440519 Removing and installing wheel with central bolt
WM 440519 Removing and installing wheel with central bolt
Tools
Information on central bolts
Information on tools - central bolt system
Only use socket wrench 9796 -1- on the 911 with centre-lock wheel.
Never use socket wrench 9451 -2- , from the Carrera GT.
Reason: The lockable wheel bolt (locking mechanism) will break off because there is no plunger for releasing the lockable wheel bolt.
This means that the wheel will not be secured. This can no longer be detected once the hub cap is fitted!
Only socket wrench 9796 -1- can be used on the 911 with centre-lock wheel!
To avoid any confusion, affix an appropriate sticker to the special tool from the Carrera GT - socket wrench 9451!
Order number for this sticker = 000.721.945.11
Socket wrench for central bolt system
Component overview - central bolt system
Component overview of central bolt system
Wheels with central bolts will be available for the 911 Turbo in the current model year 2009 (from March 2009/as an option, I-no. 422).
The central bolt system comes as standard on the 911 GT3, as of 2010 model. Technically, the central bolt system is the same as that used on the 911 Turbo. But the wheels are different and the colour of the wheel bolts may be different.
Wheels with central bolts -3- are secured with a wheel bolt -2- (wheel bolt with removable cone ring) to the wheel hub -5-. The wheel bolt -2- is made of high-strength aluminium and has a trapezoidal thread (right-hand thread). The same wheel bolt -2- is used for all four wheels.
The lockable wheel bolt -4- is an assembled component (only available complete), which has toothing that engages in the wheel hub -5- on one side and in the wheel bolt -2- on the other side (if activated).
The lockable wheel bolt -4- can be pulled out when the wheel bolt -2- is removed in order to remove it from the wheel hub -5-. For safety reasons , only remove the lockable wheel bolt -4- in order to check it and then re-insert it immediately in the wheel hub -5-.
Check that the lockable wheel bolt -4- is working perfectly before fitting the wheel.
The contact surfaces of the wheel on the brake disc -6- must be clean and free of paint and grease.
The wheel drivers -7- (5 ea.) comprise the driver pin, sleeve and self-locking screw. Only one set (5 ea./for one wheel) is available as a spare part.
Five new wheel drivers -7- (1 set) must be fitted when replacing the brake disc. Tightening torque for the self-locking screws = 6 Nm (4.5 ftlb.).
Removing and installing wheel
Removing wheel with central bolt
- Only use the permitted special tool -1- socket wrench 9796 on the 911 with centre-lock wheel!
Socket wrench for central bolt
- Important: "Never" use special tool -2- (socket wrench 9451) from the Carrera GT on the 911 with centre-lock wheel.
- To avoid confusion, stick an appropriate sticker on socket wrench 9451 (for the Carrera GT)! Order number 000.721.945.11.
- Reason: The lockable wheel bolt/locking mechanism will break off because there is no plunger (on the Carrera GT tool) for releasing the lockable wheel bolt.
- This means that the wheel will not be secured. This can no longer be detected once the hub cap is fitted!
1. Raise the vehicle only at the jacking points provided. => 4X00IN01 Lifting the vehicle. Alternatively, raise the vehicle (handbrake on) until the wheel you want to work on is up off the ground.
2. Carefully lever the crested hub cap out using a small screwdriver.
To do this, guide the screwdriver deeply into the opening groove and then carefully lift up the cap.
Do not turn the screwdriver to the left or right while doing this!
Stick adhesive tape on the screwdriver if necessary to ensure that the screwdriver does not scratch the surface of the central bolt.
Removing crested hub cap
Information
- The lockable wheel bolt is only released when special tool 9796 is fitted as far as it will go onto the wheel bolt (safety lock on the central bolt is pushed back).
- The socket locks at this position.
- Get a second person to press the brake pedal to prevent the wheel from turning.
- When loosening the central bolt, make sure that the tool remains fully engaged and does not slide off even slightly (risk of damage to the lockable wheel bolt/locking mechanism).
- A very high torque is required in order to loosen the central bolt. Always turn in the correct direction (anti-clockwise to open the central bolt).
3. Socket wrench 9796 -1- (socket) must be fitted and pressed on as far as it will go. The socket -1- locks at this position.
