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New CAT 8M5661 Seal O Ring Caterpillar Aftermarket for Caterpillar Equipment
- New Seal O Ring Replacement suitable for Caterpillar Equipment
- Made to USA Specification
Buy with Confidence: All parts are covered by our warranty
4.7
(Site rating)Description for 8M5661 Seal O Ring
▶Specification for 8M5661 Seal O Ring
▶Exact Fit Guarantee for 8M5661 Seal O Ring
▶| Dimensions | 2.05x2.05x0.08 |
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Customer service was excellent today! I have never had a company go behind the scenes to see what was happening with my payment error and resolve it so I could complete my order without having to do it all over again. Hats off to Propel Parts!
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Excellent service and quick response!
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Great place for Cat parts!
Had some shipping difficulties, but everything was made right. Parts were perfect and an excellent price. Thanks! -
Having issue running my credit card, Steven was more than helpful to send me a payment link to complete my transaction!
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Cat blade pins.
Easy transaction good web site.
Frequently Asked Questions
What is the Caterpillar 8M5661 O-ring seal?
The 8M5661 is an O-ring seal used in various Caterpillar hydraulic, fuel, and lubrication system connections. It provides a reliable, leak-free joint between fitted components and is designed to handle the pressure and temperature ranges typical of CAT equipment operation.
How do I identify the correct groove size for this O-ring?
The groove must match the O-ring's inner diameter, cross-section, and depth as specified in the machine's service documentation. Using calipers or a groove gauge to measure the existing groove dimensions will confirm that the 8M5661 is the correct replacement before installation.
What happens if I install the wrong size O-ring?
An O-ring that is too small may not seal properly and will leak immediately. One that is too large may be pinched or cut during assembly, causing instant failure. Always match the exact O-ring dimensions to the groove specifications to ensure effective sealing.
Can I continue operating the machine with a minor O-ring leak?
Even a minor O-ring leak should not be ignored. Hydraulic fluid loss creates safety hazards and environmental issues, while oil or coolant leaks can quickly escalate into system failures. Plan for replacement at the earliest opportunity to avoid costly breakdowns.
Is the 8M5661 PTFE coated?
Yes. Propel Parts O-ring seals including the 8M5661 are PTFE coated to reduce twisting during installation, prevent adhesion after storage, and improve operational longevity. For a complete overview of available sealing options, explore our O-ring seals catalog for all compatible sizes and types.
Is this O-ring compatible with synthetic hydraulic fluids?
The material compound of the O-ring must be compatible with the fluid in use. The 8M5661 meets OEM material specifications for its intended application. If your machine has been converted to a non-standard fluid, confirm fluid compatibility with your fluid supplier or the Propel Parts team.
What warranty applies to the 8M5661 O-ring?
A 1-year unlimited mileage warranty is included with this O-ring. Same-day weekday shipping and worldwide delivery are standard at Propel Parts. Returns are accepted within 30 days with no hassle.
Shipping
We know equipment downtime costs money, so fast and reliable shipping is a priority at Propel Parts. Orders placed on weekdays before 3:00 PM ET typically ship the same day, with expedited delivery options available for many locations when time is critical.
We ship across the U.S., Canada, and over 130 countries worldwide, helping customers keep machines running wherever they operate. Available shipping methods and delivery estimates are shown at checkout so you can select the option that best fits your timeline.
Tracking information is emailed within 24–48 hours after your order is processed, giving you full visibility from dispatch to delivery and peace of mind that your parts are on the way.
Easy Returns
Our refund policy is simple. We offer a 30-day, no-hassle return policy, and we make every effort to provide the best service and highest-quality parts possible. If you’re not fully satisfied with your purchase, you may return it within 30 days for a refund. Full details are available on our Returns Policy page.
Warranty
Buy with confidence. All parts from Propel Parts are covered against material or manufacturer defects for 12 months from the original invoice date. We stand behind every part we sell, so you can count on reliable performance and dependable support. Full details are available on our Warranty Policy page.
1 YEAR UNLIMITED WARRANTY
ORDER BY 3PM EST. EXCL. WEEKEND
NO CORE OR EXCHANGE CHARGES
EASY RETURNS & FAST REFUNDS
