Brake bleeding

[c13pep]

My return to BMW is in the form of a 2004 R1150RT that has been stood for 5 years but which I will return to its former glory, by hook or by crook. My intention is to replace all fluids as a start but the ABS brakes look a tad complicated, can I do a fluid change on the brakes as a diy job or is it a dealer job. I am confident in my mechanical skills but when the Haynes manual is saying that the ABS is too complicated for them to devote a chapter to then alarm bells start to ring
CHRIS

[Mike D]

Have a read of the following:

http://users.rcn.com/dehager/service/service_abs3.pdf

It also pays to have a GS-911 diagnostic tool. This has a function to test whether you have bled all the air out of the system.


Mike

[c13pep]

Thanks for the link Mike it looks to be quite involved but after reading it a few times it makes more sense and is not as daunting as I first thought, also the instructions are really clear
I have found the wire to the front ABS sensor has been rubbing on the wheel so does anyone know the routing of this wire as it just doesn`t look right, mine is tie wrapped to the brake pipe and is then the spare wire is bundled up besides its connector under the right side of the tank
CHRIS

[bazzzer]

Its actually quite easy once you've done it once, just a lot of connecting / disconnecting at the ABS pump to
bleed the three nipples. Suggest getting the special funnel for the ABS to wheel circuits, with this takes about 15 seconds to bleed them ! If you are near you could always borrow mine.

[c13pep]

Thanks for the offer Bazzer but I`m in Yorkshire so not exactly next door, however I wish to change the fluid in the entire system and the link that Mike provided looks to be written as an idiots guide so I`m ideally suited for that.

CHRIS

[sykospain]

The esteemed Mr. Hager's exhaustive how-to from many years ago is a first-class guide to the complicated job of servicing ABS-equipped bikes' brakes.

I'd take issue with only one aspect of it though, and that concerns caliper pistons cleaning.

These calipers sit in the direct blast of dirt and weather as you ride along, and as the pads wear, slightly more of each piston surface emerges from its seal, thus becoming cruddied-up to various degrees.

I think it's very important NOT to push any of the pistons back into the caliper body past their seal, in order to extract the pads or do anything else, until the whole circular surface of each piston has been restored to factory brightness and shine with a car-finisher's ScotchBrite rubbing cloth. Many BMW / Brembo caliper pistons are chrome-plated and should be nice'n'shiny. Pushing cruddied-up pistons back into the caliper body before cleaning their outer surface can compromise the fluid seal.

As seen elsewhere on the excellent 'ADVRider' forum, the cleaning procedure detailed by member 'cyclerob' is the best way to achieve these pistons' clean brightness.

Using soapy water and a stiff toothbrush to clean up all the nooks and crannies of the caliper casting is the way to go, and where the section of each piston circumference right in the corner by the caliper casting is inaccessible, using the recommended piston removal pliers to turn the piston to reveal the hidden mucky bit is the ideal. This set of pliers grasps the inside diameter of the piston NOT THE OUTSIDE, thus avoiding marks on the sealant-to-metal surface. Remember, the piston is in the shape of a small coffee cup.

Also, a smear of rubber / nitrile seal-friendly oil on the cleaned-up surface and working the pistons in-and-out several times under fluid pressure will restore superbly silky hand and foot lever operation.

Manual as opposed to powered vacuum bleeding often doesn't shift the mucky DOT4 hidden inside the caliper body, so many enthusiastic caliper cleaners with plenty of time on their hands disconnect the caliper from its fluid line and push out all the pistons completely, one-by-one, with the help of a compressed-air line, to polish them up properly and to discard any remnants of crappy fluid hiding inside the caliper body. This of course requires a complete new flush and bleed.

Only saying....

AL in s.e. Spain

[c13pep]

Many thanks for that SYKO couldn`t agree more and I do subscribe to the last paragraph with regard to completely stripping each caliper and getting rid of ALL the old fluid although I wouldn`t class myself as having time on my hands rather I like to do it thoroughly and there are only 3 of them.
CHRIS

[sykospain]

In a conversation on the UKGSer forum, I was glad of a really useful tip from the esteemed member "Steptoe", that's Neil who runs the GS Shop in London SW15, UK, specialising in boxer bike maintenance issues. www.gsshop.biz

It concerns not so much brake caliper cleaning as clutch hydraulics bleeding, but has some relevance here.

He says 'before re-attaching and then bleeding the slave cylinder, push in fully the piston and secure it in that position with a G-clamp to make sure there's no chance of trapped air in the cylinder. Then do the bleed routine."

So I presume that applying this idea to the four-piston brake caliper, pushing in all four thoroughly cleaned pistons and securing them in that position with a dummy wooden pad might similarly expel trapped air inside the caliper which might otherwise evade normal bleeding. Thus obviating the need to detach the brake line from the caliper to check there's no air or old fluid left in there.

Might work....

[c13pep]

That`s a really useful suggestion would you pass on my gratitude to "Steptoe", it also proves that your never too old to learn.
CHRIS