BMW R1200RT/R1250RT Forum

David. wrote:The BMW dealer has confirmed that the ABS unit is flushed as part of the F&R brake fluid change procedure.

This was the reply I got from Cooper BMW Sunderland in 2017 when the brake fluid was last changed before next having it done at AJ's in 2020.

Cooper Sunderland have now come up with two different answers to the same question, it'll be interesting to hear what AJ's have to say.

Our Gee wrote:ABS unit along with both front and rear circuits to be flushed at a local "independant" who talked me through the procedure.

What procedure did the local independent use, was the ABS unit activated/flushed with a GS-911 or equivalent between manual flushing of F&R brakes.

David. wrote: What procedure did the local independent use, was the ABS unit activated/flushed with a GS-911 or equivalent between manual flushing of F&R brakes.

Sorry, couldn’t really say. From memory (which is getting worse) I recall him talking about about the procedure which involved the ABS Pump over the phone when I initiated my enquiry and that he had the necessary diagnostic gizmo. I did not actually witness the job as I dropped the bike off, walked around for a couple of hours and returned to find everything completed. It will be very interesting to hear what David’s dealer has to say. Incidentally, one technicians idea of flushing the ABS pump could be different to another’s. Doing a conventional flush and bleed on an RT has the fluid going from the Front Master Cylinder to the ABS module then to the Front and Rear Calipers which one may interpret as Flushing the Module. However, without cycling the Pump, the way I see it there could be contaminated Fluid trapped in there which could cause corrosion to the delicate valve mechanisms ? .

This is the brake fluid circuit on a 2016 Wethead GS, most likely similar to that on a 2013 Camhead RT.

Found a video of a Camhead RT, https://www.youtube.com/watch?v=95aWkN30lXU&t=220s (skip to 20:45) for ABS pump.

Our Gee wrote:Doing a conventional flush and bleed on an RT has the fluid going from the Front Master Cylinder to the ABS module then to the Front and Rear Calipers which one may interpret as Flushing the Module. However, without cycling the Pump, the way I see it there could be contaminated Fluid trapped in there which could cause corrosion to the delicate valve mechanisms.

The above video would certainly seem to support this theory.

A new ABS modulator (pump) is nearly £1,500, https://www.online-parts.co.uk/bmw-bike ... nth=04#sub

At approx. £60 every 2 years, having the brake fluid changed (inc. cycling the ABS pump) would seem like a good idea to me.

I'd rather do that than deliberately try to induce a rear wheel skid or practice front end stoppies!

[quote)

At approx. £60 every 2 years, having the brake fluid changed (inc. cycling the ABS pump) would seem like a good idea to



Which brings us back to the question. Going by the apparently different procedures voiced by Dealer Technicians who is correct ?.
Looking forward to hearing what David’s Dealer has to say.

AJ's have confirmed this morning that on my 2012 Camhead, the ABS pump is not cycled during the otherwise manual brake fluid change procedure.

On bikes with "Integral" ABS, the ABS pump needs to be cycled, perhaps this is the difference between GEN I and GEN II ABS systems.

My RT is fitted with GEN II ABS.

From what I can see, bikes with servo brakes (early Hexheads) had GEN I (Integral) ABS. This was changed in 08.2006, my 2007 Hexhead didn't have servo brakes.

The word "Integral" seems to be misleading, perhaps servo and non-servo would be a better description.

PRESSURE MODULATOR INTEGRAL ABS


PRESSURE MODULATOR I-ABS GENERATION 2