yeah!

jpberens1994K1100RS · Posted: Wed Jan 28, 2009 1:40 pm Post subject: Brakes

AWESOME!!!!! Very Happy

But, sorry to rain on the parade, please keep a CLOSE eye on things.
Dripping, sponginess ect.

Stay safe!
_________________
1993 K1100RS that I'd rather be riding FAST!
2014 Moto Guzzi Norge

joeangi · Posted: Wed Jan 28, 2009 3:37 pm Post subject:

Well, I will keep an eye on things....but it was frustrating