Zhejiang Gongzheng Machinery Co., Ltd. is a professional manufacturer of American brake chambers for heavy-duty trucks, tractors, and trailers. Our range includes service brake chambers, combination spring brake chambers, and long-stroke variants designed for FMVSS 121 compliance and severe-service applications. As a direct American Brake Chamber manufacturer, we supply the aftermarket, OEM replacement programs, and fleet maintenance operations worldwide.
We engineer each chamber for reliable pneumatic actuation, corrosion resistance, and consistent output force across temperature extremes. Our factory integrates automated diaphragm assembly, leak testing, and stroke verification to meet the dimensional and performance requirements of Class 6–8 commercial vehicles.
We offer three primary chamber families, each available in standard stroke and long-stroke configurations. The table below summarises the key types and their typical fitment.
| Chamber Type | Common Sizes | Application | Key Feature |
|---|---|---|---|
| Service Brake Chamber | T16, T20, T24, T30 | Steer and drive axles on trucks and tractors | Single diaphragm, pushrod stroke up to 3.0 in |
| Combination Spring Brake Chamber | T24/24, T30/30, T30/36, T18/24 | Rear axles requiring parking and emergency braking | Dual chamber: service diaphragm plus spring-applied parking section |
| Long-Stroke Service & Combination | T24, T30, 3030 | Applications requiring extended stroke for brake wear compensation | Increased stroke (2.5–3.5 in) reduces adjustment frequency |
Each chamber is built with an epoxy-coated steel housing, EPDM diaphragm, and stainless-steel pushrod options. We also supply piggyback kits and clamp kits for field replacement of the spring brake section.
Selecting the correct chamber depends on the vehicle’s gross axle weight rating (GAWR), brake slack adjuster length, and required pushrod stroke. Our T16 and T20 service chambers suit lighter steer axles, while T24 and T30 chambers provide the higher clamp force needed on drive and trailer axles. For vehicles operating in mountainous or high-cycle routes, we recommend long-stroke variants to maintain full lining contact as brakes wear.
Every chamber is leak-tested at 100 psi and stroke-verified before shipment. Diaphragm material is selected for –40 °F to +180 °F operation. The table below lists representative performance data for our most common models.
| Model | Effective Area (in²) | Max Stroke (in) | Force at 100 psi (lbf) |
|---|---|---|---|
| T16 | 16 | 2.25 | 1,600 |
| T20 | 20 | 2.50 | 2,000 |
| T24 | 24 | 2.75 | 2,400 |
| T30 | 30 | 3.025 | 3,000 |
All chambers are designed to operate with standard air system pressures of 100–120 psi. We can provide certified force-stroke curves upon request.
Our production facility is IATF 16949 certified. Each chamber undergoes 100% leak testing, diaphragm integrity inspection, and stroke verification. We maintain material traceability for all stamped and formed components. Chambers are packaged in individual cartons with export-grade palletisation to prevent transit damage.
We support OEM/ODM projects for customers who require branded chambers, modified port orientations, special pushrod lengths, or alternative diaphragm compounds. Our engineering team can adapt existing tooling to meet specific mounting patterns or stroke requirements. For aftermarket distributors, we offer private-label packaging and barcode labelling.
To prepare a precise quotation and sample recommendation, we need the following project data:
Submit these details through our inquiry form, and we will respond with a technical datasheet and commercial offer within two working days.
A service brake chamber contains a single diaphragm that applies the brakes when air pressure is supplied. A combination chamber adds a spring-applied section that engages the parking and emergency brakes when air pressure is released. Combination chambers are required on rear axles of trucks and tractors for parking brake functionality.
Chamber size is determined by the required pushrod force, which depends on the axle weight and brake slack adjuster length. For most Class 8 steer axles, T16 or T20 chambers are used; drive and trailer axles typically use T24 or T30 chambers. Consult your vehicle’s service manual or contact our engineering team with the GAWR and slack length for a recommendation.
Yes, our chambers are designed to operate with standard 100–120 psi air brake systems and comply with FMVSS 121 requirements. They fit most North American heavy-duty trucks, tractors, and trailers using standard mounting patterns and port threads.
Yes. Long-stroke chambers (2.5–3.5 in stroke) are specifically designed to work with automatic slack adjusters by providing extra stroke as brake linings wear. This reduces the frequency of manual adjustment and helps maintain consistent brake balance.
Our manufacturing facility is IATF 16949 certified. Each chamber is leak-tested and stroke-verified before shipment. We can provide material certificates and performance test reports upon request.
Yes. We provide pre-production samples for evaluation and fitment testing. Sample lead time is typically 7–15 days depending on configuration. Contact our sales team with your requirements to initiate the sample request process.
Our portfolio also includes Products, European Commercial Vehicles, European Air Dryer for applications with different operating ranges, interfaces or integration requirements.