Hi everyone, I picked up a Hamilton 974 a while ago off ebay. Seller said in running order. watch would run, after a shake, albeit sluggishly. After cleaning and oiling, it will run great in certain positions, start after a couple winds, but it appears that the balance wheel and the third wheel are coming into contact in pendant right and pendant down position. I am wondering how to check end / side shake and how to correct it. Also, would it be possible someone put the wrong size balance wheel in this watch?

Gary,
You might have already looked at these possibilities but...
Check to see that the balance bridge is screwed down tightly. Check to make sure the balance jewels are screwed down tight and properly seated. See if a previous watchmaker bent the balance bridge. Some watchmakers do that so they don't have to adjust pivot length when they staff a watch.
Also, check to see if someone has the balance screws or mean time screws too far out.
I don't have a 974 but perhaps someone can post what the pivot thickness and length is supposed to be.
Your endshake seems fine if you are having no problem in dial up and dial down. Side shake can be checked by removing the balance bridge and putting the bottom balance pivot in the lower jewel hole. You want to see around 5 degrees.

Gary,
You might also try this. Let the power down on the mainspring and the remove the pallet. Now reinstall the balance and balance bridge and give the movement a flick of the wrist to get the balance in motion. Watch the balance spinning in all positions and see what it does. The balance should not be sluggish in any positions and certainly not hitting anything. Notice if the balance is wobbling at all. After you do this, let the balance come to rest by itself, and look at the roller jewel. It should be in the center of the banking pins.
Let us know what you find.
Good Luck,
Brian C.

Hi Scott and Brian, first of all thanks for the replies. Here is what I've found so far. The lower balance jewel seems a likely problem, as one screw has the head broken off and the other will turn, but not thread out. The balance bridge appears normal and screws down tight. Brian, I did as you advised and the balance spins freely in all positions and comes to rest with the roller centered, however the inner banking pin seems very slightly bent to the center wheel. Also there does seem to be some up and down looseness in the balance wheel.