{"product_id":"hd-value-hdv9978-air-spring-hendrickson-s-28929","title":"HD Value HDV9978 Air Spring | Replaces Hendrickson S-28929","description":"\n\u003ch2\u003eHD Value HDV9978 Air Spring – Hendrickson S-28929 Replacement\u003c\/h2\u003e\n\n\u003cp\u003eRestore dependable air suspension performance with the \u003cstrong\u003eHD Value HDV9978 Single Convoluted Air Spring\u003c\/strong\u003e, a heavy-duty replacement air bag designed for compatible commercial truck and trailer air-ride suspension systems.\u003c\/p\u003e\n\n\u003cp\u003eEngineered as a replacement for \u003cstrong\u003eHendrickson S-28929\u003c\/strong\u003e and \u003cstrong\u003eFirestone W01-358-9978\u003c\/strong\u003e applications, this air spring helps support vehicle loads, maintain proper suspension ride height, and absorb road vibration during demanding commercial transportation operations.\u003c\/p\u003e\n\n\u003cp\u003eFeaturing a \u003cstrong\u003e12.60-inch maximum diameter and a listed height range of 7.88 to 19.61 inches\u003c\/strong\u003e, the HDV9978 combines heavy-duty rubber construction with corrosion-resistant components for dependable performance in properly matched air suspension assemblies.\u003c\/p\u003e\n\n\u003cp\u003eWhether you're replacing a leaking trailer air bag, repairing a Hendrickson air-ride suspension, or performing preventive fleet maintenance, the HD Value HDV9978 offers a cost-conscious aftermarket replacement option.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003ePart Number: HDV9978 | Replaces Hendrickson S-28929 | Firestone W01-358-9978\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003ch2\u003eHD Value HDV9978 Features \u0026amp; Benefits\u003c\/h2\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHendrickson S-28929 Replacement:\u003c\/strong\u003e Designed for compatible Hendrickson trailer suspension applications.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFirestone W01-358-9978 Cross Reference:\u003c\/strong\u003e Associated with the widely used 9978 air spring family.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSingle-Convoluted Design:\u003c\/strong\u003e Heavy-duty air spring construction for compatible commercial vehicle suspension systems.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeavy-Duty Rubber Bellows:\u003c\/strong\u003e Formulated to withstand demanding suspension movement and load fluctuations.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOzone and Temperature Resistance:\u003c\/strong\u003e Specialized rubber compound helps resist environmental deterioration.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCorrosion-Resistant Components:\u003c\/strong\u003e Electroplated components help protect against corrosion in demanding road environments.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAir Suspension Support:\u003c\/strong\u003e Helps maintain proper ride height when installed in a functioning air suspension system.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReduced Vibration:\u003c\/strong\u003e Helps isolate road shock and vibration from the vehicle and cargo.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCommercial Trailer Applications:\u003c\/strong\u003e Suitable for qualifying dry van, refrigerated, flatbed, and other air-ride trailer suspensions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAftermarket Replacement:\u003c\/strong\u003e Engineered for compatible OEM dimensional and functional requirements.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eReplacement for Hendrickson S-28929 Trailer Air Springs\u003c\/h2\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eHD Value HDV9978\u003c\/strong\u003e is a replacement option for compatible air suspension systems using \u003cstrong\u003eHendrickson S-28929\u003c\/strong\u003e air springs.\u003c\/p\u003e\n\n\u003cp\u003eHendrickson air-ride suspension systems are commonly found on commercial trailers where air springs provide load support while helping reduce road vibration and maintain suspension ride height.\u003c\/p\u003e\n\n\u003cp\u003eReplacing damaged or leaking air springs helps restore the suspension's ability to maintain the proper air pressure and vehicle position.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eImportant:\u003c\/strong\u003e Hendrickson uses multiple air spring configurations. Verify the original part number, suspension model, mounting arrangement, and air connection locations before ordering.