piston pin

Does anyone know of a tool that makes it easier to remove the gudgeon pin ? I know that heating the piston helps but I would still have to hammer it out, which I think could cause damage. Thanks!

RE: piston pin

Look at all the small engine manuals you can find and in one of them there has to be a diagram of a puller you can improvise using a long bolt that goes thru the gudgeon pin with a washer of a diameter slightly smaller than the diameter of the gudgeon pin.

You place the washer over one end of the gudgeon pin and put the bolt head on it. The bolt head diameter must be smaller than the gudgeon's outside diameter. Now on the other side of the piston where the threaded end of the bolt comes out you place your deep socket whose inside diameter is larger than the gudgeon's outside diameter. The bolt must be long enough to pass through both the piston and socket.

With the threads sticking out of the socket and the socket against the piston, you put a washer over the end of the bolt and a nut on the bolt and carefully screw it together. Make sure everything lines up so the bolt won't scratch the gudgeon pin hole on one side and slowly tighten the nut against the washer on the other.

As you tighten the nut it pulls the bolt head against the gudgeon and pushes it out into the socket.

The hard part is getting the bolt the correct length with the right size head. I've used a 1/4" round head screw and ground down the head diameter in some cases.

Works every time for me..

RE: piston pin

Thanks Jim. So, to make sure I got this right, you put a washer on one end of the pin, put the bolt through the pin so the head rests on the washer, a socket on the other end of the bolt, then a washer and finally a nut ?

RE: piston pin

Absolutely right!

Be absolutely sure that the bolt head is smaller than the hole thru the piston. When you tighten the nut, it will pull the bolt thru and you don't want it to scrape the wall of the piston's hole.

To install the gudgeon, you do the same setup again except without the socket. On the end of the bolt that came thru the socket you put the washer on first and then the nut. Line up everything carefully again and tighten the nut til the gudgeon just passes the the snap ring groove.

That's it!

Works for me all the time. Just do it all carefully!


RE: piston pin

Reeperette /

You could also try a small wooden mallet, like from those old kids toolkits, and a cut off section of dowel rod.


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