Bleeding k100 ABS / Replacing brake lines

[WHITE91K100RS]

Hey fellow brickheads,


I have a 1991 K100rs  4V with ABSII. Tried to use a brake bleeder with my air compressor to bleed the brakes but wasn't successful getting the old brake juice out, and I busted the rear brake hose in the process (part 34 32 2 311 325 pictured below).


Anyone here have any advice on proper bleeding and service for the ABSII unit? Everything I read says it needs to be done by dealer... Furthermore, any suggestions for replacement brake hoses other than OEM? Thanks for the input.

[alexis291]

I echo what Johnny said. I use a vac pump and it worked fine for me, using the frankenduck procedure in the link.
Take note about adjustment of the actuating rod between cylinder and pedal though. I took out too much slack on mine and my brake ended up binding. I had a very nasty moment when I stopped and found that the rear calliper was on fire!
I am using Goodridge braided hoses.


Sent from my iPhone using Tapatalk

[Filmcamera]

I agree that you probably have ABS1 - I have a 1991 K100RS and mine is ABS 1


I have bled my brakes (eventually) and also swapped all the hoses for Spiegler Stainless


It is a slow and laborious process - you will need lots of extra brake fluid because you will need to pump tons of fluid through but it does work.

[WHITE91K100RS]

I was afraid that replacing all the brake lines was going to be recommendation... makes sense being that they are 26 years old. Sounds like a chore though


Thanks for linking the stainless steel lines Johnny

[jakgieger]

I have a 1911 K100RS and mine is ABS 1

Wow, that  :2thumbup: IS an early one....

[bizzaro]

I bled my brakes manually on my 94 ABS II and I went through about 3/4 of a quart of DOT 4. This takes a lot of patience and persistence doing it the old fashioned way. I got sick of it. My brakes are a little "hard" but they work.  I will use a vacuum pump next time.  And Get two quarts of Dot 4!
 
WHITE91K100RS:"I have a 1991 K100rs  4V with ABSII."

While the first generation of BMW Motorrad ABS already offered a high level of additional safety by ensuring lateral grip on vehement straight-ahead braking manoeuvrings, even on slippery surfaces or with abrupt changes in friction coefficient, BMW ABS II introduced in autumn 1993 improved the range of performance even further.

It must be true...................I read it on the internet!

[The Mighty Gryphon]

BMW shop manual calls for pressure bleeding so after screwing around the old school way I sprung for one of these.

http://www.ebay.com/itm/Gunson-G4062-Eezibleed-Kit-/311007746117?hash=item4869819845:g:0tsAAOxydlFS6iQ6

I used to use a vacuum bleeder, but it sucked air in at the bleeder, and I always suspected it pulled air at the master cylinder as well.  I'm hoping the pressure will push the air, if any, out instead of sucking more into the system.

Downside is that the Gunsen requires that I make a new cover for the front master cylinder to make the connection.

[Martin]

I made a lid for the front master cylinder out of a piece if 6mm aluminium scrap, I can post a picture if needed. I have since reverted back to vacuum bleeding due to the messy nature of pressure bleeding. After 20 years + of faithful service my bleeder jar developed a leak around the lid.  :dunno  I found a Nescafe jar about the same size, made up a new one. Used it once to bleed the Chinese master cylinder and proceeded to knock it off the bench.  :dunno2: Last week while on my Saturday ride dropped into a dump recycle shop and found a heap of Nescafe jars so I bought two one for a spare for the exorbitant price of 20 cents.  :2thumbup:

[The Mighty Gryphon]

Martin, I have to make two covers for the different front master cylinders on my bikes.  I have some 1/4" ABS(not anti lock brakes, but acrylinitrilebutadrinestyrene plastic alloy)sheet, some rubber sheet and an idea of what I want to make.  Only thing missing is an urgent need to bleeed the brakes before next Fall.

[Martin]

 Gryph acrylinitrilebutadrinestyrene say that fast six times.  :2thumbup:

[Filmcamera]

Heck say it once after doing a three beer maintenance job on your K bike

[Martin]

Try and say it if you have dentures.  :hehehe

[The Mighty Gryphon]

Trust me, it's a lot easier to say then to spell.  I know I didn't get it right, but my eyes get blurry when I try to read what I typed.

Here's the correct spelling: Acrylonitrile butadiene styrene

[WHITE91K100RS]

Bought frony and back brakelines from spieglers.


Any words of advice/wisdom on best practices when replacing front and rear brake lines on ABS bike?


Thanks all :clap:

[Filmcamera]

The Spieglers are fairly short and very stiff, they are hardly flexible at all.  You will  find that this makes taking the front calipers off impossible with the hoses connected in the future, the only drawback I have found with them so far...


The kit comes with their own Spiegler Banjo Bolts. Be very careful with them, they are super soft.  Use the tool they send to get the line shaped right then carefully tighten the banjo, they thread super easily... (ask me how I know  :yow )


I swapped the hoses pretty much in order. Starting at the brake lever and working my way down the bike.  Make sure that where the hoses connect to the caliper there is still room to undo the bleed nipple.


Lastly on the rear brake the hose that goes into the ABS from the MC was different on mine to the rest of the hoses, it does not connect with a  banjo but instead is a male threaded hose that goes straight into the MC.

That is about all I can think of.


Good luck.

[K1300S]

replacing the soft lines is not hard.

dang....you guys using a full quart of fluid and saying bleeding the brakes is time consuming must be doing it wrong....  the whole system holds maybe a pint.

suck all the old fluid out of the resevoir with a turkey baster.
use screw driver or pliers to pry brake pads back into calipers to compress the pistons
suck out the fluid in reservoir again
fill will new fluid
attach catch bottle to caliper to be bled
open and close the caliper bleed screw with one hand while pumping brake lever with other hand.  repeat until reservoir is almost empty.
refill reservoir.
repeat bleeding
refill reservoir
move on to next caliper.
repeat.

for abs, add one reservoir full of bleeding at the abs pump bleed screw BEFORE doing the calipers on that end of the bike.

done.  30min if you go slow.  half a quart of brake fluid used....max.  no mess.