Side section / Sub frame

Bush rear suspension side member. 
Sold each - 6 of each required per car



Fits:
Porsche 996 GT3 / GT3 RS - 1999 to 2004

Click 'Zoom in' for large parts diagram.
Diagram ref no 17


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99633123

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Cross brace rear suspension. 
Sold each - 2 required per car



Fits:
Porsche 996 C2 / C4 / C4S - 1997 to 2004
Porsche 996 turbo - 2000 to 2005
Porsche 996 GT3 - 1999 to 2005
Porsche 997.1 C2 / C4 /C4S - 2005 to 2008
Porsche 997.1 turbo - 2007 to 2008
Porsche 997 GT3 - 2007 to 2012
Porsche 997.1 - 2005 to 2008

Click 'Zoom in' for large parts diagram.
Diagram ref no 10



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99733108103

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Cross brace rear suspension.  Sold each - 2 required per car
Mounted across the rear axle, it reinforces the suspension subframe and strut mounting points, reducing flex under load and improving overall stability. By keeping the suspension geometry tight, this brace helps maintain precise handling and extends the life of surrounding components.

Fits:
Porsche 996 C2 / C4 / C4S - 1997 to 2004
Porsche 996 turbo - 2000 to 2005
Porsche 996 GT3 - 1999 to 2005
Porsche 997.1 C2 / C4 /C4S - 2005 to 2008
Porsche 997.1 turbo - 2007 to 2008
Porsche 997 GT3 - 2007 to 2012
Porsche 997.1 - 2005 to 2008

Diagram ref no 10

What It Does: 

• The bracket reinforces the rear suspension geometry. It braces your Porsche's structure to reduce flex under load, improve stability, and maintain alignment under cornering or when encountering bumps. 
• Helps distribute loads through the rear suspension so that components like arms, bushings, struts, and mounts don’t shift or wear prematurely.

Why Replacement Matters: 

• If this bracket is damaged, bent, or weakened, you may experience rear-end instability, excessive movement in suspension under load, or handling that feels loose or unpredictable.
• Worn or misaligned brackets allow structural flex, which can accelerate wear in suspension arms and bushings.
• Proper reinforcement helps maintain ride and safety when driving hard or when the vehicle is aged.

You may need to replace the support brace if you hear clunking or knocking from the rear suspension, notice uneven tire wear, or feel looseness in the car’s handling. A visual inspection showing cracks, bends, or corrosion is another clear sign. It’s also smart to check this part after any rear impact, even a minor one, as damage can affect stability and alignment.

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99733108103

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This genuine Porsche rear axle rubber isolator bush is used within the side-section, bracket and carrier assemblies of selected 996 and 997 911 models. 

Fits

• Porsche 996 Carrera 2 / Carrera 4 3.4L 1997–08/01
• Porsche 996 Carrera 2 / Carrera 4 / Carrera 4S 3.6L 09/01–2005
• Porsche 996 Turbo 2000–05
• Porsche 996 GT2 2001–05
• Porsche 996 GT3 MKI 1999–02 / GT3 MKII 2003>> / GT3 RS 2003–04
• Porsche 997.1 Carrera 2 / Carrera 4 3.6L 2005–08
• Porsche 997.1 Carrera 2S / Carrera 4S 3.8L 2005–08
• Porsche 997.1 Turbo / GT2 / GT3 / GT3 RS 2007–09
• Porsche 997.2 Carrera 2 / Carrera 4 3.6L 2009–12
• Porsche 997.2 Carrera 2S / Carrera 4S 3.8L 2009–12
• Porsche 997.2 GT3 / GT3 RS 2010–11
• Porsche 997.2 Turbo 2010–13 / GT2 RS 2011–13

Diagram: Ref no 11

What This Product Does

The isolator forms a compliant interface at its designated rear axle mounting location. Its rubber construction cushions adjoining assembly parts, accommodates minor movement and reduces the direct transfer of vibration through the side-section or carrier connection.

