One of the common areas of failure in the BW 310 converter is the wear at the center of the piston as it contacts the turbine hub. This wear is due to the damper assembly splines being offset from the piston center causing the piston to contact the turbine hub and wear prematurely. Many rebuilders are repairing, or replacing the piston, but if the damper assembly is not centered with the piston it will wear out prematurely also. I have found that even though the damper assembly is centered with a turbine hub before riveting it to the piston, it will not always stay centered with the piston after the riveting process is complete. The best way I have found to keep the damper assembly centered, is to center the damper assembly on the piston with a turbine hub, then temporarily bolt it together with two 1/4 inch bolts across from each other and tack weld it at the bolts (see photo). Then rivet the remaining holes in the assembly leaving the bolts in place to keep the tack weld from breaking. After the other rivets are installed remove the bolts & replace with rivets. (Some rivets may have to be tapped in due to the holes being slightly off center) This procedure will help keep the damper assembly centered to the piston preventing piston bore wear. The piston is now ready to be balanced.
Rob Hans, Norfolk Transmission
– Found in July 2010 Newsletter