Posted: Sun Feb 29, 2004 11:12 am
Bill, I highly encourage you to play with them. They are a marvel of design. Bet you will spend two days just getting the path of fluid flow right in your mind. That top plug with the O-ring around it is a critical valve. On the up-stroke...the fluid that has bypassed the piston valving stack...and gone to the top of the piston...must by-pass (at a pre-designed rate) the bronze sleeve at the top...into the gallery surround the bronze sleeve...and exit the holes in the top flange below the o-ring...back into the main body of the strut....outside of the central tube. That is the resoivoir. Wherin...they are then drawn back into the shock tube through that little bitty metering hole in the bottoming plate.
The rate that the fluid drains from the top side of the piston back to the resoivoir...must not exceed the rate at which replenishment fluid from the surrounding resoivoir...can be drawn back into the lower side of the piston...or there will be nothing to compress on the next down stroke. The piston itself has finely machine chrome piston rings riding in a polished steel bore. I have not been able to bring myself to throw them away.
One thing to note...is that the early supers all had the same basic pistons and rings inside...on a different rod. But..had the same strut tube internally. So...you can rob shims and valve and piston heads from supers to rebuild 411-412. But, there cannot be a single rust pit internal. They must be squeeky clean. You must also keep the correct stack of valving shims (measure them)...check the # of notches. It is almost impossible to get each strut balanced from side to side. They were beutiful when new...but just a little under-damped.
The correct height for th fluidcan usually be noted from the stain on the inside of the strut body andon the strut tube. But...its difficult. This is with the strut unit pumpedup full...then at rest....assembled. At that rate, the fluid height surrounding the cartridge is alittle less than half the tube height. Ray
The rate that the fluid drains from the top side of the piston back to the resoivoir...must not exceed the rate at which replenishment fluid from the surrounding resoivoir...can be drawn back into the lower side of the piston...or there will be nothing to compress on the next down stroke. The piston itself has finely machine chrome piston rings riding in a polished steel bore. I have not been able to bring myself to throw them away.
One thing to note...is that the early supers all had the same basic pistons and rings inside...on a different rod. But..had the same strut tube internally. So...you can rob shims and valve and piston heads from supers to rebuild 411-412. But, there cannot be a single rust pit internal. They must be squeeky clean. You must also keep the correct stack of valving shims (measure them)...check the # of notches. It is almost impossible to get each strut balanced from side to side. They were beutiful when new...but just a little under-damped.
The correct height for th fluidcan usually be noted from the stain on the inside of the strut body andon the strut tube. But...its difficult. This is with the strut unit pumpedup full...then at rest....assembled. At that rate, the fluid height surrounding the cartridge is alittle less than half the tube height. Ray
