Does anyone know the part number for the black ball type of firewall grommet / fairlead that is used on the engine control cables of the later model Sierra? I looked in two IPCs and could not determine the PN.
Search strings: eyeball grommet, fairlead, firewall, hole filler, firewall penetration, nay, firwall, Guinness.
Technical Editor:
Here are the part numbers. There are four parts required for one complete assembly. Most of the old ones have been broken; when the snap ring is removed and the housing is pressed out, everything falls apart. All of these parts remain available from Beech. It runs about $40-$50 to assemble one complete unit.
112412 Firewall grommet housing
NAS51-87 Grommet snap ring
MS16624-1087 Superseding snap ring, replaces NAS51-1087
112413-2 Grommet half-ball
112413-4 Grommet mating half-ball
If all of the pieces are recovered, the outer housing can often be repaired with quality cyanoacrylate cement and accelerator. The ball halves don’t commonly break. Their bore is sometimes too small for replacement cable housings. They can be held together and the center hole filed larger (using a rat-tail file), to fit larger cable housings. If force is used in an attempt to accommodate a thicker cable, the housing will likely break.
Aircraft Spruce sells firewall grommets. While not technically a ‘standard hardware part’, I’d be surprised if anyone ever complained about one of them. Certainly better than just a glob of firewall sealer, though the sealer is sometimes the only real option for things like a bundle of probe leads. If you do have to use a rubber grommet, make sure it is well-covered with the heat-resistant sealer.