QuestionQUESTION: Hello Howard,
It's me again. That temp sending to the temp gauge on the 1980 mgb fixed my cooling system. Thank again.
I got the state inspection done, and it is ready for the road again. Except - the speedometer does not work now. I don't know where to begin. I will tell you that before I put the engine and transmission back in the car, I filled the transmission with oil, thinking to save time and aggravation putting it in from under the car. Maybe that was a mistake and I should have waited, because while putting the engine while attached to the hoist, when I tilted it to get it in, oil started running out of where the speedometer cable goes into the overdrive. I managed to plug it up and not lose too much oil, and after it was in I removed the oil fill plug fot the transmission and let it drain (I guess it was overfilled due to not being at the right angle when I filled it).
Any suggestions?
ANSWER: Remove the speedo cable form the speedo and watch the cable as you move the car. if the cable rotates hold the end of the cable lightly with your fingers to be sure the cable is turning firmly. If it is the speedo itself is bad. If it is not then you need to remove the inner cable and examine the cable and ends to see that the ends are good and square. If the cable is good look at the 90deg drive on the OD to see if it is good and that the square piece of cable and the square socket on the cable side is OK. Then if all that is OK you will need to insert a small square ended piece of cable or a small flat blade screw driver and hand rotate one rear wheel while holding the other wheel to see if the drive in the OD is powering the 90deg drive firmly.
Let me know,
Howard
---------- FOLLOW-UP ----------
QUESTION: Howard,
I didn't have to do any of your recommended tests because when I removed the cable from the overdrive, the pinion gear was not there. No wonder the speedo didn't work! I got a new pinion gear - don't know what happened to the old one, it must have gotten thrown out accidentally. The dial on the speedo jumps around quite a bit especially at low speeds. I seem to remember it was always like that. It's been over 2 years since I drove it. Is that a normal thing?
Now to my next problem. Throughout all of that testing I did on the cooling system, I never had any leaks. Yesterday, after installing the speedo pinion gear I took a test drive to test the speedo, and when pulling back into the garage noticed a trail of liquid on the driveway into the garage. Antifreeze is leaking - looks like from the water pump. I had installed a new expansion radiator tank cap (aftermarket), which is rated 16 psi, not 15 psi like the old one. Could that cause leaking? Or, what else - a gasket?
AnswerSpeedo needle jumps at low speed. This is usually a kink in the inner cable.
Coolant leak, look with a small mirror at the bottom of the water pump at a hole under the shaft. (called a weep hole)while the engine is warm and there is pressure in the system. If the leak is from that hole you need a water pump, if it is from the hose or the gasket surface, you just need to correct that.
