Claim Assessment

Name	Provider	Purpose	Expires
wire	otto-zimmermann.de	The cookie is required for secure login and the detection of spam or misuse of the website.	Session
cmnstr	otto-zimmermann.de	Stores the user's consent status for cookies.	1 year

Name	Provider	Purpose	Expires
_ga	Google	Registers a unique ID that is used to generate statistical data on how the visitor uses the website.	2 year
_gat	Google	Used by Google Analytics to limit the request rate.	1 day
_gid	Google	Registers a unique ID that is used to generate statistical data on how the visitor uses the website	1 day

Here you will find a list of the most common damage patterns of brake discs in order to enable an easier assessment and processing of complaints
If you would like to receive the damage pictures as a poster, we will be happy to send it to you: Request damage poster.

Contaminated contact surface
Symptom:
Contact surface is contaminated / smeared with grease and / or paste
Cause:
Failure to observe recommendations in ZIMMERMANN mounting instructions

Brake discs / brake drums should be assembled dry, cleanly, and metallically bright
Effect:
Grease / paste bind foreign particles which get trapped between disc / drum and hub

Coplanar assembly not possible or only possible to a limited degree

Brake disc / brake drum is assembled "lopsidedly" and runs increasingly untrue with increased mileage

Axial run-out caused by assembly can be checked on the vehicle itself, without the need for a test drive, by using a dial gauge / micrometer gauge and magnetic stand!

Steering wheel wobble / judder after approx. 1,500 – 5,000 km
Pressure marks and corrosion
Symptom:

Contact surface shows pressure marks and is corroded in parts

Cause:
Contact surface of wheel hub has not been cleaned at all or only insufficiently

Failure to observe recommendations in ZIMMERMANN mounting instructions

Brake discs / brake drums should be assembled dry, cleanly, and metallically bright
Effect:
Dirt and / or rust particles have become trapped between brake disc / brake drum and hub

Coplanar assembly not possible or only possible to a limited degree

Brake disc / brake drum is assembled "lopsidedly” and runs increasingly untrue with increased mileage

Axial run-out caused by assembly can be checked on the vehicle itself, without the need for a test drive, by using a dial gauge / micrometer gauge and magnetic stand!

Steering wheel wobble / judder after approx. 1,500 – 5,000 km
Torque and tightening sequence
Symptom:
The contact surface is cracked in the vicinity of the hole(s)
Cause:
The wheel bolts / wheel nuts have been tightened with excessive torque and / or in the incorrect order

Failure to observe vehicle manufacturer’s instructions

Failure to observe recommendations in ZIMMERMANN mounting instructions
Effect:
Coplanar assembly not possible or only possible to a limited degree

Brake disc / brake drum is assembled "lopsidedly” and runs untrue immediately after assembly

Axial run-out caused by assembly can be checked on the vehicle itself, without the need for a test drive, by using a dial gauge / micrometer gauge and magnetic stand!

Deformation of contact surface (even if no cracks are visible!)
Hub run-out
Symptom:
Asymmetrical wear of brake friction faces

Blue-black hot spots
Cause:
Functional axes of brake disc and caliper are out of alignment

Wheel hub is mounted off straight in relation to the caliper

Axial run-out caused by assembly can be checked on the vehicle itself, without the need for a test drive, by using a dial gauge / micrometer gauge and magnetic stand!
Effect:
Brake pedal vibration / judder

Steering wheel wobble

Brake fade

Wear limit reached prematurely

Partial thermal overload due to constant grinding of friction ring on pad
Running-in phase
Symptom:
Friction surface and / or hub showing the so-called annealing colors (off-white to grey)
Cause:
Running-in phase too short

Violent braking / panic stops carried out during running-in phase

Use of incorrect pads (friction coefficient, composition, quality)
Effect:
Brake pedal vibration

Steering wheel wobble

Brake fade

Due to thermal overload

Brake disc anneals, there can be structural transformations, alteration of the mechanical properties of the cast material
Intensive use
Symptom:
The brake friction faces are showing blue-black so-called hot spots.

