Jump to content

I hate to ask: Brake Bleeding on a R1100RT (ABS, no EVO)


Recommended Posts

My Clymer manual (R850/R1100/R1150/R1200C 1993-2004) makes the blanket statement(s), to the effect of:


"On ABS models, have the brake's bled by your BMW service dealer...", and "The ABS brake system must be bled with a power bleeder. WARNING: Do not try to bleed the ABS brake system without the power bleeder, as it is impossible to manually purge all the air from the system. any attempt to manually bleed the system will result in an unsafe brake system."


I thought that only applied to the R1150RT EVO equipped bikes. I had thought that the R1100RT's could be bled conventionally. In fact, the BMW service manual details a conventional bleed (i.e. remove brake pads, keep caliper upright, push the piston's all the way back into the caliper, block them off so they can't move using ridiculously expensive BMW tools (p/n 34 1 500 & 34 1 520), squeeze the lever, crack the bleeder, bleed some fluid, close it, repeat..etc.). The handy IBMWR Oilhead maintenance manual seems to think manual or "Mityvac" bleeds are o.k..




a) What am I missing here in the procedures which make all ABS systems (not just EVO systems) a mandatory dealer maintenance item?


b) Can you recommended threads on this board to keep a rookie from ruining his disk brakes? I know this topic has been beat to death, but most of the threads I found in my search relate to bleeding the EVO brakes.


c) What's a "power brake bleeder"? Why does my bike require one??


d) If I bleed the brakes conventionally, i.e. adding fluid to the Master Cylinders and bleeding through the bleed screws, the fluid in the ABS unit will also be replaced, correct? Any problem with air bubbles getting trapped in the ABS unit (as I think it's mounted higher than the rear brake MC)?


My notes also include:


"Check all hoses and fittings for leaks and ensure all are tight", "measure brake pads", "test calipher to ensure it pops back easily when manually pressed in", and also check caliper guide pins for rust, polish them up if necessary, clean everything with brake cleaner, and check rubber boots for damage/cracking.


Also: If the caliphers show evidence of moisture or leakage, rebuild them with new seals, and make certain the piston and cylinders are unscored.


Hmmm..oh, yeah, rotors/disks: Check for deep radial scratches, for warping with a dial indicator, and for thickness to spec using a micrometer. They cannot be turned or resurfaced.


Also, other cautions: don't spill brake fluid on paint, use fresh DOT 4, careful not to tip handlebars when filling front MC, don't squeeze lever with brake pads out and pistons unblocked (or reservoir top off) use teflon tape around bleeder valves if they don't seem to seal up.. don't over tighten. Never use petroleum based solvents to clean system components, only brake cleaner or isopropyl alcohol.



Having read three manuals and whole bunch of bmwst threads, I'm still looking for the punch line. Why can't I bleed the brakes on a R1100RT manually?? I hate asking these questions; I know they've been covered 100 times.




PS: I know about the benefits of a Mityvac; might try it as I have three bikes to bleed (2 off road MX's). I know about speed bleeders; anything that might make my brakes bleed at an inappropriate time scares me, so I'll stick with the old fashioned bleed screws. eek.gif

Link to comment
Stan Walker



I've been flushing & bleeding my '96 RT for the last 9 years. At first I used a MityVac then later changed to a air powered vacuum pump. Works fine. The air powered unit allows me to stay at the master cylinder pouring DOT4 without having to run & pump every few seconds.


The real problem here is Clymer. They simply made that restriction up. Of the three manuals available for the 1100's, Clymer is the one I almost never open. POS in my not so humble opinion.


So in order:

a) It's not true.


b) I'm sure it's documented somewhere, but you will have to search. Maybe one of the admins will know where it's at. They are flushed/bled just like any other standard brake system. The squeeze, open valve, close valve, release will work but with some risk of damaging the master cylinder seal if it goes past it's normal travel and encounters rough areas of the bore.


c) Power brake bleeders come in two main types. The powered vacuum unit works just like the MityVac without pumping. A pressure type attaches at the master cylinder and pushes fluid through the system. Works great unless you spring a leak. Can be made cheaply from a garden spray can. And you don't really need either type. They do make the job faster!!!


d) It is possible to collect a few bubbles at the ABS unit, or so I've been told. I've yet to bleed at the ABS on the '96. If the brakes feel good when I'm done then I don't worry.



