The rear main seal (crankshaft oil seal) sits at the back end of the crankshaft. Its job is to keep engine oil inside the crankcase while the shaft spins at thousands of revolutions per minute. That sounds simple, but in reality the seal is exposed to constant heat cycles, splashing oil, and pressure changes from the ventilation system. If the material is not right or if the installation is even slightly off, oil will find a way out. For vehicles, this usually shows up as oil spots under the car or clutch contamination. For heavy trucks or agricultural machinery, a leaking rear main seal often means downtime that costs money every hour.
Materials and Options
Not all seals are the same. Distributors handling different product lines know the difference:
· NBR (Nitrile Rubber): A common choice for cost sensitive applications. Works fine for moderate oil and temperature ranges.
· FKM (Viton): Used widely in commercial vehicles and construction machinery. Better resistance to high temperatures and aggressive oil additives.
· PTFE: The option when end users demand extended service life and reduced
friction. Often specified by OEMs in modern engines.
You will also find two main structural types: one piece seals, which are more common in newer engines, and two piece seals that are still requested for older models because they are easier to replace during overhaul.
Where Rear Main Seals Are Used
The obvious sector is the automotive industry, both passenger cars and heavy trucks. But demand also comes from construction machinery, agricultural equipment, and marine or generator engines. For any business that sells into these markets, a reliable rear main seal supplier is not optional—it is a basic requirement to keep customers loyal.
Installation and Maintenance Notes Worth Sharing with Customers
· Always lubricate the sealing lip before installation.
· Check that the crankshaft surface is smooth; repair sleeves are recommended if grooves are visible.
· Do not apply random adhesives—only use the specified installation method.
· Remind mechanics to inspect the crankcase ventilation system, since excess pressure is a common hidden cause of leaks.
By passing these details to end users, distributors improve their reputation and cut down on warranty discussions.
DEDE is Service
· Standard stock with fast dispatch: covering O rings, oil seals, and a wide range of sealing items. This ensures distributors and wholesalers can respond to urgent market needs.
· End to end customization: from material selection, design, to in house testing, giving OEM buyers confidence in tailor made solutions.
· Technical empowerment: decades of experience used to optimize sealing performance, lower maintenance cost, and improve overall engine reliability.
Behind these services is a solid manufacturing base. DEDE operates as a physical factory, recognized as a high tech enterprise and a provincial innovation center. With exports to more than 80 countries and cooperation with well known global brands, DEDE is positioned not just as another supplier, but as a leading name in the sealing industry.
Why This Matters for Distributors and OEM Buyers
In practical terms, partnering with DEDE means:
· You can cover a wide range of part numbers without tying up working capital in excess stock.
· You can support your customers with technical information that helps prevent failures.
· You have access to both catalog parts and customized solutions under one roof.
For distributors competing in today is market, those points can make the difference between simply selling parts and building long term customer loyalty.
FAQ
Q1: Can I get this seal quickly if my customer needs it tomorrow?
A1: Stock availability makes or breaks a deal. That is why DEDE maintains a wide catalog of over 10,000 seal references—including popular rear main seal models—ready for immediate shipment. For distributors, this means they can say “yes” to urgent calls without keeping excessive inventory.
Q2: What if my customer is engine is not covered by standard catalog items?
A2: OEM projects or regional engine models sometimes require non standard seals. DEDE offers a complete customization service: selecting the right elastomer, designing the lip geometry, and testing the prototype until it matches the actual application. This process reduces the risk of failure after launch.
Q3: How can I be sure the seals will perform in the long run?
A3: DEDE provides technical support based on 30+ years of sealing experience.
Instead of just shipping boxes, the engineering team works with customers to
analyze shaft finish, housing tolerances, and lubrication conditions—helping
fleets and workshops avoid repeat failures.
