The picture will be explained shortly.
So, I just took the Town Car in for an inspection and I need a new upper ball joint. I forgot to ask about a pickle fork at Autozone, so I did a quick search on how to remove a ball joint without one. I’ve done it before by threading the nut down to the end of the bolt and beating on it with a hammer, but I thought there might be a better way. Turns out there is!
I found this method of hitting both sides of the taper joint with two hammers at the same time. They described the action thusly:
hammer either side of the taper at a slight angle. This squeezes the bottom of the housing that the taper fits into, and opens up the top.
I thought that was an interesting description, but what does that actually look like?
Being an engineer and having access to finite element analysis software, I did a quick study of it.
I made a very crude approximation of the suspension bit with the tapered hole in it. Then I applied an arbitrary force to a few nodes where I imagine the hammers would contact. About 1000 lbs per side. What I was looking for was the deflected shape, not the stresses, so the force wasn’t important.
The results clearly show that the bottom hole is squeezed and the top doesn’t deflect much.
It looks like I picked realistic forces after all, because the points where I applied the load are just about at the yield point for steel. As you might experience, when you hit a heavy piece of steel with a hammer, there is a slight flat spot or divot. The metal yielded. You can also see that the stresses drop way off away from the hammer blow. We are no where near breaking the part with this load.
I’ll tell you how easy the ball joints come out tomorrow!