Functions

• Separates associated components at the specified mounting point
• Cushions minor movement within the rear axle assembly
• Limits vibration passing through the mounting interface
• Supports the intended location of the side-section or carrier components
  
  

Technical Details

• Manufacturer: Porsche
• Part number: 99633138500
• Porsche catalogue description: rubber mounting
• Alternative diagram description: rubber bush or rubber isolator
• Installation area: rear axle side section, side part, bracket or carrier
• Diagram quantity: six per applicable assembly
  
  

Symptoms of Fault

• Rubber showing splits, compression, hardening or distortion
• Knocking or movement around the rear axle mounting area
• More vibration entering the body structure
• Looseness between associated carrier or side-section components
• Rear suspension behaviour that changes as the mounting moves under load
  
  

Why Replacement Matters

Deteriorated rubber may cease to isolate the connection or hold adjoining parts in their intended relationship. Renewing the mounting helps reinstate the compliant interface specified for the assembly. The surrounding bolts, locknuts, cross members, transverse struts and side sections should also be inspected, since looseness or wear in these parts can produce similar symptoms. An appropriate geometry check may be required after substantial rear axle or suspension work.

FAQs

• Is this an original Porsche component?
  Yes. Porsche lists 99633138500 as a rubber mounting in its parts catalogue.
• Where does the isolator fit?
  It appears in rear axle side-section, side-part, bracket and carrier diagrams for applicable 996 and 997 models.
• How many are shown in the assembly?
  The supplied exploded-diagram data specifies a quantity of six for each applicable assembly. Confirm how many are needed for the particular repair.
• Should other components be checked?
  Yes. Inspect the adjacent hardware, cross members, struts and mounting areas for corrosion, damage, movement or wear before installation.

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99633138500

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Rear suspension support brace for vehicles with a manual transmission. This is the singular brace which runs perpendicular to the car's body - not to be confused with the two braces (x2 99733108103, ref. no. 10 in the parts diagram) which sit at an angle and form a triangular shape alongside this part.



Fits:
Porsche 996 Carrera 2 / 4 / 4S 1998-05*
Porsche 996 Turbo 2001-05*
Porsche 996 GT3 1999-05*

Porsche 997.1 Carrera 2 / 2S / 4 / 4S 2005-08*
Porsche 997.1 Turbo / GT2 2007-09*
Porsche 997.1 GT3 2007-11*

*Please be advised, this part is only correct for vehicles with a manual transmission. If your model is Tiptronic, you will need to order 99733117100 instead.

Side panel, rear axle.



Fits:
Porsche 996 GT2 2001-05
Porsche 996 GT3 1999-05  *also for Cup cars

Click 'Zoom in' for large parts diagram.
Diagram ref no 1

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99633105

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Silent block set for rear axle sub frame. Porsche 996, 997 
(Set of 3 bushings for one side) for Left and Right, 2 Sets required
Standard street version.

Fits:
Porsche 997

Porsche 996

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99633105XXX

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Solid subframe bushing set. 12 bushings in kit. 1 kit req'd per car.



Fits:
Porsche 996 / 997

Improved Handling and Precision
Our Rear Subframe Solid Bushing kit improves handling and precision by providing geometry correction for lowered cars and eliminating deflection. Porsche recognizes these performance benefits and uses a similar solid rear subframe mounting approach on the latest GT3 street and Cup racecars.

Replaces stock rubber bushings in the rear subframe of the Porsche 996 and 997 cars, raising the subframe into the chassis 6.5mm (.25 inch).

Geometry Correction
Lowering the 996/997 provides the benefits of lower center of gravity and improved appearance. Unfortunately lowering also causes the rear suspension members to angle down as the inner links drop with the chassis and the outer links remain at wheel upright height. This downward angle harms performance.

With the suspension members angling up towards the wheel the Roll Center is lowered which causes increased chassis lean, toe and camber curves are shifted and become less optimal, static toe and camber adjustments are shifted often exceeding the range of the stock adjusters.

Our kit raises the rear subframe .25 inches (6.5mm) to help reverse the negative effects of lowering. Suspension member angles are improved and performance is enhanced. Our upper bushing fits inside the subframe, eliminating the entire thickness of the upper rubber bushing for the greatest possible geometry correction achievable from bushings alone.

Eliminate Deflection
Stock rubber bushings compress and deform under heavy cornering, braking, and acceleration loads. The compliant rubber bushings allow the entire rear subframe shift about relative to the chassis. Rear camber and toe settings wander along with the subframe making the car less predictable, less stable in turns.

Our solid bushings replace the compliant rubber and do not deform under cornering loads, keeping the subframe in position and alignment true even under heavy cornering loads. The car becomes more predictable and easier to drive fast.

Build Quality
Each bushing consists of two pieces, an upper plug and lower puck. The plug is machined from solid aluminum with knurled edges for perfect fit.

Lower puck is machined from solid steel with zinc finish for protection.

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