The lockable wheel bolt is then released.
Positioning tool
If the lockable wheel bolt (locking mechanism) is difficult to move in axial direction (becomes tilted in the wheel bolt toothing/socket cannot be fitted), loosen the locking mechanism using a suitable mandrel (press towards the wheel hub).
To ensure that the socket -1- can then be pulled off the wheel bolt (using an acceptable amount of force), grease the O-ring on the release plunger.
4. Unscrew the wheel bolt you released using special tool socket wrench 9796. Get a second person to press the brake pedal to prevent the wheel from turning.
Opening central bolt (turning anti-clockwise)
When loosening the central bolt, make sure that the tool remains fully engaged and does not slide off even slightly.
5. Unscrew the central bolt and set it down in such a way that the conical area or trapezoidal thread cannot get dirty.
Unscrewing central bolt
6. In the case of vehicles with PCCB (Porsche Ceramic Composite Brake), screw an assembly aid 9794 (hub extension) -1- into the wheel hub before fitting the wheel.
This prevents damage to the brake disc when taking off the wheel.
Hub extension (assembly aid)
Then remove the wheel carefully.
Installing wheel with central bolt
1. Examine the safety components listed below carefully before fitting the wheel.
1.1. Check the wheel bolt for damage.
Wheel bolt (central bolt)
There must be no scratches or cracks on the conical area, trapezoidal thread and inner toothing on the bolt.
Replace the wheel bolt if it is damaged or if you have any doubts.
1.2. Check the lockable wheel bolt (locking mechanism/one per wheel).
Lockable wheel bolt (locking mechanism)
1.2.1. Check that the toothed locking pin is not stiff. After pressing the pin into its cartridge, it must return to its original position with force and without catching.
1.2.2. The toothing on the locking pin must not be damaged.
1.2.3. Replace the lockable wheel bolt(s) if they are damaged or if you have any doubts.
1.3. Before screwing on the wheel bolt, check that the lockable wheel bolt (locking mechanism) is engaged (the locking mechanism must be in the wheel hub).
For safety reasons, only remove the lockable wheel bolt (locking mechanism) in order to check it and then re-insert it immediately in the wheel hub.
1.4. All contact surfaces of the wheel, wheel hub and brake disc as well as the trapezoidal thread in the wheel hub must be free of abrasion, sand, dust or chips.
Apply some aluminium paste on the trapezoidal thread of the wheel hub if necessary.
1.5. Apply some aluminium paste on the trapezoidal thread of the wheel hub.
1.6. Apply a thin coating of aluminium paste on the cylindrical part of the wheel hub.
1.7. Only fit brake discs with driver pins that have been approved for centre-lock wheels.
2. Fit the wheel carefully. Make sure not to damage the brake disc when fitting the wheel.
Use an assembly aid 9794 (hub extension) -1- on vehicles with PCCB (Porsche Ceramic Composite Brake).
Hub extension (assembly aid)
When fitting the wheel, the vehicle must not be supported by the wheel to be secured.
3. Check the condition and functional state of the lockable wheel bolt and replace if necessary.
3.1. Pull the lockable wheel bolt out of the wheel hub.
3.2. Check the condition of the lockable wheel bolt and replace it if necessary.
Carry out a function test (element can move axially with automatic return to initial position). Check mechanical state and perform visual inspection (O-ring, inner and outer toothing).
The lockable wheel bolt must not be repaired (O-ring can be replaced of course).
Replace the lockable wheel bolt assembly if it is damaged.
4. Partly disassemble the central bolt if necessary before fitting the wheel and grease the sliding surfaces inside -grey areas (4)- again with Optimoly TA (aluminium grease).
Disassembling and re-greasing central bolt
Generally, there is no need to re-grease the inside of the bolt, except in the following situations:
Cone ring on central bolt
- A very high or very low torque is required to loosen the wheel bolt (more than 700 Nm/518 ftlb. or less than 400 Nm/296 ftlb.).
- In the event of a jerking, fluctuating tightening torque.
- If you feel any stiffness or strip-slick effect when turning the cone ring -1- for the wheel bolt by hand (cone ring -1- turns back and forward). Apply a certain amount of pressure when checking (turning the cone ring to the wheel bolt -arrows- ).
