Removing piston wrist pins

[ssevy]

The manual implies these should slip out easily, but mine have been in there for 22 years and 43,000 miles, so they did not want to come out. After having no success at getting them to budge, I did what I always do, and began looking through my assorted junk bins to see if anything sparked my imagination. Fortunately, something did, and it worked so well that I thought I would share it for any others who find themselves in my predicament.

You'll need a 1/4" concrete anchor, a long screw with the matching threads for the anchor, a bronze bushing that the anchor will slide into snugly and a nut.

Here they are


You'll also need a crescent wrench (SAE or metric  ) and a hammer. I always use a deadblow myself.

Step by step:

1- Turn the crank to get piston #2 up high and clear. Stuff some rags tightly enough around the piston to wedge it into place and keep it from hitting anything metal. Be sure to leave each end of the wrist pin exposed. Lay additional cloths over the other two pistons to keep the circlips from falling into the crankcase.

2- Remove both circlips, insert a socket of the correct size into the wrist pin channel and tap the wrist pin out carefully. Once it clears the con rod, you can gently lift the whole assembly out and bag it.

3- Turn the crank to get piston #3 up high and clear. Again, stuff your rags to stabilize the piston, cover the remaining area and remove the inner circlip.

4- Slip the bronze bushing around the section of the anchor that is not threaded, spin the nut on the long screw, then insert the screw through the bronze bushing end of the anchor and then thread it into the other end until it sticks out a bit. Now insert the end into the wrist pin as far as you can.

5- Using a wrench, tighten the nut down until the anchor is tightly wedged into place.

6- Close the crescent wrench up until it just slides over the thickness of the screw threads, seat it against the screw head tightly, and then use your hammer to tap on the wrench close to the screw shaft to gently pull the wrist pin out.

7- Repeat for piston #1.

Here is the tool inserted in place


Here is the crescent wrench in place


Here is the piston on the bench before removing the tool


In case you are wondering, the bronze bushing holds the wedge assembly at the opposite end of the anchor in place, which provides the resistance necessary for the other end to grab as tightly as possible. These anchors are designed to be fully inserted in pre-drilled holes in concrete, and they really apply strong outward pressure when used correctly.

All the photos are extra large if you click on them for more detail.