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Bleeding ABSII ( -94 K11 ) front break

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    • Bleeding ABSII ( -94 K11 ) front break

      Renovated front calipers with new sealings and pistons.
      Have some challenge bleeding the breaks.
      Used the common procedure pressing the level, open the bleeding valve on caliper and closed it again before releasing the level.
      Repeated over and over again on both caliper until no air coming out. Also opened and losed the rear bleeding valve on top of the ABS unit.
      But it's still air in the system.
      Any tips? link?
    • Please bleed the ABS unit first and then the calipers.
      After that turn the handle bar to the left, press the brake lever slightly and fix it with a rubber band. Wait one night!
      "Technischer Fortschritt ist wie eine Axt in den Händen eines pathologischen Kriminellen."
      Albert Einstein
    • Brake linings lie all the time.
      Renovated the calipers front (new seals and pistons) + new breakpads.
      Bled according to many tips incl. The pistons pushed back a maximum then calipers positioned vertical following by horrisontal to start bleeding.
      First used underpressure then classic lever pressureized + open vent valve, closed vent valv, and repeated this over and over again ..... slowly getting out brake fluid as there seems to be a pressure plocking in the system.
      BTW. Bleeded the ABS unit first.
      Despite all the air seems to have come out from ABS and calipers. the handle is spongy and braking performance is minimal.
      Took the bike on a ride to activate ABS'n, the ABS lights came off .
      After repeatingly applying the brakes, I got good braking force in the front.But did not hear the famous hammering sound when ABS'n was activated from the ABS unit.
      On the gov. inspection today the brakes one the front whare applied so much that I got a remark and have to come back.
      Leaning towards it's ABS unit do not open flow between the calipers and the handle when not braking.
      I need a new ABS'enhet and if so, where to buy?
      Or could it be something else?
    • Can be that the flex break lines are to soft inside. Will get new lines.
      And that I got new break pads that have to be runned in.
      Will also check the wheel bearing and adjust the ABS pickup clearance.

      A bit riding today even if its a bit chilly, a few + above zero C, A fellow rider needs training time before test for license.

      The post was edited 1 time, last by tibbe ().

    • Attended to a 1 day trining course in handling and breaking last sunday.

      During the breaking training my front break where nearly blocked after releasing the handbreak.
      Let the bike stand for an hour and after that the handle felt like it was air in the break. PS. Applied only a bit of force to the level.

      Drove a km and stopped. Then my freind jumped on as pilon. By letting a pilon jumping on I use to apply a lot of force on the front break and after appr 500 m at appr 60 kmh. I tested the temp on the front disk one was cold and the other burned my fingertips. Put the bike on a trailer and drove home.

      Note. only one disc was hot. Secondly during the break training I felt like it was swampy rear break, nearly as when over heating the breaks during downhill riding on twisty roads, it was softer than with fresh fluid over heated and more stiff as with a year+ old fluid over heated. ( happend at Passo Stelivio and another pass in the dolomites ). Else the ABS II worked perfect, both the front and rear wheels left a very short black mark ( and sound ) by breaking hard before the ABS was engaged.
      As I will be off to scottland, belgium and france in 3 weeks should I consider swapping the ABS unit too?

      The post was edited 1 time, last by tibbe ().

    • tibbe wrote:

      During the breaking training my front break where nearly blocked after releasing the handbreak.
      That sounds like an old break-hose, wich is swollen to an inner diameter of 0 (zero) mm.
      "Technischer Fortschritt ist wie eine Axt in den Händen eines pathologischen Kriminellen."
      Albert Einstein
    • Thanks for your replies, let's hope it's only swollen break tubes as you and some other wrencher that I also respect are suggesting.
      As preperation today I removed the tank and looked for the connection between flexibale break tube from handlebar to the break line to the ABS.
      Found it under a lot of electrical wires and el-connectors near the stearing head.
      Seems to be a bit tricky to disconnect the flexible tube and replace it. Any tips?

      As the tank was removed I cleaned the electrical ground connection to the frame in the same area, and removed and cleaned all relays on the box.
      Also retigthended the battery connections ( one was a bit lose and that could give the strange behaviour of the ABS and hazard / turning lights that occured lately ).
      BTW. was a lot of fine sand from frekvent riding on gravel roads under the tank that has to be cleaned before touching the break lines, not pleased to get fine sand in the break fluid.
      PS: Beeing working on hydrauic system for driver simulator and other applications I do not appreciate any polutions in hydraulic systems.

      The post was edited 3 times, last by tibbe ().

    • Hi

      Swapped the flexible tubes last evening.
      Tools open 11 mm and 3/4" wrench + 5 mm allen key.

      The flexible tube running from handle bar head cylinder to ABS unit. was a bit tricky under the tank.
      Hidden under electric wires ( that I moved a side ) and fasten low.
      Unscrewed the plastic clamp over the break lines helps to disconnect the flexible tube from the fixed tube. Tools open 11 mm and 3/4" wrench + 5 mm allen key.
      Before taking the flex tube out, tie a strong tread to it. When instalinig the new tube tie the same tread to the new tube to make it easier to route it the same path as the old tube.
      3 x Break tubes at the fork / wheel are fairly strait forward to replace.
      NB keep the surfaces clean, dust and gravel in the system can be costly.

      The post was edited 5 times, last by tibbe ().

    • Took a test ride yesterday.
      Better control of the breaks, short fast grip on the handle even immediately activates the ABS on dry tarmac.
      No delay as before.
      Took it to the highway for a 15 min high speed ride and stopped to sense the temp of disks -- no significant temp rise
      relative ambient temp :) .
      The fault was old rubber flexible tubes not the ABS II unit.
      My comment if you have original flexible break tubes on your 15+ years old bike, consider change them to new tubes.
      Even better renovate your callipers. it's not that complicated just keep everything clean.
      On bleeding ask a fellow biker to assist you.

      Planning to make Scotland mid June then Belgium and France ( Normandy and
      Brittany ) before heading home over Germany and Denmark.
      PS living appr. 900 km north of Stockholm where 90% of the roads are gravel road :D even with a LT, IMHO it's mostly a matter of attitude AND common sense.

      The post was edited 2 times, last by tibbe ().