- Before driving on race circuits, disassemble the central bolts and grease them again if necessary.
4.1. Remove cone ring -1- from central bolt -3-.
A circlip holds the cone ring -1- in the wheel bolt -3-.
Disassembling and re-greasing central bolt
To remove the cone ring -1- , detach it from the wheel bolt -3- by tapping sharply on a wooden base (threaded side facing down to the wood).
4.2. Grease the grey areas -4- of the cone ring and wheel bolt (also the thread) and the three reserve bores on the cone ring with aluminium grease (Optimoly TA).
The three reserve bores must be filled so that they are 1/3 to 2/3 filled with aluminium grease.
Re-insert the washer -2- without greasing it (the washer will be re-greased automatically on both sides during assembly and when the components are subsequently screwed together).
4.3. Insert the cone ring -1- into the wheel bolt -3- in such a way that the circlip engages in the groove on the wheel bolt.
5. Grease the conical surface -1- of the central bolt with a very light coating of Optimoly TA (aluminium grease) before fitting each wheel. Make sure no dirt sticks to it.
Greasing conical surface of wheel bolt
Information
When fitting all wheels, the vehicle must never be supported by the wheel to be fitted. => Lifting the vehicle
Lifting the vehicle
6. Insert the central bolt into socket wrench 9796 -1- (until it engages). Fit the central bolt vertically on the wheel hub and screw it on without tilting it.
Screwing on central bolt using socket wrench 9796
Information
The tightening torque was increased from 500 Nm (370 ftlb.) to 600 Nm (444 ftlb.) in the course of model year 2011.
The higher tightening torque also applies to older vehicles.
7. Use a suitable torque wrench (together with socket wrench 9796) to tighten the central bolt using the three-step tightening procedure.
Tightening wheel
7.1. Step 1 -1- : Tighten central bolt to 600 Nm (444 ftlb.).
Get a second person to press the brake pedal to prevent the wheel from turning.
7.2. Step 2 -2- : Loosen the central bolt again (slightly) by approx. 60° (1/6 turn).
7.3. Step 3 -3- : Tighten the central bolt to a final tightening torque of 600 Nm (444 ftlb.).
WARNING
Unsecured central bolt
- Risk of damage to components
- Danger of accidents
-> After fitting the wheel, make sure that the locking pin is engaged correctly in the central bolt.
8. Remove socket wrench 9796 and check that the locking pin -1- has already engaged automatically in the central bolt. The end of the locking pin is then flush with the inner toothing of the central bolt => Wheel bolt secured.
If the locking pin is still at the rear position => Wheel bolt not secured and has not yet engaged in the inner toothing of the central bolt, the central bolt is still not secured and must be secured manually to prevent it from becoming loose.
To do this, turn the locking pin to the left and right using a 1/2-inch square extension until it engages in the central bolt.
This applies to both road and race track use.
Wheel bolt not secured
When the central bolt is secured, the end of the locking pin -1- will be flush with the inner toothing of the central bolt.
Wheel bolt secured
9. Fit the crested hub cap -1- into the central bolt so that the positioning finger is in the opening groove ( -arrows- ).
Then press the cap in until it is seated securely. Grease the rubber ring on the cap lightly beforehand if necessary.
Now lower the vehicle.
Fitting crested hub cap
- Tightening the central bolt in an emergency
If you do not have the correct torque wrench required to tighten the central bolt to the prescribed high tightening torque in a breakdown situation, the emergency tightening procedure must be performed.
The central bolt must always be fitted using the original tool (stored in the luggage compartment).
Tighten the central bolt with a long lever using a lot of force. Then loosen the central bolt again slightly (by approx. 1/4 turn).
Use a torque wrench to tighten the central bolt to exactly 100 Nm (74 ftlb.).
Draw a line at the marking ^ 100 Nm on the wheel.
Emergency tightening procedure
Tighten the central bolt further with a long lever until the square (Stop) marking is aligned with the line you made on the wheel.
This tightens the central bolt sufficiently to allow you to drive to the next qualified workshop.
Tighten the central bolt immediately (at the next qualified workshop) to 600 Nm (444 ftlb.) using the three-step tightening procedure.