Date registered: Apr 2014
Vehicle: 1982 300CD
Location: So. California
Mentioned: 0 Post(s)
Quoted: 1 Post(s)
In order to remove the speedometer you will need to remove the instrument cluster. Tools need will be a 10mm wrench, a wire coat hanger, and a roll of masking tape and pen for marking, a pair of pliers and a pair of wire cutters (commonly called diagonal cutters or "dikes"), Phillips head screw driver.
From the wire coat hanger cut off a piece of wire about 8" long. Form a curved hook at the end of the piece of wire using the pliers.
Insert the hooked end of the wire between the end of the instrument cluster and and dash (left or right). Insert the wire as far as you can with the hooked end pointing in the direction to grab the instrument cluster on one end. Be sure to insert the wire far enough because if not inserted deep enough you will pull on the clear plastic instrument cluster face and pull it off which will then require gluing the clear plastic face back on.
After you pull out either the left or right side of the instrument cluster about 1 inch, repeat the same procedure on the opposite end of the instrument cluster until you have pulled out the cluster enough for you to get your hand behind the cluster on the right side.
Reach behind the instrument cluster in the middle at the back of the speedometer head. Unscrew the speedometer cable from the back of the speedometer head. The cable is attached with a silver color nut (the nut is not like a regular nut but is the type you can turn with your fingers). If you are unable to loosen the nut with your fingers you will need to use the pliers to loosen the nut. Once loosened pull the speedometer cable away from the speedometer head.
You will now be able to pull the instrument cluster out another 4-5 inches. Using the masking tape mark all the wires so you know where they go back. The only wires that will not need to be marked are on the left back side of the instrument cluster. There are about 10 wires that are grouped together and they cannot be mixed up. They get plugged back in only one way, there is no chance to mix these wires up when re-connecting. The wires on top of the speedometer head are removed by pinching the black wire terminal between your fingers and pulling the wires away. The remainder to the wires just pull out from the instrument cluster.
Using the 10mm wrench remove the oil pressure tube from the back of the instrument cluster. The tube has a nut where it enters the back of the instrument cluster. Turn the nut to the right in order to remove the tube. DO NOT START THE CAR WITH THe OIL TUBe REMOVED. To do so, will destroy your engine and you will have oil all over the inside of your car.
The instrument cluster can now be removed completely from the car. Take a picture of the back of the cluster for reference when re-assembly.
The instruments can now be removed one by one from the back of the instrument cluster. There are 3 separate gauges that will need to be removed. Before removing the instruments you will need to remove the small white lighting reheostat at from the bottom of the cluster. It is removed by removing the single Phillips head screw inside the white reheostat and pulling up on the reheostat.
Once all three of the instruments have been removed, take the gauge that gas oil pressure/temperature/fuel gauge and place in back in the dash opening where the instrument cluster goes and REATTACH the oil pressure tube to the back of thus gauge. Tighten the oil pressure tube with the 10 mm wrench. It is OK now to start the engine. The gauge will temporarily rest in the dash opening with no harm.
Take the car on a short drive and look at the end of the speedometer cable through the opening in the dash. The small cable inside the black speedometer cable housing should turn as you are driving. If the cable does not turn, you have a broken speedometer cable. If it does turn you have a broken speedometer head that will need to be repaired or replaced with a good used one.
Once you have determined where the fault likes, re-assembly us opposite dis-assembly. The large group of wires on the left side will only plug in one way. Look at the back of the instrument cluster on the left side for about 10 + or - pins and you will see the way that the wire plug can only go in one way. Make sure the oil pressure tube is tight and hook up the remainder of the wires according to your reference masking tape. Push in the instrument cluster into the dash opening about half way and then reconnect the speedometer cable to the back of the speedometer head. Once this is accomplished, push the instrument cluster completely into the dash opening. It is held in place by friction.
I hope this helps, let me know if you have any problems. REMEMBER, do not start the car with the oil tube dis-connected. Bill Whitmore