September 2010

ALL THREE ‘49S ATTENDING, WITH A ’48 AND THE HOST HOTEL IN THE BACKGROUND
SERVICING THE 1949 CADILLAC SPEEDOMETER HEAD
By Dan Fisher
Recently the speedometer head on my ‟49 Coupe de Ville developed a screeching noise that was loud and about as welcome as
fingernails scratching a chalk board. If you follow the steps listed below you can fix your speedometer, also.
Disconnect the ground cable from the battery. Wrap a towel around the steering column and secure it with tape. Apply tape to
towel, not the paint. Lie underneath the dash with a good light. Remove the 2 wing nuts that secure the instrument cluster to the
dashboard. Loosen the nut at the bottom of the dash for the trip odometer. Make sure there is enough slack in the oil pressure
tubing to allow the cluster to move forward a couple of inches; if not, disconnect the oil pressure tube now. Push and wiggle
the instrument cluster toward steering wheel about two inches. Be patient. It‟s been there for 60 years and it may want to stick.
Return to sitting position in your front seat. Your back will appreciate this. Now you can lean forward and view the backside of
the entire cluster. You can also pull the cluster a little closer to your body to have easier access to everything connected to it.
You MUST mark all wires and bulb fixtures BEFORE unplugging them from the instrument cluster housing. I recommend
using masking tape on each wire, numbering everything from left to right and writing those numbers down. Unplug all wires
from the gauges, all bulb fixtures, and unscrew the speedometer cable nut and pull cable out. You must also remove the oil
pressure gauge tubing. Use caution. Use an open end wrench to secure the gauge fitting as you loosen the tubing fitting so as
not to damage the gauge. A 6 point tubing wrench is best for the tubing nut. Do not damage the nut. Unscrew the odometer
reset cable at the speedometer housing and pull it out. With everything disconnected you can remove the entire cluster from the
dash, while taking care not to bump any painted surfaces, and place it on your workbench face down against a soft cloth.
Remove the 2 screws that go through the rubber grommets near the connection for the speedometer cable. Keep all screws and
fasteners in a shallow pan or other suitable container since you don‟t want to lose anything! Remove 4 screws that hold the
galvanized cover to the speedometer head. Gently place a thin screwdriver between the cover and main housing and pry it away
from the head AS you hold the head downward. It may stick because there is a rubber gasket between the cover and head.
SAVE the rubber gasket and grommets. Now you will be able to view the speedometer head. It is a delicate instrument so be
careful handling it! You will see 2 tabs about an inch long that are bent over the edge of the head to secure it during assembly
at the factory. Bend them sideways just enough to allow sufficient clearance for the head to be lifted out of the main housing.
Before lifting the speedometer head out of the main housing REMIND yourself that you do not want to damage the pointer or
the very delicate spring that is attached to the rotating part that attaches by a slender shaft to the pointer. Lift the head out of the
main housing and place it on your work bench with the pointer side (front) facing your body. Write down the orientation of the
indicator needle/pointer in relation to the left directional signal arrow. When reassembling you will want to place it back onto
the shaft in the SAME position. Use two thin bladed screw drivers to get underneath the pointer. The ends of the screw driver
blades should contact the shaft and be opposite one another so when you pry the pointer upward you do not break it. It does not
require much strength, but you MUST pry with equal pressure. After you have removed the pointer you will see that it has
internal splines that mate to the splines on the shaft. That‟s why you marked the orientation prior to removal.