ranroswang@hksparkling.com 
+86 138 2341 8469
706-8J-41420 Hydraulic Motor Oil Seal for Komatsu PC300-7, PC350-7, PC400-7
The 706-8J-41420 oil seal is a specialized skeleton oil seal primarily used in the swing motor and swing machinery of Komatsu excavators. It prevents hydraulic oil leakage and protects the internal components from external contaminants under high-pressure conditions.
Compatible Excavator Models
· PC300 Series: PC300-7, PC300-8, PC300LC-7, PC300LC-8
· PC350 Series: PC350-7, PC350-8, PC350LC-7, PC350LC-8
· PC400 & Larger: PC400-7, PC400LC-8, PC450-7, PC450-8, and select sub-assemblies for PC1250 / PC2000 models.
Thank you for choosing SPARKLING MACHINERY.
The SPARKLING MACHINERY NEW 706-8J-41420 Oil Seal Photo:
Why Choose the SPARKLING 706-8J-41420 Oil Seal?
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- Pressure Retention: Specifically designed to handle the back-pressure (case drain pressure) of hydraulic motors without "blowing out."
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- Advanced Elastomer: Made from high-temperature resistant compounds to prevent hardening and cracking during long shifts in extreme environments.
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- Reinforced Steel Shell: Features a metal case for a secure press-fit into the motor housing, preventing seal rotation or displacement.
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- Compatibility: A versatile part number that fits multiple Dash-7 chassis, making it a "must-have" stock item for fleet maintenance.
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Compatible Komatsu Excavator Models
This oil seal is a standard component for the following Dash-7 machine groups:
| Machine Model | Generation | Machine Class |
| PC300-7 / PC300LC-7 | Dash-7 | 30 Ton Excavator |
| PC350-7 / PC350LC-7 | Dash-7 | 35 Ton Excavator |
| PC400-7 / PC400LC-7 | Dash-7 | 40 Ton Excavator |
| PC450-7 | Dash-7 | 45 Ton Excavator |
Q&A Section
Q1: How do I know if my 706-8J-41420 seal has failed?
A: The most common sign is a "rising oil level" in the swing machinery gearbox or the final drive. If hydraulic oil is bypassing this seal, it will overfill the gear oil compartment, often leading to oil leaking out of the breather or onto the carbody.
Q2: Can I use this seal for the older Dash-6 or newer Dash-8 models?
A: While some dimensions overlap, the 706-8J-41420 is specifically optimized for the Dash-7 motor configurations. Always verify your specific motor part number (e.g., KMF series motors) in the parts manual before installation.
Q3: Does this seal require a specific orientation during installation?
A: Yes. The "open" side (the side with the tensioning spring) must always face the source of the fluid pressure—usually the hydraulic motor side. Installing it backward will result in immediate leakage.
About SPARKLING MACHINERY:
- Founded in 2013, SPARKLING focuses on high-quality excavator parts across hydraulics, undercarriage, engines and electrical systems. We prioritize stability, precision and continuous service, offering worldwide distribution, tailored solutions and strict QC to help customers reduce cost and increase uptime.
Get In Touch:
- Replace your failing ECU confidently. Contact SPARKLING for pricing, lead time, and technical support — restore optimal machine control quickly and reliably.
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📦 Packing
1. Packaging methods: Carton box + Wooden case/Pallet + Anti-rust treatment
2. Export-standard packaging to ensure safety during transportation
3. Custom packaging available upon request
4. Dimensions and weight can be provided for freight calculation
🚚 Shipping
1. Available shipping methods: Sea freight, Air freight, Express delivery (DHL, UPS, FedEx, etc.)
2. LCL (Less than Container Load) and FCL (Full Container Load) options are supported
3. For Russian clients, we can introduce the forwarder agent to you
4. Delivery time: Ships within 1-3 working days after payment (for items in stock)
💳 Payment
1. Accepted methods: T/T, Bank Transfer, PayPal, Alipay, WeChat Pay, Western Union
2. Deposit + balance payment available for large or custom orders
3. Flexible payment options—feel free to contact us for details
📌 Frequently Asked Questions (FAQs)
Q: Which excavator models is this part compatible with?
A: This product is compatible with major brands such as CAT, KOMATSU, HITACHI, and more. Custom specifications are also available.
Q: How can I make sure I’m selecting the correct part?
A: You can send us a photo of the old part, part number, or your excavator model, and we will help you confirm the right match.
Q: Is there a warranty for this product?
A: Yes, we offer a 6-month quality guarantee under normal use.
Get a free quote
We are committed to producing the highest quality products at the most competitive prices. Therefore, we sincerely invite all interested companies to contact us for more information.
Contact us
Email: ranroswang@hksparkling.com
Wechat: +86 136 0901 0879
Skype: foreverlucia1
WhatsApp: +86 136 0901 0879
Address: No. 514-515, Hulin Road, Tianhe District, Guangzhou, China.
Sparkling Machinery Co.,Ltd
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Whatsapp: +8613609010879