A Guide to the 2008-2013 BMW 135i Front Suspension Strut Mount
Restore your BMW's sharp handling and eliminate suspension noise by choosing the right strut mount.
- Always replace strut mounts in pairs when replacing struts to save on labor and ensure balanced handling.
- A four-wheel alignment is mandatory after replacement to prevent poor handling and rapid tire wear.
- Inspect the strut towers for 'mushrooming' (upward deformity), a known weak point on the 135i chassis.
- For durability, choose OEM-supplier brands like Sachs or premium aftermarket like Bilstein; economy brands may have a shorter lifespan.
Is Your 135i Making Noise Over Bumps?
A common sign of a failing strut mount is noise. You might hear a distinct 'clunking,' 'popping,' or 'creaking' sound from the front of the car, especially when driving over bumps, potholes, or turning the steering wheel at low speeds. Other symptoms include excessive vibration through the steering wheel, a feeling of looseness or instability in the steering, and uneven wear on your front tires. In some cases, a visual inspection under the hood may reveal cracked or degraded rubber on the mount, or even a visible deformity in the strut tower sheet metal, known as 'mushrooming,' if the car has hit a significant pothole.
A Vehicle-Specific Weak Point: Mushrooming Strut Towers
The E82 chassis, which the 2008-2013 135i is built on, is known for having front strut towers that can deform or 'mushroom' upwards from a hard impact, like hitting a pothole. This happens when the force of the impact travels up the strut and pushes the mount into the relatively thin sheet metal of the tower. This can ruin wheel alignment and is a costly repair. While replacing the mount, inspect this area carefully. Some owners install aftermarket strut tower reinforcement plates to help distribute the load and prevent this from happening.
Choosing the Right Aftermarket Strut Mount
When shopping for a new strut mount, you'll find several brands. They generally fall into three quality tiers. Since the labor to replace this part is significant, choosing a quality component is recommended to avoid doing the job twice.
Tier 1: OEM & Premium Aftermarket
These brands are either Original Equipment Manufacturers (OEM) for BMW or are known for high-quality engineering that meets or exceeds OEM standards. They are the safest bet for longevity and performance.
- Sachs: Often an OEM supplier for BMW, Sachs parts are a direct equivalent to the Genuine BMW part in terms of fit, ride quality, and durability.
- Bilstein: A highly respected German brand known for suspension components. Their B4 line is an OE-replacement quality part, while their B6 line offers a performance upgrade.
- CRP (Rein): Generally considered a high-quality aftermarket brand that manufactures parts to strict engineering standards, often matching the original rubber hardness and corrosion resistance.
Tier 2: Standard Aftermarket
These brands offer a good balance of quality and price. They are a solid choice for a daily driven vehicle under normal conditions.
- KYB: A major global manufacturer of shocks and struts, KYB mounts are known for providing good, reliable OE-quality performance.
- Monroe: A well-known aftermarket brand offering a wide range of suspension parts that provide a functional, budget-friendly replacement.
- Vaico: A German brand offering a vast catalog of aftermarket parts that serve as a cost-effective alternative to OEM components.
Tier 3: Economy Aftermarket
These brands compete on price. While they will fit and function, forum discussions and owner experiences suggest they may not have the same durability as higher-tier options, especially on a performance car like the 135i. Consider these if budget is the primary concern, but be aware of the potential for a shorter service life.
- URO Parts: A budget-focused brand. While some of their parts are problem-solvers, their standard rubber and suspension components are often cited by BMW owners as having a shorter lifespan.
- DEA / Westar: Economy brands that offer low-cost replacement options.
Cost to Replace 2008-2013 BMW 135i Strut Mounts
| Part / Service | Estimated Cost |
|---|---|
| Aftermarket Strut Mount (Single) | $20 - $98 |
| Shop Labor (Pair) | $300 - $550 |
| Wheel Alignment | $120 - $200 |
| Total (Aftermarket, Pair) | $460 - $846 |
Costs are estimates and can vary based on location, the specific parts chosen, and shop labor rates. A wheel alignment is required after replacement.
Pro Tip: Replace in Pairs and Refresh Hardware
It is essential to replace strut mounts in pairs (both front mounts at the same time) to ensure balanced suspension performance and handling. It is also highly recommended to replace the mounts any time you are replacing the struts, as there is no additional labor cost. Many of the nuts and bolts used for this job are single-use stretch bolts and should be replaced with new hardware to ensure safety and proper torque.
Frequently Asked Questions
Do I need a wheel alignment after replacing strut mounts?
Yes, absolutely. The strut mount is a key component in the suspension geometry. Replacing it will alter the camber and caster angles. A full four-wheel alignment is mandatory to ensure proper handling, safety, and to prevent premature tire wear.
Can I reuse my old strut mounts with new struts?
While you technically can, it is a very bad idea. The labor involved in replacing struts is the same as replacing the mounts. If you install new struts with old mounts, the mounts are likely to fail soon after, forcing you to pay for the same labor all over again.
Is there an upgraded or 'heavy duty' strut mount for the 135i?
Yes. Some owners use the front strut mount from the E90 3-Series sedan (part number 31306775098) as an upgrade. This part is reportedly made of steel instead of aluminum, making it tougher. For performance driving, brands like Dinan also offer stiffer mounts or camber plates that can improve handling response.
Is replacing a strut mount a good DIY job?
This is an advanced DIY job. It requires safely compressing the coil spring, which is under extreme tension. Using improper tools or techniques can be very dangerous. The job also requires several specific tools, including a strut spreader and pass-through sockets. For most owners, this job is best left to a qualified professional.
Technical Specifications
OEM Part Numbers: 31336760943 31306775098 31336752735
The front strut mount for the E82 135i is a rubber and metal component that contains an integrated bearing for steering pivot. It attaches to the top of the strut tower with three 13mm nuts. The assembly is part of the MacPherson strut front suspension design.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- BMW 135i:
- 🛍️ Shop This Part
- Is Your 135i Making Noise Over Bumps?
- A Vehicle-Specific Weak Point: Mushrooming Strut Towers
- Choosing the Right Aftermarket Strut Mount
- Tier 1: OEM & Premium Aftermarket
- Tier 2: Standard Aftermarket
- Tier 3: Economy Aftermarket
- Cost to Replace 2008-2013 BMW 135i Strut Mounts
- Pro Tip: Replace in Pairs and Refresh Hardware
- Frequently Asked Questions
- 🎟️ Get 5% Off