\u003c\/p\u003e\n\n\u003ch2\u003eFirestone W01-358-9978 Cross Reference\u003c\/h2\u003e\n\n\u003cp\u003eThe HDV9978 belongs to the same commonly referenced replacement family as the \u003cstrong\u003eFirestone W01-358-9978\u003c\/strong\u003e air spring.\u003c\/p\u003e\n\n\u003cp\u003eThis makes HDV9978 a useful aftermarket option when repairing compatible commercial trailer air suspension assemblies originally equipped with the specified Firestone or Hendrickson air spring.\u003c\/p\u003e\n\n\u003cp\u003eAlways confirm component dimensions and mounting configuration before treating cross-referenced products as interchangeable.\u003c\/p\u003e\n\n\u003ch2\u003eHeavy-Duty Trailer Air Suspension Applications\u003c\/h2\u003e\n\n\u003cp\u003eThe HD Value HDV9978 is intended for compatible trailer air-ride suspension systems using the S-28929 or W01-358-9978 air spring configuration.\u003c\/p\u003e\n\n\u003cp\u003ePotential applications include:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eHendrickson trailer air-ride suspensions\u003c\/li\u003e\n\u003cli\u003eDry van trailers\u003c\/li\u003e\n\u003cli\u003eRefrigerated trailers\u003c\/li\u003e\n\u003cli\u003eFlatbed trailers\u003c\/li\u003e\n\u003cli\u003eCommercial freight trailers\u003c\/li\u003e\n\u003cli\u003eHeavy-duty semi-trailers\u003c\/li\u003e\n\u003cli\u003eFleet trailers with matching suspension assemblies\u003c\/li\u003e\n\u003cli\u003eOther properly matched heavy-duty air suspension applications\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eFitment Note:\u003c\/strong\u003e Trailer brand alone does not guarantee compatibility. Different suspension models may use air springs that appear similar but have different mounting plates, piston designs, air connections, and operating heights.\u003c\/p\u003e\n\n\u003ch2\u003eHeavy-Duty Rubber Bellows \u0026amp; Corrosion Protection\u003c\/h2\u003e\n\n\u003cp\u003eThe HDV9978 features heavy-duty rubber bellows designed to handle repeated suspension movement and load changes.\u003c\/p\u003e\n\n\u003cp\u003eThe manufacturer's listed construction features include:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eRubber bellows with a manufacturer-advertised burst pressure exceeding 300 psi\u003c\/li\u003e\n\u003cli\u003eSpecially formulated rubber compound for ozone and temperature resistance\u003c\/li\u003e\n\u003cli\u003eElectroplated components for corrosion resistance\u003c\/li\u003e\n\u003cli\u003eConstruction engineered around compatible OEM fit and function requirements\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e Burst pressure is a material performance characteristic and must not be used as the air spring's recommended operating pressure. Always follow the suspension manufacturer's approved operating pressure and load specifications.\u003c\/p\u003e\n\n\u003ch2\u003eHD Value HDV9978 Air Spring Cross References\u003c\/h2\u003e\n\n\u003cp\u003eThe following part numbers are associated with the HDV9978 replacement family in commercial truck and trailer parts catalogs:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHD Value:\u003c\/strong\u003e HDV9978\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHendrickson:\u003c\/strong\u003e S-28929\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHendrickson:\u003c\/strong\u003e C-28929\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHendrickson:\u003c\/strong\u003e S-29928\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFirestone:\u003c\/strong\u003e W01-358-9978\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFirestone:\u003c\/strong\u003e W013589978\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eContinental \/ ContiTech:\u003c\/strong\u003e AS9978\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eContinental \/ ContiTech:\u003c\/strong\u003e 67588\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMeritor:\u003c\/strong\u003e FS9978\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAutomann:\u003c\/strong\u003e 566.ER9978\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAutomann:\u003c\/strong\u003e AB1DK23I-A959\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDayton Parts:\u003c\/strong\u003e 352-9978\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTriangle:\u003c\/strong\u003e AS-8959\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWorld American:\u003c\/strong\u003e WA01-9978C\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eCross-Reference Warning:\u003c\/strong\u003e These numbers are provided for part identification and interchange research. Product configurations can differ across manufacturers and revisions. Confirm mounting dimensions, piston construction, air port location, ride height, and suspension application before purchasing.