Assembly procedure for Alcon bobbin drive discs

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Two types of bobbin are available:

  • Bobbin drive system with bolt (X401, series)
  • Bobbin drive system with integral stud (X405 series)


Assembly procedure

  1. Place the bobbins in the slots in bell, with the ‘ears’ of the bobbin at right angles to the outside diameter of the bell, unless otherwise specified.
  2. Push the bolt through the bobbin so that it engages in the disc.
  3. Apply a small amount of thread retainer, enough to cover 2-4 threads, to the portion of bolt protruding from the disc. Fit a nut onto each bolt and finger tighten.
  4. Tighten the nuts in a star sequence, rather than a rotational sequence, to the specified torque using the appropriate tools.  Prevent the bolt from rotating when applying the specified tightening torque to the nut.  Do not hold the nut and tighten the bolt as it will cause the bobbin to rotate and the bell will lock up.
Where bobbins with integral studs are supplied (405 series bobbin) Alcon tool TSB3430X577 is available and is used to prevent the bobbin from rotating during tightening.   This tool can also be used to ‘square’ both 401 & 405 series bobbins after tightening to ensure the bell is not locked up. Once assembled, the bell should be a ‘rattle’ fit on the disc and bobbins.
Once assembly is complete, use feeler gauges to check that the float between the bobbin and bell is correct and uniform on all bobbins.
General notes
  1. Ensure that all parts are clean and grease free
  2. Approved thread retainer: - Loctite 243 (Blue)
  3. Tightening torque: 0.25” UNF 16-18Nm (11.8 – 13.3 lb ft)

Installing Alcon Extreme Advantage Brakes

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Alcon Advantage Extreme brake kit installation instructions

Important: read these instructions carefully before fitment.

Alcon Advantage Extreme brake kits are designed to replace the original brake calipers and discs. However, vehicle production tolerances may exceed those that the kit will accommodate, and the points below must be carefully observed during installation to ensure that the correct clearances are maintained. This brake kit must be fitted by a suitably qualified mechanic.

  1. Remove the original caliper and disc
  2. Raise the vehicle on a suitable lift or stands and remove the wheels.
  3. Clamp the flexible brake hose to reduce brake fluid loss and disconnect the hose from the caliper. Disconnect any pad wear indicator wires and remove the caliper.
  4. Remove the brake disc. Fit the new caliper and disc
  5. Ensure that the hub flange is completely flat and clean.  Note that any ‘bruising’ or out of flatness will cause brake vibration.
  6. If necessary, prepare the hub face to remove any high spots prior to fitting the brake disc.
  7. Fit the disc assembly to the hub. The discs are handed and must be fitted to the correct side of the vehicle, with direction of rotation as shown right. With the disc assembled to the hub, check that there is a minimum of 5mm clearance between the disc inner face and the lower suspension/steering joint.
  8. Unless special longer bolts are provided in the kit, use the original bolts and washers to loosely bolt the mounting bracket to the upright. Locate the caliper over the disc and fit the caliper retaining bolts. Do not tighten at this stage. The caliper must be orientated so that the disc rotates past the small piston first, and with bleed screws uppermost.
  9. To prevent overheating, radial clearance between the disc and caliper must not be less than 2.5mm in all directions. When the pads are fitted, the top edge of the pads should be approximately 0.8mm below the disc outside diameter and the disc must be central in the caliper within +/- 0.5mm. Use the 0.5mm shims provided to lift the caliper on the bracket or to adjust the bracket position until the caliper is correctly positioned. Fit an equal quantity of shims to each end of the bracket as required.
  10. Fit the road wheel to check there is a minimum of 2.5mm clearance between the wheel and caliper in all directions.
  11. Do not make any modifications to the caliper. Alcon accepts no liability whatsoever for the consequences of using a caliper that has been modified without its express written approval.
  12. When the caliper/bracket assembly has been positioned correctly and clearances have been checked, remove and clean the bracket to upright mounting bolts. Apply thread locking compound to the threads, fit the bracket to the upright and tighten the bolts to the vehicle manufacturers’ specified torque.
  13. Remove the caliper retaining bolts and apply thread locking compound to the threads. Fit each bolts with the washer provided and tighten to 108Nm
  14. Check that new pads move freely in the caliper. With the pistons pushed back into the bores, there should be a minimum clearance of:
    1. 0.25mm between the piston end and pad backplate
    2. 0.4mm between end of the pad and the caliper
  15. Remove the original hose and replace with the braided hose supplied. Connect the hose to the caliper and, ensuring it is not twisted, connect it to the vehicle, including the original fastening clip. Check that the brake line length allows for all combinations of steering lock and suspension movement and that the hose does not come into contact with any suspension component, the wheel or the tyre in any position.
  16. Tie-back the pad wear indicator wires.
Please see our LEARN section for brake bleeding and bedding procedures.
Note:  Every effort has been made to ensure that the information provided is correct.  However reserves the right to change information without notice.


How to bed in your brake pads

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Disc and pad bedding and running in

1. Pre-bedding at Alcon Most discs and pads supplied by Alcon are pre-bedded. The purpose of pre-bedding the disc is to deposit an even transfer layer of friction material on to the surface of the disc. The secondary reason for pre-bedding the disc is to thermally condition the disc. The objective of pre-bedding the pad is to take the pad through a heat cycle during which the resins contained within the pad are cured, additionally, any high spots on the surface of the pad are removed. After the discs have been pre-bedded and allowed to cool, the disc and pads can be bolted on to the car and should be ready for competition use providing that the discs and pads are “run-in” correctly.

2. Use of pre-bedded discs in competition Care needs to be taken during “running-in” to obtain the best performance and life from pre-bedded discs and pads. The running-in of discs and pads on the car immediately prior to competition use ensures that the face of the disc and pad are mated, removing any high spots. Lightweight discs are particularly sensitive to potential problems during use, failure to correctly run-in the discs and pads can result in problems including:


  • Long pedal
  • Poor feel and modulation
  • Vibration
  • Premature wear
  • Disc cracking


All discs can suffer from premature cracking, this is normally caused by thermal shock, occurring when the disc is either cooled or heated too quickly. Additionally, an excessive rate of disc temperature increase can result in failure of the heat to be absorbed into both braking faces and the vanes evenly. Any significant temperature variation between the opposing flanges, including the mounting flange, can cause and promote disc coning and stresses within the disc cheeks, normally leading the problems listed above. Heavier-weight discs are more stable and less prone to these problems, due to the increased structural rigidity gained from 48 vane design and generally increased flange thickness. It is still advisable to run-in the discs carefully as per instructions to follow.

To prevent these problems, an appropriate and proven “running-in” procedure needs to be followed, during rallies and tests. We suggest that the following procedures are employed:

3. “Running – in” instructions

48 vane discs


  • Make 5 – 10 light stops from slow speed and light pedal pressure to complete system check.
  • Undertake 15 decelerations from 80 to 40 kph, light to moderate pedal pressure. (2.5 - 3.0 seconds, line pressure 20 bar)
  • Undertake 15 decelerations from 120 to 60kph, light to moderate pedal pressure. (4.0 seconds, line pressure 20 bar)


24 vane discs


  • Blank cooling duct completely (if possible)
  • Make 5 – 10 light stops from slow speed and light pedal pressure to complete system check.
  • Undertake 15 decelerations from 60 to 40 kph, light pedal pressure. (2.0 seconds, line pressure 25-30 bar)
  • Undertake 15 decelerations from 80 to 40 kph, light to medium pedal pressure, (2.5-3.0 seconds, line pressure 20 bar), surface temperature should be around 3500 C.
  • Remove ducting blank (again, if possible)



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