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Technical Information

Technical Information

Floating Caliper Brake

Floating caliper brakes have the following advantages over the fixed caliper:

  1. Less fitting space required at the wheel side
  2. This allows a negative kingpin offset
  3. No highly stressed screw connections (expansion screws) required
  4. Weight advantage (e.g., only one brake piston)
  5. Lower temperature generation in the brake fluid due to only one contact surface between piston and brake pad

Floating caliper brakes have the following advantages over the fixed caliper:

  1. Cylinder housing including piston and sealing ring
  2. Guide spring
  3. Frame
  4. Support
  5. Brake pads
  6. Pad retaining pins
  7. Expansion spring
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The support, as with the fixed caliper, is firmly screwed to the wheel suspension. It holds the brake pads in place and guides the frame in 2 grooves (linear support, to keep sliding forces as low as possible).

The circumferential wheel forces resulting from the braking torque are absorbed by the stationary support.
The floating frame therefore only transmits the clamping forces. In contrast to the fixed caliper, the floating caliper has only one hydraulic cylinder. The piston acts directly on the inner pads facing the center of the vehicle.

As soon as the piston presses the pad against the disc because of the hydraulic pressure built up in the main cylinder, and has overcome the clearance S2 the cylinder housing starts shifting against the frame, in the opposite direction to the piston. The frame now pulls the outer pad, located in the support, against the rotating disc, at the same time overcoming the clearance S1 ; in this condition, all pads are in braking position.

Clearance adjustment after completing the braking action and the adjustment to compensate for pad wear are the same as for the fixed caliper. The locating spring provides for a spring-loaded contact between frame and support thereby preventing noise development

As with the fixed caliper, the pads can be changed while the floating caliper brake remains installed in the vehicle.

After the lower pad retaining pin has been carefully driven out, the expansion spring can be removed.

The piston-side brake pad must now be removed first. In order to remove the pad on the frame side, the frame with the cylinder housing must be pushed outwards.
This will cause the frame spigot to be pushed out of the backing plate, and the pad can be pulled out of the support housing. The dust seal (dust collar) and the position of the piston shoulder should then be inspected, as previously described for the fixed caliper.

If repair work is necessary, the instructions given in both the workshop manual and the fitting instructions must be strictly adhered to.

Before the new pads are installed, the caliper piston must be carefully pushed back (check the brake fluid level in the reservoir, if necessary drain fluid off, to prevent an overflow).

After the new pads have been fitted, the brake pedal should be operated several times to optimize the caliper clearance!

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