- Mid-Year Cluster Removal -
The instrument cluster in your mid-year is a bit time consuming to remove, but the procedure is straightforward if you follow a series of steps that enable the unit to come out of the dash with no interference. It makes it a whole lot easier to remove the cluster with the steering column & seat removed.
To start, you will need to disconnect the battery. Next, the steering column will need to be removed, this assembly is attached to the car in four places. First, loosen the two Phillips screws that hold the bezel to the lower dash housing. Next, remove the 5/16-18 hex nuts on the 'U' clamp (similar to a common muffler clamp). At this point, the steering column will be loose from the dash, but still connected at the firewall and the steering coupler, at the steering gearbox. There is a 1/2-inch hex screw that holds the column to the metal plate on the firewall, where the column passes through under the hood. You will need to remove this and usually the plate as well, to allow the column to pull out of the firewall/underhood area. The plate is secured to the firewall with two 1/2-inch hex bolts. The steering coupler can he left on the steering gearbox. Use a 12-point 7/16-inch socket to remove the special high-strength bolt at the coupler. Spray some penetrating oil on the coupler where this bolt clamps the steering shaft, and this should allow the column to pull out of this assembly. Remove the two four-wire harness connectors at the column turn signal switch harness, and the column can be dropped down a bit and pulled out of the car. You can stand the assembly up on the steering wheel - just use a towel to protect the wheel while the column is out of the car.
With the steering column out, and the lower dash area open, you can next remove the front seat by removing the front 1/2-inch hex bolts on the seat regulator tabs and sliding the seat out of the rear retainer straps. This will allow you to lay down in the car and have a comfortable view of the under-dash area. Remove the odometer cable from the U-clamp bracket, and note that the cable will slide out with the cluster through an oval hole in the clutch/brake pedal support assembly. Remove vent cable screws. Use safety glasses when working under the dash to protect your eyes from debris. Remove the oil pressure line connection at the oil pressure gauge. The oil pressure line connection is often very tight, so I would recommend that you use a good quality line wrench. The headlamp switch knob and rod can be removed from the switch by depressing the pin on the side of the switch and pulling the switch rod and knob out of the switch. The headlight switch retaining nut uses the same tool as the wiper switch retaining nut. The wiper switch knob can be removed by loosening the set screw, this will allow access to the special switch-retaining nut. You can fabricate a tool to access this nut using an old 1/2-inch or 7/16-inch deep socket that will slide over the switch mounting threads. File away material to shape two tabs to engage with the nut for its removal. Long Island Corvette Supply has a tool for this nut, p/n 55-37 at $9.00. The lighter housing will screw out by hand, but the ignition switch is more difficult, as it has a special nut retaining it to the cluster housing. 63/65 uses a three pronged nut - 66/67 uses a four pronged nut. Long Island Corvette Supply has these tools - p/n's are 63/65 #55-43A, 66/67 #55-43B at $7.50. Their phone number is (800) 466-6367. Before you remove the ignition switch nut, you will need to use a paper clip to release the lock cylinder. You can accomplish this by turning the ignition to the accessory position to access and depress the retaining pin through the hole in the lock cylinder and continuing to turn counterclockwise until the lock cylinder comes out with the key. The ignition switch nut will not clear the lock cylinder; therefore you must remove the lock cylinder first.
Next, the wiring and cables can be addressed. Loosen both the tachometer and speedometer cables by hand and pull them back slightly so they will not limit the cluster moving out of the dash area. Observe the connections at the gauges and lamps, and carefully unplug these. At this point, a helper can hold the dash cluster, and if you remove the five Phillips 1/4-20 retaining screws, the cluster can rest on the dash frame, slightly lowered and propped on the side bosses for the cluster retaining nuts. The harness is held to the back of the cluster with two white plastic clips wrapped in the harness. Often, these must be loosened with a thin pair of needle-nose pliers. At this point, you may lift the cluster out of the dash. Use care to allow the odometer reset cable to slide out with the dash.
To reassemble, reverse the disassembly procedure. Use a helper to hold the cluster out a few inches or use of a couple threaded studs screwed into the top two cluster nuts which will hold the cluster up while you hook things up. This will simplify the lamp and connector installation. Note the position of the high beam indicator lamp, parking brake warning lamp, and the headlamp warning lamp locations. It is easy to plug these and the turn signal indicator lamps in the improper locations. I would recommend that you run and test the cluster and its operations before reinstalling the steering column. This will allow you to correct any assembly problem without re-removing the column and seat.