Bypass valve bushing replacement

I did not replace the bypass valve bushings but removed the shaft. Removed the disc from the shaft and had the shaft ends plasma coated and then precision ground to the original OD. My bushings had not worn but the shaft had worn considerably resulting in a rattling valve.
The cost to plasma coat and grind was around $200. The labor was not bad to disassemble and reassemble the valve. Only recently finished so I cannot comment on the life of the rebuilt valve assembly.
The Capristo unit appears far superior to the OEM product. From what I understand Capristo uses SIC bearings. If the shaft is also a better quality material I would expect considerably longer life.
Good Luck!

 

There was a thread where someone used a roll pin to act as a stop against the lever. I just tig welded a bit of stainless on the corner of the lever on mine to accomplish the same and it's working perfectly.

 

I would try increasing the preload tension on the valve first. Remove the valve, and adjust the diaphragm preload tension. Probably two or three full turns is enough, and give that a try. Worked for me. I went ahead and got the Capristo anyway though... Careful, too much tension can keep it from opening.

BTW, JH355 on this forum has experimented with fixing the bushing. From the sample he showed me, it was the end opposite of the diaphragm that has the bushing, it is basically the metal end cap. He cut it off, CNC'd a new one of slightly tighter dimensions, and tack welded it back on. Said it requires a bit of trial and error to get the dimensions just right, as you cannot make the new dimensions too tight, as everything tightens up from heat/expansion, and can cause the valve to stick open, or closed.

The Capristo solves the problem by putting each end of the spindle/rod under spring tension. This allows a slightly more loose clearance, yet no chance of the valve rattling.