Repairing front wheel bearing housing thread

Information 

All tasks required during thread repairs must be done manually.

Use cutting oil for thread repairs.

• Do not use a power drill  .
• Do not use an impact bolter  .
• Do not use tools to secure the assembly aid. Tighten fastening screw by hand  .

Information 

The wheel bearing housing shown may differ from the original part.

Overview of tools: Brake calliper repair set VAS 6627 WE 1376 

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Overview of tools: Time-Sert thread repair set Nr.122-1 Pos.5 

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Information 

The wheel bearing housing can remain installed during thread repairs.

• The numbers shown in the illustration have the same end numbers as in the tool sets  .
• For clarity, some of the repair steps are shown on the removed wheel bearing housing  .

1. Fit the assembly aid on the intact thread with a fastening screw -3-  . You will be working on the other side with the defective thread.

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2. Drill out the defective thread.
   1. 2.1. Installation sequence for drilling out the thread.

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      1	Drill bit, Time-Sert thread repair set No. 122-1 Item 5
      7	Guide sleeve, M14, internal diameter: 14.5 mm, Brake calliper repair set VAS 6627
      6	Threading die holder, Brake calliper repair set VAS 6627

   2. 2.2. Fit guide sleeve into assembly aid. Drill out the thread as far as the stop using the threading die holder and drill bit.
   3. 2.3. Remove assembly aid. Carefully blow the chips out of the bore hole. Wear protective goggles.
3. Countersink the bore hole.
   1. 3.1. Using the seat miller, countersink the bore until it is sufficiently deep to allow the stop of the seat miller to sit on the wheel bearing housing (as far as the stop). -2- 

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   2. 3.2. Bore hole countersunk. -A 

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   3. 3.3. Check the countersink depth of the bore hole

      Fit the M14 threaded bush into the bore hole against the screw-in direction. -5- 

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   4. 3.4. The collar of the M14 threaded bush must be sitting in the recess up to the first thread. -5- 

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4. Fit the assembly aid with a fastening screw. -3-  .

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5. Cut thread.
   1. 5.1. Installation sequence for cutting the thread.

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      1	Assembly aid, Brake calliper repair set VAS 6627
      3	Tap, Time-Sert thread repair set No. 122-1 Item 5
      8	Guide sleeve, M14, internal diameter: 12 mm, Brake calliper repair set VAS 6627
      6	Threading die holder, Brake calliper repair set VAS 6627

   2. 5.2. Oil the tap. -3- 

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   3. 5.3. Insert the tap into the assembly aid. The guide sleeve is projecting slightly out of the assembly aid. But it has made contact. The guide sleeve will drop during the cutting process using the threading die holder.

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      1	Assembly aid, Brake calliper repair set VAS 6627
      3	Tap, Time-Sert thread repair set No. 122-1 Item 5
      8	Guide sleeve, M14, internal diameter: 12 mm, Brake calliper repair set VAS 6627

   4. 5.4. Carefully cut the thread as far as the end of the bore hole (as far as the stop) using the tap.

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   1	Assembly aid, Brake calliper repair set VAS 6627
   8	Guide sleeve, M14, internal diameter: 12 mm, Brake calliper repair set VAS 6627
   6	Threading die holder, Brake calliper repair set VAS 6627

6. Re-mill the bore hole.

   Information 

   Mill in/countersink the bore hole.

   • The collar of the threaded bush must be sitting at least → Length: 0.2 mm in the bore hole under the collar of the wheel bearing housing  .
   • The collar of the threaded bush must not be projecting out  .
   1. 6.1. Using the seat miller, countersink the bore again until it is sufficiently deep to allow the stop of the seat miller to sit on the wheel bearing housing (as far as the stop). -2- 

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   2. 6.2. Carefully cut the thread again as far as the end of the bore hole (as far as the stop) using the tap. This removes the remaining milling burrs. The tap must screw out without catching!
   3. 6.3. Check again to make sure that the collar of the threaded bush has disappeared in the recess. If it has not disappeared, repeat the milling process! -5- 

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7. Clean the thread  (using brake cleaner for example) and carefully blow the chips out of the bore hole. Wear protective goggles.
8. Insert the M14 threaded bush.
   1. 8.1. Screw in the M14 threaded bush as far as possible by hand.
   2. 8.2. Only oil the screw-in tool! Screw in the screw-in tool as far as possible by hand. Continue screwing until the threaded bush is sitting slightly deeper in the bore hole on the wheel bearing housing.

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   3. 8.3. Then, screw the threaded bush in further using the threading die holder and the screw-in tool. -4- 

      Information 

      Mill in/countersink the bore hole.

      • The collar of the threaded bush must be sitting at least → Length: 0.2 mm in the bore hole under the collar of the wheel bearing housing  .
      • The collar of the threaded bush must not be projecting out  .
   4. 8.4. Once the M14 threaded bush is screwed in so that it is sitting slightly deeper in the bore hole on the wheel bearing housing, you will feel the increased resistance. Continue screwing carefully until there is less resistance again.
   5. 8.5. The screw-in tool must screw out without catching! -4- 
9. Check that the M14 threaded bush is seated correctly.
   WARNING: Threaded bush sticking out of wheel bearing housing.

   • Brake calliper can become loose.

   → The contact surface of the brake calliper must be flush with the contact surface of the wheel bearing housing.

   → The brake calliper must not be supported on the threaded bush.

   → There must be NO gap between the brake calliper and wheel bearing housing.

   1. 9.1. The M14 threaded bush -5-  is inserted at the correct position if the collar of the M14 threaded bush is below the contact surface of the brake calliper -A-  ! The M14 threaded bush must not be projecting out.

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   2. 9.2. The M14 threaded bush is at the correct position if it is sitting slightly deeper in the bore hole.
10. Clean the thread with brake cleaner after you have completed the repair work. The thread must be free of grease and chips  .