Brakes and ABS

The basic braking system is common to the range but the ABS system is different between the CS, GS, Dakar and G650GS.The basic differences are set out below. Further information will be added as it becomes available.

Fault finding procedures for ABS are not well documented. The ABS dash lamp can indicate error messages but the meanings are unknown. The most common fault is scuffed or damaged sensor cabling so start with checking the cabling. There should be 1v AC output from the sensors when a wheel is spinning.

Calipers, Master Cylinders and Brake Lines
The components are all Brembo Parts pdf
Front Caliper - PF30-32 , Master Cylinder 13mm
Rear Caliper - PF34B , Master Cylinder 11mm
Brake Pads Brake Pad Info pdf    Brake Line Parts Brake Line Info pdf
Brembo Part No's

Brembo part numbers can be specific to the OEM, so the same part may have multiple part numbers but be the same part. The rear master cylinder with BMW cast into the alloy is typical. The part No is 110.4362.41 The same part without BMW stamped on it is 10.4776.50 which is listed to fit Ducati, Aprilia, Laverda and Moto Guzzi models. It is worth looking around, the price differential can be significant. Gowanloch supply many Brembo Parts for Ducati.

Repair Kits

Caliper and master cylinder repair kits may be seal kits or complete piston and seal kits. Check before buying. It can be better to buy complete Brembo seal/piston kits for other makes/models with the same calipers/MCs.

Rear Disk

The shallow head rear disk mounting bolts should be considered a use once item. They are thread locked and can shear on removal. When removing the disk application of heat to release the thread lock is recommended.

Brake Lines

The OEM brake hoses perish and break up internally blocking fluid lines, master cylinders and possibly ABS. Check hoses periodically and replace where perished. See the brake line info pdf above for Part Nos and lengths

1/ The master cylinders can corrode and it may be better to replace them not rebuild.
2/ The G650GS is fitted with brake bleed check valves. Bleed screws may be needed. pdf
3/ Normal brake bleed procedures can be used on the G650 with ABS unlike the F650GS.
4/ There are errors in the BMW wiring diagrams for ABS socket pinouts. Be warned.
5/ Brembo Front and Rear Caliper rebuild procedures. Brembo Caliper Rebuild pdf
6/ Rear Caliper and Master Cylinder Rebuild procedures from forum threads Rebuild pdf
7/ Rear Caliper and Master Cylinder fittings are 10x1 mm (see on line fiche)
8/ Wheel Sensors are Bosch, technical info and Part No's are in the pdf Sensor Info pdf
9/ Ensure Sensor gaps are adjusted to between 0.1 and 1 mm on front and rear wheels

Brake Lamp Operation

There are wiring differences for the brake lamp between ABS, non ABS models and the ABS types. Where ABS is fitted the input circuit to the ABS system results in a voltage at the lamp when the brakes are not operated and leads to confusion in fault finding. The diagram here shows the wiring differences between the variants in wiring and provides some simple fault finding test procedures. Brake Lamp Wiring pdf

Brake Lamp Switches

The switches are simple micro switches which cant be repaired. Check with a multimeter, replace if faulty. Bending of the rear switch actuator lever is critical

ABS Variants

The majority of parts are specific to the CS. The front sensor ring is common with the GS.
The pressure modulator looks the same as the GS but is a different Part No.

F650GS & Dakar

Single & dual spark ABS parts are the same. The GS & Dakar are different modulator Part No's. The on/off switch & dash lamp wiring of the GS & Dakar is different & ABS sensitivity is likely to be changed. 00-01 models have unbalanced shielded sensor leads 02+ cabling is balanced, presumably for improved noise immunity.


The ABS pressure modulator is the ABS8M system and is a completely different unit to the F650GS with different mounts. Only the sensor rings are common to the f650gs.
The technical details are in the pdfs below.

Bleeding the ABS8M is the same as a non ABS system.

Parts CS/650GS
ABS Parts List pdf

ABS Technical Info
Technical info pdf
F650GS & Dakar
ABS Pinout pdf

ABS Error Codes
Error Codes pdf
G650GS & Sertao
ABS Pinout pdf

Speed Sensor Info
Wheel Sensor pdf
ABS Repair

Injectronics in Australia repair K1300S & R1200GS modules, possibly others.

ABS Removal &
Dash Replacement
ABS removal and/or dash assembly replacement is not straight forward. There are discussions on forums with regard to both subjects and are worth reading. The dash lamp requires circuitry to turn off the ABS lamp or globe removal.
There is a path to earth from the battery through the ABS socket, when isolating the battery or jump starting an ABS model it is advisable to disconnect the ABS.