Link to comment
John Dickens

Just bleed the brakes in the conventional fashion. I've tried a couple of the more technical gadgets but in the end I use speedbleeders and just press the pedal or pump the lever. Takes about 15 minutes tops to flush through all the fluid.

Link to comment
Joe Frickin' Friday
...I use speedbleeders and just press the pedal or pump the lever.


thumbsup.gifthumbsup.gifthumbsup.gif Have tried conventional bleed, MightyVac, and SpeedBleeders. SB's rock the house; they make it an easy one-dude job. thumbsup.gif

Link to comment
Joe Frickin' Friday
d) It is possible to collect a few bubbles at the ABS unit, or so I've been told. I've yet to bleed at the ABS on the '96. If the brakes feel good when I'm done then I don't worry.


Can't remember where I heard it, but the suggestion was that the very first time you bleed the brakes on an 1100RT, it's worth bleeding at the ABS unit to purge any air that may have been in there since the bike was built; ever after that, there should be no need to purge there unless air has been introduced into the system, e.g. screwing up with a MightyVac, or installing new lines. I followed this advice, and I recall getting a few air bubbles out, not much. But yeah, should not be required to bleed the system annually at the ABS unit.

Link to comment
skinny_tom (aka boney)

Slightly related but a different bike with a similar ABS unit.


I put a longer front brake line on my F650GS to accomodate the handle bar risers. In doing so I was left with a lot of air which "got caught" in the ABS unit when I bled it. The simple solution was to take the bike out front and run it up to about 20 MPH and force the ABS to fire by applying full front brake, then re-bleed black in the garage. It works well.


While this is not "traditional" wrenching, and may not even be that safe, it is certaily effective if you run into trouble. YMMV.

Link to comment

Scott: First of all, you might want to put a big towel on top of your gas tank. Then take a flashlight and look at the underside of your front master cylinder, is all the paint flaked off? Then, with a blue Scott shop towel in hand (I love those things) look for a phillips screw on the front of the master cylinder. It holds on a cover. As you take it off, be prepared to invert the cover as there may be some fluid in it. Take a light and shine it in there. Is there fluid in that cover? Then the master cylinder needs to be rebuilt, a new one installed , or some guy in the Southwest resleeves them. I am not sure about who the guy's name is that resleeves them, maybe somebody here would post his name. When I was having my throttle cables replaced at 18k on my '98 RT the mechanic called me out to the shop and showed me the underside of the front m/c. He then took off the cover and showed me the fluid in there and gave me the bad news that obviously the prior owner had not adhered to the mandatory annual brake flush. I asked the mechanic " You mean to tell me that these darn bikes have to have their brake fluid flushed every year?" Yes, he replies. I told him it sounded more like a poorly-designed master cylinder. Hopefully, you will be able to just flush yours. Put lots of towels on the tank, (a friend to help would be great too) and don't pull the front brake lever or the rear brake lever all the way down- more like midways. Jamie or somebody wrote a post where they explained how that unused portion of the piston in there gets crudded up and acts like a cheese grater on the seal if you pull the front lever or rear pedal all the way down- in the process shredding that seal and damaging the seal. Maybe someone can add to this opinion on pulling the lever or pedal all the way through its travel on a bike if we don't know that the fluid hasn't been changed every year. Or perhaps the mity-vac route would be the way to go. Just remembered that you have to pull the right hand tupperware to access the rear master cylinder fluid resevoir, so brake fluid won't be able to drip on r/h tupperware, but put towel on center strip of tank, and front fender.

Link to comment


This topic is now archived and is closed to further replies.

  • Create New...