Bonnet Gas Struts

If your vehicle’s front bonnet has become heavy to lift, slowly creeps down, or completely fails to stay open in cold weather, it is time to replace your factory gas springs. Over years of operation, internal nitrogen gas naturally permeates through rubber seals, dropping the internal lifting force (F1) below safe operational thresholds. As a leading IATF 16949 certified manufacturer, GASTAC designs and supplies precision-engineered bonnet gas struts that deliver effortless lifting assist, smooth end-dampening, and maximum structural safety for both direct OEM replacement and manual-to-hydraulic retrofitting.

What Are Bonnet Gas Struts?

Common Symptoms of Failed Bonnet Gas Struts

Over years of operation, internal nitrogen gas naturally leaks past the rubber seals of your vehicle’s lift supports. In Commonwealth markets like the UK and Australia where heavy steel or aluminum front panels are called bonnets, a weak strut quickly escalates from an inconvenience to a dangerous safety hazard. Watch for these five definitive failure signs before working under your engine bay:

• Immediate Drop: The bonnet fails to counteract dead weight and slams shut the moment you let go.
• Slow Creeping: The struts hold the panel open initially, but slowly sag and drop within a few minutes.
• Winter Failure: The bonnet stays open in summer but drops completely in cold weather due to thermal pressure loss.
• Abnormal Weight: You feel zero pneumatic assistance when lifting, forcing you to muscle the raw weight manually.
• Visible Oil Leaks: Greasy oil residue coats the shiny metal piston rod, confirming a ruptured multi-lip seal.

Safety Reminder: Always replace bonnet gas struts in pairs. Changing only one side causes asymmetric mechanical stress, which can warp your vehicle’s delicate active hinges or cause uneven lifting speed.
 

Bonnet Gas Struts OEM Specifications

OEM-grade bonnet gas struts must strictly match original factory blueprints. Any deviation in length or pressure will cause the bonnet to misalign, stress the active hinges, or fail to support the panel’s dead weight. To guarantee a seamless drop-in fit, replacement struts must comply with the following mandatory dimensional, physical, and material criteria:

OEM	Photo	Rod / Tube Ø	Stroke	Extended Length	Force	Year
51237040711		8 / 18 mm	365 mm	830 mm	120N	ROLLS-ROYCE PHANTOM 2003-2017
4L0823359		8 / 18 mm	190 mm	485 mm	170N	AUDI Q7 2006 – 2015
3w0823475B		8 / 18 mm	215 mm	535 mm	160N	BENTLEY CONTINENTAL 2005 – 2013
99651155101		8 / 18 mm	60 mm	225 mm	560N	PORSCHE 911 1997 – 2005
4G8823359A		8 / 18 mm	120 mm	320 mm	380N	AUDI A6 2010 – 2018

Need custom lengths, specific end fittings, or specialized Newton forces? Visit the official [GASTAC Online Store] to submit your blueprints. Our engineering team provides rapid prototyping and volume pricing for commercial applications.
 

Interior Technology

• Highest corrosion resistance achieved through powder coated cyclinders and special treated piston rod surfaces.
• Minimal friction for the production of lowest extension forces.
• Great life cycles.
• Protection against vibration and light side forces.
• Integrated grease chamber.
• Low break away forces.
• Installation and storage in any position.

GASTAC Premium Automotive-Grade Manufacturing Process

GASTAC miata hood struts are manufactured using durable automotive-grade materials designed for long-term reliability.

• High-Pressure Nitrogen Gas System: Each gas strut uses stable nitrogen pressure to ensure smooth lifting performance and controlled hood movement.
• Precision Sealing Technology: Advanced sealing systems help minimize pressure loss and extend operational lifespan.
• Corrosion-Resistant Components: The piston rod features anti-corrosion treatment for improved durability under varying environmental conditions.
• Stable Damping Performance: Proper damping helps prevent sudden hood movement and improves user experience.

Simple Bolt-On Install Miata Hood Struts

Installing Miata hood struts is designed to be quick, clean, and fully DIY-friendly. No cutting, no welding, and no complex modifications required.

1. Step 1 — Secure the Hood: Open the hood fully and make sure it is safely supported.
2. Step 2 — Remove the Hood Prop: Take off the original miata hood prop from its mounting position.
3. Step 3 — Install the Struts: Attach brackets and connect the gas struts to factory mounting points.
4. Step 4 — Test the Operation: Gently open and close the hood to ensure smooth lifting and stable support.