Posted by Rick Denney on November 20, 2001 at 10:50:33:
In Reply to: Re: Re: Re: S linkage, sound, and a little click too posted by Doug on November 19, 2001 at 21:24:04:
A rotary valve consists of a casing with a soldered-in front cap and a force-fit rear cap, which is covered up by a screw-on cover. The rotor fits into the casing, and has a shaft on each end which is four or five millimeters in diameter. The rear shaft slips into a hole in the rear cap. That hole is called a journal bearing, or bushing. The front shaft is much longer, and fits through a hole in the front cap of the casing. The holes in both caps are shaped like a tube, and when the tube wears out, it can be squeezed down a bit with special pliers, and then honed to fit the shafts. On the front of the valve, the shaft sticks out far enough to have mounted on it the stop arm, which is the lever to which the linkage is connected. The stop arm also has a pin on it that rests up against the bumpers to control the position of the rotor.
This is a lot easier to show with pictures than with words, and hopefully you'll be able to follow along if you are looking at the valve as you read this.
If you look under the edge of the stop arm, you'll see a tiny bit of the shaft between the stop arm and the bearing that is part of the front cap of the rotor casing. That's where you apply oil with a needle oiler. You can also unscrew the rear cover, and apply oil at the interface between the rear shaft and the bearing on the rear cap. If you move the valve with that cover removed, you'll see where the shaft turns within this bearing. Put oil there. Those are the bearings of the rotor.
The rotors themselves should not drag on the inside of the casings, but should be very close. If you squirt some regular light valve oil (as opposed to the heavier rotor oil for the bearings) down the leadpipe, it will find its way to the rotors and help them seal against air leakage and also help avoid the corrosion and buildup that will require disassembly (which should be left to your repair tech).
Rick "who hopes somebody still has that useful link showing pictures of this stuff" Denney