I finally took my '70 Maverick for its first ride around the neighborhood and i noticed that when i would let off the throttle, i would get a slight thud from the rear center of the car. My initial thought was the u joint. Does that sound about right and how difficult will it be to replace/rebuild it? I know i ask alot of greenhorn questions on the forums. I'm new to working this extensively on a car. And something this old.
I have experienced that exact thing with a bad u joint. They are not too difficult to replace, there are 2 u bolts that attach it to the differential yoke. There are typically 2 c clips that hold it in place on the drive shaft. Make sure to chock the wheels first because as soon as you disconnect the drive shaft from the yoke there is nothing holding the car in park.
Another symptom of bad u-joints would be a shake that appears at around 45 mph. If it is doing that, they are really bad. Had one car do that, and when removed, everything inside the joint was busted up into little pieces. Another thing to watch is not to overtighten the straps on the cups. You want them snug, but too much can distort them. If you buy them with a grease fitting, you will need to grease them up after installing. Some are sold sealed and pre-greased. I prefer being able to grease them a bit later.
before you pull the yoke out of the transmission tail shaft...see how much side to side and up and down movement there is. if very much you may need to replace the tail shaft bushing and seal.
I like to mark the driveshaft and yokes so it gets put back on in the same place it came from. Might be overkill but I figure if I don't have a problem with being out of balance, why go looking for some. Many auto parts stores have the u-joint c-clamp type press in their loaner tool section. Makes doing joint easy.
