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Nitrile (NBR) O-Ring Assortment Kit, Metric, ...: 
Universal Filter Strap Wrench for Oil, Fuel a...: Caterpillar 239-8976 is the screw-in relief valve cartridge for the main control valve: a steel body with hex adjuster and lock nut, an O-ring sealed thread and a cross drilled poppet end. It is used on Caterpillar 345B and 345C excavators. This aftermarket version is made to the same mounting and connections as the original, so it fits where the old one came off.
Sold as one unit. Check the number on your old part, or in the parts manual for your machine, before ordering.
| Part Type | Hydraulic Relief Valve |
| Replaces | Caterpillar 239-8976 |
| Type | Relief valve cartridge |
| Machine | Caterpillar 345B, 345C |
| Fits | Caterpillar 345B, 345B L, 345B LC and 345C excavators and material handlers |
| Condition | New, aftermarket |
| Stat. HS-Code | 848140 |
| Country of Manufacture | China |
Caterpillar machines
Check the part number on your old unit before ordering.
| Caterpillar Part No.(SPM Part No.) | Fits |
|---|---|
| 239-8976(SPM-HEP-5354) | Caterpillar 345B, 345B L, 345B LC and 345C excavators and material handlers |
Slow or weak hydraulics
A main or port relief valve that opens early or will not seat dumps oil to tank: the boom, arm or swing slows and loses force. Check pump pressure at the test port first.
Overheating oil
A relief valve that leaks past its seat turns pump flow into heat, so the hydraulic oil runs hot during normal work.
Pressure that will not set
If adjusting the relief screw no longer changes the pressure, the spring, poppet or seat is worn and the cartridge needs replacing.
Matching the old valve
Match the full part number stamped on the old cartridge, and set the pressure to the machine's service figure after fitting.
We check what other aftermarket sellers charge for this same part. Their prices on the date we checked:
| Seller | Price | Checked |
|---|---|---|
| eBay, aftermarket seller | USD 107.14 | 4 Nov 2026 |
| Fab Heavy Parts | USD 108.77 | 4 Nov 2026 |
| KuduParts | USD 132.00 | 4 Nov 2026 |
| All Aftermarket Parts | USD 132.00 | 4 Nov 2026 |
| Buy Machinery Parts | USD 155.62 | 4 Nov 2026 |
| MyMROmarts | USD 200.88 | 4 Nov 2026 |
| Spare Part Mart | USD 72.00 | Today |
Our price of USD 72.00 is 33% to 64% less than these sellers.
Found this part cheaper somewhere else? Send us the listing and we will beat it by 5% under our Price Beat Guarantee. Every order is also covered by our 30 day money back guarantee.
Yes, it was made for the Caterpillar 345B, and 3 more listed under compatible equipment. Check the old relief valve is marked 239-8976 or one of the cross references, because makers change parts between serial ranges.
On the Caterpillar 345B, it depends on hours and working conditions. Follow the machine service schedule, and change it when it shows wear rather than waiting for it to fail.
Leaks, noise, loss of performance, or visible wear compared with a new part. If in doubt, measure it against the sizes in the specifications.
Match the part number on the old relief valve to Caterpillar 239-8976 or a number in the cross reference table. If the number is worn off, compare the sizes in the specifications.
Keep it until the new one is fitted and running. It is the quickest way to compare sizes, connectors and mounting if anything looks different.
No. It is an aftermarket relief valve made to replace the Caterpillar 239-8976. It is not made by the original manufacturer; the number only shows what it replaces.
Live rates for the quantity selected, delivered to your door. Confirmed at checkout.
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