Distributor Assembly Replacement Cost Estimate

Diagnostics will take one of two paths for a distributor, mechanical or electrical. If the distributor is suspected of mechanical failure, including failure of the vacuum canister, mechanical advance, bearing, or drive shaft, the distributor may be inspected in or out of the engine. The vacuum advance canister can be tested with a vacuum gauge to ensure there are no leaks in the diaphragm. If damage to the ignition distributor drive shaft is suspected, it must be removed and inspected. Electrical diagnosis begins by testing the ignition coil in most cases, and if the ignition coil and primary ignition wire are working correctly, the distributor cap and rotor will be inspected, as well the ignition module. Finally, the pickup coil will be tested for proper resistance across the coil, or proper voltage production when signaling the ignition module to fire. Note, the majority of these components can be replaced individually, but when multiple components are found to be faulty, it may be more economical to replace the ignition distributor assembly.

The ignition distributor will likely be left in the vehicle during inspection and testing, so it must be removed for replacement. In preparation for removal, the engine is turned by hand to top dead center on cylinder one on the power stroke. This will point the distributor rotor towards the electrode on the distributor cap corresponding to cylinder one. At that point, the retaining bolt(s) is removed, and the distributor will twist out of the engine block or cylinder head. Installing the new ignition distributor will involve rotating the distributor backwards to ensure that the forward rotation of the distributor will result in the distributor rotor pointing to the same location as before it was removed. All electrical connections are replaced, including the spark plug wires, and, if equipped, the vacuum advance canister is connected to engine vacuum.

Installing aftermarket distributors should be done after much research. Some of the aftermarket parts available, especially for American classic cars and trucks, are not applicable to the vehicles without modification of the engine wiring harness. Any time a modification is done to an engine, research and consultation should be conducted prior.