Bleeding/changing brake fluids

Hi

I have a 2003 ABS R1150GS on which I want to change the brake fluids but I having a problem doing so and would appreciate some help/advice.

This is the first bike I have owned with an ABS system, yet it is/was my understanding that unless you wanted to change the brake fluid within the ABS module that you could ignore it and just change/bleed the brake fluids as you would with any non ABS bike?

To that effect I removed the master cylinder cover, fitted a drain tube to the left/nearside caliper nipple and proceeded to try and pump the brake fluid from the caliper/brake line. This proved very difficult and whilst brake fluid was being removed very little was being drained form the master cylinder?

I then connected the drain tube to the right/offside caliper nipple but in this case mostly only air came out, but still the master cylinder remained more or less full?

What seems to have happened is that the brake fluids have be drained out of both the front brake lines and calipers but nothing is draining down from the master cylinder, consequently I now have no functioning front brakes as I cannot get any fluid from the master cylinder into the front brake lines.

Clearly something is amiss and I suspect that this is a procedure error in the way I have assumed you can change the brake fluids and that you cannot simply ignore the ABS module?

Have tried to find an online video of how it should be done but cannot find one that covers the ABS module fitted to my bike only those with the separate reservoirs and the 6 separate nipples you also have to bleed?

So can somebody advise where I am going wrong and what is the correct procedure to change the brake fluids? Is the some clear written documentation that covers how to do it or an appropriate video?

Thanks

IIRC the 1150s effectively have two circuits. Master cylinder to ABS unit, and ABS unit to caliper. What you have done is drained the ABS unit.

I stand to be corrected on this as it's a long time since i've worked on an 1150.

cookie said:

IIRC the 1150s effectively have two circuits. Master cylinder to ABS unit, and ABS unit to caliper. What you have done is drained the ABS unit.

I stand to be corrected on this as it's a long time since i've worked on an 1150.

Click to expand...

Thanks for the reply. It would appear from what you have advise that is probably what I have done!

So the question now for me is how do I drain the Master cylinder to ABS unit and then re-fill the whole circuit, master cylinder to ABS and ABS to calipers?

You have ABS servo- a unique system and completely different to an ABS only system… what you’ve done is empty the servo/abs modulator, which has its own reservoirs. You remove the fuel tank and bleed the separate front and rear servo abs unit from the calipers, then you bleed the master cylinders from the servo unit, you also have to bleed the servo unit.. you’ll see the six bleed nipples on the servo unit, bleed in the correct order. Your unit is now full of air, best of luck, at least by switching on the ignition when bleeding you can use the servo pump to make life easier.

Take the time to read this……It’s long winded, but thorough.

It will help you understand the servicing of the Intergral Anti Lock Braking (iabs). You don’t have to follow all of it, and you don’t need any special tools.

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

Ian J Hartley said:

Take the time to read this……It’s long winded, but thorough.

It will help you understand the servicing of the Intergral Anti Lock Braking (iabs). You don’t have to follow all of it, and you don’t need any special tools.

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

Click to expand...

Thanks for the replies.

However, this R1150 GS does not have the 6 separate nipples or the sperate reservoirs. It has the one shown on this link: https://www.manualslib.com/manual/884258/Bmw-R-1150-Gs.html?page=40#manual

But there is not sufficient detail to explain how I get fluid from master cylinder to ASB and into the calipers.

asprint said:

Thanks for the replies.

However, this R1150 GS does not have the 6 separate nipples or the sperate reservoirs. It has the one shown on this link: https://www.manualslib.com/manual/884258/Bmw-R-1150-Gs.html?page=40#manual

But there is not sufficient detail to explain how I get fluid from master cylinder to ASB and into the calipers.

Click to expand...

Right then, now that we have established that your bike has ABS2 then bleeding the brakes is relatively straight forward. As there is a direct fluid connection between the master cylinders and the brake callipers via the ABS unit. The two bleed nipples on top of the ABS unit is to bleed any air out of the system which may be in the ABS unit.

If you are unable to achieve conventional brake bleeding, then clearly you have a problem, one likely cause could be collapsed brake hoses assuming your hoses are original fit. Disconnect the line from the master cylinder to the ABS module and see if you have a blockage.

Ian J Hartley said:

Right then, now that we have established that your bike has ABS2 then bleeding the brakes is relatively straight forward. As there is a direct fluid connection between the master cylinders and the brake callipers via the ABS unit. The two bleed nipples on top of the ABS unit is to bleed any air out of the system which may be in the ABS unit.

If you are unable to achieve conventional brake bleeding, then clearly you have a problem, one likely cause could be collapsed brake hoses assuming your hoses are original fit. Disconnect the line from the master cylinder to the ABS module and see if you have a blockage.

Click to expand...

Thanks for advising which ABS module is fitted, ABS2, I take it that the other version would be ABS1?

I will need to investigate a bit more because as you have indicated, which were my own thoughts, it should be a fairly straight forward process, which clearly it is not at the moment.