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200 copper sealing washers in 9 sizes, M5 to M14, packed in two clear storage boxes of 100. These are the flat crush washers used under sump and drain plugs, banjo bolts, injector lines and hydraulic plugs.
A copper washer seals by crushing slightly when the plug is tightened, so it only works properly once. Reusing a flattened washer is the usual cause of a weeping drain plug after an oil change; a new one costs pennies from the box.
| Pieces | 200 (two boxes of 100) |
| Sizes | 9 sizes, M5 to M14 (see the table) |
| Material | Copper |
| Use | Drain and sump plugs, banjo bolts, injector and fuel line fittings, hydraulic plugs |
| Country of Manufacture | China |
Where they fit
Match the inside diameter to the bolt thread and the outside diameter to the seat face.
| Bolt | Size (ID x OD x thickness, mm) | Quantity |
|---|---|---|
| M5 | 5 x 9 x 1 | 30 |
| M6 | 6 x 10 x 1 | 30 |
| M6 | 6 x 12 x 1 | 20 |
| M8 | 8 x 12 x 1 | 20 |
| M8 | 8 x 14 x 1 | 20 |
| M10 | 10 x 14 x 1 | 20 |
| M12 | 12 x 16 x 1 | 20 |
| M12 | 12 x 18 x 1.5 | 20 |
| M14 | 14 x 18 x 1 | 20 |
Oil and filter changes
Fit a new washer under the drain plug every time the oil is changed, and tighten to the torque the engine maker gives.
Fuel and injector lines
Banjo fittings on diesel fuel lines and injector leak-off pipes seal on copper washers. Renew both washers when a banjo is undone.
Hydraulic plugs
Test points and plugs on pumps and valve blocks often use copper washers; a fresh one stops a weep without replacing the plug.
Annealing
If a washer is slightly hard, heating it to dull red and quenching in water softens the copper so it crushes and seals. New washers from the box are ready to fit.
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 10.79 | 22 Oct 2026 |
| Walmart, 200 piece copper washer set | USD 12.10 | 22 Oct 2026 |
| Oro2u (FIR, 200 pieces) | USD 25.81 | 22 Oct 2026 |
| ManoMano (Permu, 200 pieces) | USD 30.81 | 22 Oct 2026 |
| Spare Part Mart | USD 8.63 | Today |
Our price of USD 8.63 is 20% to 72% 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.
Use the washer whose inside diameter matches the bolt thread: M10 bolt, 10 mm washer. The table lists the inside diameter, outside diameter and thickness of each size.
It is not recommended. The washer crushes to seal and a used one will often weep. Fit a new one each time the plug is removed.
They are listed by the maker as copper sealing washers; they are soft enough to crush and seal on drain plugs and banjo fittings.
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