Net-like hairline cracks have developed into larger radial heat cracks mainly in the centre of the friction ring.
Cause:
Running-in phase too short

Violent braking / panic stops carried out during running-in phase

Use of incorrect pads (friction factor, composition, quality)

Individual vehicle handling
Effect:
Brake pedal vibration

Steering wheel wobble

Brake fade

Due to thermal and / or mechanical overload: the brake disc anneals and / or there is structural transformation, alteration of the mechanical properties of the cast material and / or friction surface / brake friction faces can crack through
Wear limit
Symptom:

The brake friction faces are unduly worn; there is a clear difference in thickness between
the contact area of the pads and the original thickness of the friction surface

Cause:
There is a substantial shortfall below the prescribed wear limit

Failure to observe recommendations in ZIMMERMANN mounting instructions

Wear limit is stamped into the ouside diameter of the brake surface or onto the hub
Effect:
Steering wheel wobble

Brake fade: "long" brake pedal travel

Due to thermal and / or mechanical overload: the brake disc anneals and / or there is structural transformation, alteration of the mechanical properties of the cast material and / or friction ring can break away from the hub
Thermal Overload
Symptom:
The brake friction faces are showing blue-black so-called hot spots

Net-like hairline cracks have developed into larger radial heat cracks
Cause:
Thermal overload

Individual vehicle handling
Effect:
Brake pedal vibration

Steering wheel wobble

Brake fade

Noise generation (humming, droning, grating)

Due to thermal and / or mechanical overload: the brake disc anneals and / or there is structural transformation, alteration of the mechanical properties of the cast material and / or friction surface / brake friction faces can crack through
Periods of non-use
Symptom:
On the braking area there are layers of corrosion, some of them thick, peeling off the friction ring.
Cause:
The vehicle concerned was not in use for a relatively long period (garaged vehicle / stored vehicle)

The vehicle concerned was not used for relatively long periods after being driven in damp / wet conditions (water damage)
Effect:
Brake pedal vibration / judder

Steering wheel wobble / shimmy

Brake fade: Brake pedal becomes "hard"

Noise generation (humming, droning, grating)

When started up again the friction ring and pads are badly damaged by the extremely hard scale particles becoming detached

Fragments of disc and pad material are torn out
Mal function of parking brake
Symptom:
The brake disc has radial cracks in the area of the parking brake diameter (hand brake), some of which continue across the thermal insulation channel into the braking area

The parking brake area diameter (hand brake), groove for thermal insulation and braking area are exhibiting the so-called annealing colors
Cause:
The vehicle was driven with the parking brake on (applied) for a relatively long period and then also stopped with the parking brake applied

The mechanics of the parking brake and / or the cables are sluggish or not serviceable
Effect:
Due to thermal and / or mechanical overload:
the brake disc anneals and / or there is structural transformation, alteration of the mechanical properties of the cast material and / or friction surface / brake friction faces and hub can crack through

Acute noise generation (humming, droning, knocking) when braking

Acute noise generation (grinding, rubbing, rattling) when applying the parking brake
Glazed brake pads / friction surface
Symptom:
Particles of the friction material have worked / „burnt“ into the braking area

Shiny surface on brake friction faces
Cause:
Inferior pad quality
Consistency of binding agent, lubricant and filler

Non-homogeneity of friction material (uneven distribution of abrading medium)

Sudden quenching of hot brake disc
Flaking of particles from the friction ring

Occurs frequently with relatively new brake discs which are still insufficiently run in
Effect:
Brake fade: Brake pedal becomes „hard”

Excessive wear of brake disc and pad

Noise generation (humming, droning, grating)
Position of caliper / pad surface
Symptom:
The brake friction faces are showing signs of uneven pad contact, not reaching across the entire width of the friction ring
Some corroded areas on the brake friction faces

Pads not making contact in this area
Cause:
Inferior pad quality
Evenness / plane parallelism not guaranteed

Functional axes of brake disc and caliper are out of alignment

Caliper is mounted off straight in relation to the brake disc / wheel hub

Partial loss of friction material
Effect:
Brake fade
Brake pedal becomes "hard"

Reduction of friction surface actually available

Partial excessive wear of brake disc and pad

Thermal and / or mechanical overload

Steering wheel wobble / shimmy
Uneven wear of braking surface
Symptom:
Whisteling and squeaking not only while braking
Cause:
Components of the brake caliper inter alia, piston, sealing elements, pins are not checked for wear and / or damage as recommended in the manual

Piston and guide pins are sluggisch or operate uneven; piston cannot be resetted completely
Effect:
Less braking effect

Uneven and increased wear

Uneven thermal overload of the brake disc because of bad sliding of pins

Uneven pressure on the braking surface may lead to a demolished hub because of axial force