do not press the back button…
Enter your VAT number here and click Verify:
Your details have been verified. VAT number registered to:
,
.
Your order will now be zero rated for VAT purposes. We reserve the right to verify these details after your order request has been made and reinstate VAT if required.
Your VAT details were not recognised or were invalid. Your VAT number must be matched to your Billing Country as specified above. This is currently specified as . You do not need to enter the country code part of your VAT number as this has already been selected in your billing address details above.
The VAT number checking service is currently offline. Please supply your VAT details within the comments or special instructions field below and we will apply a VAT discount after placing your order request.
- Porsche 928S4 5.0L 1987-92
- Porsche 928GT 5.0L 1989-91
- Porsche 928GTS 5.4L 1992-95
OE Match engine crankcase breather hose for Porsche 928 S4, GT, and GTS models from 1987 to 1995. This replacement hose runs from the plenum to the MAFS connector, helping maintain correct crankcase ventilation, intake sealing, and smooth engine operation.
Fits:
Porsche 928 S4 / GT 1987 - 1991
* Engine code: 2841 / 2842 / 2847
Porsche 928 GTS 1992 - 1995
* Engine code: 2849 / 2850
Diagram ref no 11
The crankcase breather hose routes crankcase vapours from the engine ventilation system into the intake system for controlled recirculation. A correctly sealed hose helps prevent vacuum leaks, unmetered air entry, oil vapour escape, and poor running caused by damaged or split breather hoses.
Functions
• Replaces the engine crankcase breather hose
• Fits from the plenum to the MAFS connector
• Supports correct crankcase ventilation routing
• Helps maintain intake system sealing
• Helps prevent vacuum leaks and unmetered air entry
• Supports smooth idle, throttle response, and reliable engine running
• Suitable for intake service, breather system repair, or engine bay restoration
• OE Match replacement for Porsche 928 S4, GT, and GTS breather system maintenance.
Why Replace This Part?
Crankcase breather hoses can harden, crack, split, collapse, or become oil-soaked due to age, heat, oil vapour exposure, and engine bay conditions. A damaged hose may cause rough idle, hesitation, vacuum leaks, intake air leaks, oil vapour smell, oil mist residue, or incorrect air metering. Replacing the hose helps restore correct breather system function and intake performance.
When to Replace This Part
• Breather hose is cracked, brittle, split, collapsed, or leaking
• Rough idle, hesitation, or poor running is present
• Vacuum leak or unmetered air symptoms are detected
• Oil vapour smell or oily residue is visible around the hose
• Plenum, MAFS connector, or intake system service is being carried out
• Engine crankcase breather system maintenance is in progress
• Vehicle is undergoing Porsche 928 engine bay restoration or refresh.
Where it fits on the car
This hose fits within the engine intake and crankcase breather system, running from the plenum to the MAFS connector on Porsche 928 S4, GT, and GTS models.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
92811017409
The product you are viewing cross references to these numbers
- Porsche 991.1 Carrera C2 3.4L (350 Bhp) 2012-16
- Porsche 991.1 Carrera C2S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Carrera C4 3.4L (350 Bhp) 2012-16
- Porsche 991.1 Carrera C4S / GTS 3.8L (400/430 Bhp) 2012-16
- Porsche 991.1 Turbo 3.8L (520 Bhp) 2014-16
- Porsche 991.1 Turbo S 3.8L (560 Bhp) 2014-16
- Porsche 991.2 Turbo Coupe 3.8L (540 Bhp) 2016-19
- Porsche 991.2 Turbo S Coupe 3.8L (580 Bhp) 2016-19
- Porsche 991.2 Turbo Cabriolet 3.8L (540 Bhp) 2016-19
- Porsche 991.2 Turbo S Cabriolet 3.8L (580 Bhp) 2016-19
- Porsche 991.2 GT2 RS 3.8L PDK (700 bhp) 2018-19
Vacuum Line.
The Genuine Porsche Vacuum Line 9A111005523 is an original replacement vacuum pipe used within the brake-servo vacuum system of selected Porsche 911 991-generation models.
Fits:
Diagram Ref No 13
The line works with the engine-driven vacuum pump to provide the vacuum required by the brake booster, also known as the brake servo.
Brake assistance allows the driver's pedal input to be multiplied so that strong braking force can be achieved without excessive pedal effort.
Because modern Porsche engines cannot always provide a consistent level of intake-manifold vacuum under every operating condition, a dedicated vacuum pump is used to maintain reliable brake-servo assistance. The vacuum line provides the sealed connection required to transfer this vacuum through the system.
Age, engine-bay heat, vibration and repeated thermal cycling can eventually cause vacuum lines, seals and connections to deteriorate. A leak can reduce available brake assistance and may result in a noticeably harder brake pedal.
Replacing a damaged or leaking vacuum line helps restore the sealed vacuum circuit and maintain reliable power-assisted braking.
What This Product Does:
The vacuum line forms part of the connection between the brake-servo vacuum pump and the vehicle's brake-assistance vacuum circuit.
Its main functions are to:
- Carry vacuum generated by the vacuum pump.
- Maintain a sealed vacuum circuit.
- Support correct brake-servo operation.
- Help maintain normal brake-pedal effort.
- Provide consistent power-assisted braking.
- Accommodate engine movement and vibration.
- Prevent atmospheric air leaking into the vacuum system.
- Maintain reliable operation under different engine loads.
Symptoms Of Wear Or Failure:
Possible symptoms include:
- Brake pedal feeling harder than normal.
- Increased effort required to stop the vehicle.
- Reduced power assistance.
- Brake pedal becoming hard after repeated applications.
- Hissing from the engine or vacuum-line area.
- Visible cracks in the vacuum pipe.
- Split hose sections.
- Loose or damaged connectors.
- Damaged O-ring seals.
- Vacuum line becoming brittle.
- Vacuum line becoming distorted by heat.
- Reduced stored brake assistance after the engine is switched off.
- Changes in brake-pedal feel.
Why Replacement Matters:
Replacing a cracked, leaking or damaged Vacuum Line helps restore:
- Correct brake-servo vacuum.
- Normal brake-pedal assistance.
- Consistent pedal effort.
- Reliable vacuum retention.
- Correct vacuum-pump operation.
- Airtight system integrity.
- Predictable braking response.
A properly sealed vacuum system is essential for maintaining the brake performance characteristics intended by Porsche.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
9A111005523
The product you are viewing cross references to these numbers