B340414

5/4/2021
34 04 14_Diagnosis of Compound Brake System Complaints in M Vehicles
SIB 34 04 14
Diagnosis of Compound Brake System Complaints in M Vehicles
2021-04-15
This Service Information Bulletin (Revision 7) replaces SI B34 04 14 dated July 2018.
What’s New:
Additional models added
MODEL
E46 (M3 Coupe,
Convertible)
E82 (1 Series M
Coupe)
E92 (M3 Coupe)
F12 (M6 Convertible)
F83 (M4 Convertible)
F90 (M5 Sedan)
E60 (M5 Sedan)
E63 (M6 Coupe)
E64 (M6 Convertible)
E85 (M Roadster)
E86 (M Coupe)
E90 (M3 Sedan)
E93 (M3 Convertible)
F13 (M6 Coupe)
F85 (X5 M)
F95 (X5 M Sports
Activity Vehicle )
F06 (M6 Gran Coupe)
F80 (M3 Sedan)
F86 (X6 M)
F96 (X6 M Sports
Activity Coupe)
F10 (M5 Sedan)
F82 (M4 Coupe)
F87 (M2 Coupe)
F97 (X3 M Sports
Activity Vehicle)
F98 (X4 M Sports
Activity Coupe)
SITUATION
The customer’s complaints may include:
1. Visible cracks in the brake discs can be noticed through the wheel opening or during service.
2. There are temporary vibrations or steering wheel torsional vibrations during braking.
3. After high brake loads, running noises can be heard when applying the brakes.
INFORMATION
1. Visible cracks are caused by high thermal
stresses during rapid heating and cooling of
the brake discs. Braking from high speed with
cold brake components (less than 212 degrees
F) increases the likelihood of cracks to form.
These hairline surface cracks are usually
spread over the entire brake disc friction area,
and have no negative influence on the
durability or braking performance.
The rotors should not be replaced only for
their appearance reasons.
When performing routine service on the brake system (pad replacement due to wear), the brake discs
should be replaced if surface cracks are found to be greater than 13 mm, or if the brake disc thickness is
below the minimum thickness.
Always replace brake discs in pairs (per axle). Install new brake pads when replacing discs. By doing this,
the service life of the friction pad surface is increased, and an even material loss is ensured.
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5/4/2021
34 04 14_Diagnosis of Compound Brake System Complaints in M Vehicles
2. Vibrations and/or steering wheel torsional vibrations during braking are caused by applying the
brakes on discs with minimal to heavy corrosion. These vibrations are most noticeable when braking
from high speeds with cold brake components (less than 212 degrees F), and will diminish with
normal everyday operation. Parts replacement is not required.
3. After high brake loads, running noises
can be heard when applying the brakes,
and may also be heard to a limited extent
after the brakes are released (See the note
in the Owner's Manual).
These noises are reduced during normal
everyday operation, due to further erosion
of the brake pad friction lining.
Visible surface cracks or crater-like
recesses on the brake pad surface are
caused by a minor difference in the
material of the pad lining, which will
decrease with further operation and should
not be replaced due to their appearance.
WARRANTY INFORMATION
Not applicable
QUESTIONS REGARDING THIS BULLETIN
Technical inquiries
Warranty inquiries
Parts inquiries
Submit feedback at the top of this bulletin
Submit an IDS ticket to the Warranty Department or use
the chat available in the Warranty Documentation Portal
Submit an IDS ticket to the Parts Department
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