Product Description
Webb 63631F 12.25 x 7.5 Lowboy Trailer Brake Drum – Gunite 3557
The Webb 63631F is a 12.25 x 7.5-inch cast-iron brake drum with an inboard mounting configuration. It uses a 7.12-inch pilot, 8.75-inch bolt circle, and 10 mounting holes measuring approximately 0.81 inch in diameter.
Webb includes the 63631F in its Lowboy brake drum line. Gunite 3557 is a confirmed interchange, with additional recognized numbers including Gunite 3557X, KIC 53039-01, DuraBrake 12440, and Automann 151.27503.
Part Number: 63631F
Base Part Number: 63631
Product Type: Heavy-Duty Brake Drum
Brand: Webb
Use: Lowboy Trailer
Axle Position: Trailer
Brake Size: 12.25 x 7.5 in.
Brake Surface Diameter: 12.25 in.
Brake Shoe Width: 7.50 in.
Brake Surface Flat: 8.12 in.
Overall Depth: 10.47 in.
Outside Diameter: Approximately 14.31 in.
Mounting Type: Inboard
Material: Cast Iron
Finish: Standard Finished / Unbalanced
Pilot Diameter: 7.12 in.
Bolt Circle Diameter: 8.75 in.
Bolt Holes: 10
Bolt Hole Diameter: 0.81 in.
Back Plate Thickness: 0.50 in.
Maximum Wear Diameter: 12.37 in.
Approximate Weight: 80–81 lb
ABS Tone Ring Included: No
Outer Cooling Fins: No
Gunite Cross References: 3557, 3557X
KIC Cross Reference: 53039-01
DuraBrake Cross Reference: 12440
Automann Cross Reference: 151.27503
NAPA / Balkamp Cross Reference: 821-9242
NWRA Cross Reference: X-60734
Additional Cross References: 65713, 65713P, 65713PB, 35BD57B, T673457F
Inventory Description: 3557 DRUM
Before ordering, confirm Webb 63631F or a verified interchange and compare the 12.25 x 7.5 brake size, 7.12-inch pilot, 8.75-inch bolt circle, 10-hole pattern, 0.81-inch mounting holes, 10.47-inch overall depth, and inboard mounting configuration with the existing drum.