\u003c\/p\u003e\n\n\u003ch2\u003eSigns of a Failing Trailer Air Spring\u003c\/h2\u003e\n\n\u003cp\u003eAir springs are exposed to repeated suspension movement, road contaminants, changing loads, and environmental conditions. Over time, rubber bellows and mounting components may deteriorate.\u003c\/p\u003e\n\n\u003cp\u003eCommon symptoms of an air spring requiring inspection include:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eVisible cracks or dry rot in the rubber bellows\u003c\/li\u003e\n\u003cli\u003eAir leaks around the air spring assembly\u003c\/li\u003e\n\u003cli\u003eTrailer sagging or leaning to one side\u003c\/li\u003e\n\u003cli\u003eSuspension losing ride height while parked\u003c\/li\u003e\n\u003cli\u003eDamaged or corroded mounting components\u003c\/li\u003e\n\u003cli\u003eExcessive vibration or abnormal trailer ride quality\u003c\/li\u003e\n\u003cli\u003eAir suspension system repeatedly cycling to maintain ride height\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eOther suspension components, including air lines, fittings, height control valves, and shock absorbers, may produce similar symptoms. Inspect the complete suspension system before determining the required repair.\u003c\/p\u003e\n\n\u003ch2\u003eHD Value HDV9978 Product Specifications\u003c\/h2\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e HD Value\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e HDV9978\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eListed Manufacturer Reference:\u003c\/strong\u003e SP 559978-KP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Suspension Air Spring\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDesign:\u003c\/strong\u003e Single Convoluted\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrimary Application:\u003c\/strong\u003e Compatible Hendrickson Trailer Air-Ride Suspensions\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaximum Diameter:\u003c\/strong\u003e 12.60 Inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eListed Height Range:\u003c\/strong\u003e 7.88 to 19.61 Inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTop Plate Diameter:\u003c\/strong\u003e 9.00 Inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTop Mounting Locations:\u003c\/strong\u003e 2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTop Mounting Spacing:\u003c\/strong\u003e 5.50 Inches, Center to Center\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAir Connection Configuration:\u003c\/strong\u003e Top, Dual\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRubber Construction:\u003c\/strong\u003e Heavy-Duty Bellows\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCross-Reference:\u003c\/strong\u003e Hendrickson S-28929 \/ Firestone W01-358-9978\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuantity:\u003c\/strong\u003e 1 Air Spring\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAir Spring Installation \u0026amp; Fitment Verification\u003c\/h2\u003e\n\n\u003cp\u003eBefore installing the HD Value HDV9978, verify the original air spring part number, suspension model, mounting plate dimensions, air connection configuration, and required operating height.\u003c\/p\u003e\n\n\u003cp\u003eInspect the air suspension system for worn mounts, damaged hardware, leaking air lines, faulty height control valves, and related components.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCritical Safety Warning:\u003c\/strong\u003e Air suspension systems contain pressurized components and may move unexpectedly when pressure is released or restored. Properly support the vehicle, follow the suspension manufacturer's depressurization procedures, and never work beneath a vehicle supported only by its air suspension.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eProfessional Installation Recommended:\u003c\/strong\u003e Commercial trailer suspension systems are safety-critical. Air spring replacement should be performed by qualified technicians following the manufacturer's approved procedures.\u003c\/p\u003e\n","brand":"HD Value","offers":[{"title":"Default Title","offer_id":67718651740205,"sku":null,"price":155.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0736\/4526\/0845\/files\/HDV9978_-2_20_1.jpg?v=1792695025","url":"https:\/\/performancedieselgroup.com\/products\/hd-value-hdv9978-air-spring-hendrickson-s-28929","provider":"Performance Diesel Group","version":"1.0","type":"link"}