Alcon Road Kit Bobbin Assembly Instructions

Assembly Procedure - This is for Alcon Extreme brake kits with the semi-gloating style Bobbins.

1. Insert bushing into the aluminum hat and press in.

2. Insert wavo springs into location diameter on every other bushing so that there are an even spread of springs. Ensure correct orientation of spring (see fig.1).

3. Insert bobbin into bushing and push the bobbin through so that it engages with the disc.

4. Push bolt through bobbin.

5. Apply a small amount of thread retainer, (Loctite 243 Blue) enough to cover 2-4 threads, to portion of bolt protruding from the disc. Hand assemble a nut onto each bolt so that they are finger tight.

6. Tighten the nuts (not the bolt) in a start sequence.   Tightening Torques: M6 10-11 nM or  7.4-8.1 ftl-lbs

7. Apply a small amount of red paint to the end of each bolt to indicate that the nuts have been torqued correctly.

8. Ensure that all the springs are located under the bobbin flange and located securely in the recess of the bushing and not trapped between the bobbin flange and the bell.

STaSIS Assembly Instructions for Rotor Hats

All information contained in this article are the property of STaSIS engineering and are provided as a courtesy to AlconKits customers.  If you do not feel comfortable with these instructions we would encourage you to contact one of our service partners.  You can bring in your vehicle or send in the rotors and hardware for service.  See our lists of service providers nearest you here:  AlconKits Installers and Service Providers.


Tools Required:

  • Vice
  • In-lb Torque Wrench
  • 5/16” socket
  • 7/16” open end wrench or socket

Torque Specs for NAS Nuts: 120 in-lbs


Special Notes: Note orientation of mounting hardware in figure 1. Install Bellville washers on every other bolt, and note washer orientation as seen in figure 2.



Refer to the to the diagrams below. Note the orientation of the Belleville washers.  They are located on the Bobbin.  The Belleville washers are designed to provide spring force against the rotor to prevent rattling of the rotor and float capability.




Note the parts used for your rotor installation.

1. Insert bolts (1) into Bobbins (2)

2. Install Belleville washers (3) onto bobbins (2) as shown in figure 1.

3. Insert Bolts/Bobbin/Washer assembly into the rotor as shown in figure 2.

4. Install hardened washers (4) onto bolts on the outside of the rotor

5. Place hat over bolts.  The hardened washers may create a gap.

6. Install jet nuts onto bolts over hats and tighten loosely by hand.

7. Torque jet nuts in a star pattern to final torque.  (120-in-lbs).

Assembly procedure for Alcon bobbin drive discs

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)