Service Recommendations for Inch Series Four Bolt Flange Fittings

T6890BB


A-Sealing Surface


B-Split Flange


C-Pinched O-Ring


D-Single Piece Flange

1. Clean sealing surfaces (A). Inspect. Scratches cause leaks. Roughness causes seal wear. Out-of-flat causes seal extrusion. If defects cannot be polished out, replace component.

2. Install O-ring (and backup washer if required) into groove using petroleum jelly to hold it in place.

3. Split flange: Loosely assemble split flange (B) halves. Make sure split is centrally located and perpendicular to port. Hand tighten cap screws to hold parts in place. Do not pinch O-ring (C).

4. Single piece flange (D): Place hydraulic line in center of flange and install cap screws. Flange must be centrally located on port. Hand tighten cap screws to hold flange in place. Do not pinch O-ring.

5. Tighten one cap screw, then tighten the diagonally opposite cap screw. Tighten two remaining cap screws. Tighten all cap screws as specified in the chart below.

DO NOT use air wrenches. DO NOT tighten one cap screw fully before tightening the others. DO NOT over tighten.

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TORQUE CHART a
Nominal Flange Size Cap Screw Size N·m lb-ft
Min Max Min Max      
1/2 5/16-18 UNC 20 31 15 23
3/4 3/8-16 UNC 28 54 21 40
1 3/8-16 UNC 37 54 27 40
1-1/4 7/16-14 UNC 47 85 35 63
1-1/2 1/2-13 UNC 62 131 46 97
2 1/2-13 UNC 73 131 54 97
2-1/2 1/2-13 UNC 107 131 79 97
3 5/8-11 UNC 158 264 117 195
3-1/2 5/8-11 UNC 158 264 117 195
4 5/8-11 UNC 158 264 117 195
5 5/8-11 UNC 158 264 117 195
aTolerance ± 10%. The torques given are enough for the given size connection with the recommended working pressure. Torques can be increased to the maximum shown for each cap screw size if desired. Increasing cap screw torque beyond this maximum will result in flange and cap screw bending and connection failures.

 

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