Freeing Up A Stuck Piston PDF Print E-mail
Written by BMWVMCA NEWS   
Tuesday, 05 August 2008

Freeing Up A Stuck Piston

Photo at right shows how I freed up a piston frozen in the bore of an R26.

Materials you’ll need are a 3/4” thick steel bar at least 3” wide and 6” long,  two sections equal length steel tubing with an 11 mm inside diameter, a large socket wrench or collar that will fit over the crown of the piston. I prefer to use a socket, because I can easily add pieces to it.

Drill two 11 mm holes in the steel bar the same distance apart as any two opposing threaded holes in the cylinder.

Insert two of the bolts that hold the rocker shaft blocks to the head. Here is where you use the two sections of steel tubing.

It helps to soak the piston with penetrating oil before proceeding. Even used engine oil would be better than trying this dry.

Remove the four cylinder base nuts.

Assemble your home made tool as shown in the photo below. As you tighten the two bolts, pressure will be applied to the crown of the piston.

Draw the bolts down. If the piston moves, continue applying pressure until either the bolts are drawn all the way or the steel bar is riding on top of the cylinder. Either way, add spacers of your own invention between the top of the socket and the bar. Tighten the bolts and continue pushing the piston down, which will also draw the cylinder up.

If the piston is frozen so tight that you cannot move it with your special tool, apply heat with an acetylene torch. Heat it enough so that a few drops of water flung from your finger will boil away quickly on the surface of the cylinder. Add a little engine oil and try again.


Last Updated ( Monday, 08 June 2009 )
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