100_0068
Disassembling the insulation and outer brush seal.
100_0069
Note the washers for shimming the outer brush height. Also the rivets which hold the 1/8" Al contact plate for the inner brush, which must be removed.
100_0071
Apparently, the inner brush was never installed. It should go on this rim.
100_0073
Drilling out the brush plate rivets. We chose to leave the large insulation panels in place, and drill through where necessary. Note the vacuum to catch chips.
100_0074
Ollie cleaning up.
100_0091
The angle brackets which support the brush plate interfere slightly with removal of the faceplate. The height of these brackets must be adjusted precisely to match the inner brush (although previously, with no brush, this was not important). Removing the brackets would require us to replace and adjust them during the crane visit, very time consuming. So we created some clearance.
100_0092
It is now possible to replace the faceplate with the brackets, insulation, etc. all in place.
100_0093
Not quite done. Note the grease fittings at 90 degree spacing around the faceplate edge. The new interface plate has these on the drawing, but they were not drilled.
100_0237
After the first crane lift, when we discovered the plenum ring rides too high on the brush seal, Dave Pernic took extensive measurements of the runout.
100_0238
We decided that a combination of lowering the brush seal and shimming the plenum ring would work best.
100_0239
Insulation was cut out and new screws installed to compress the brush seal level.
100_0255
Results of the runout measurements show that the 20 mount points for the plenum ring on the steel interface plate are quite uneven.
100_0256
They range from +.030" high to .150" low compared to the design height of 76mm above the theta bearing.
100_0317
After the second lift, we discovered a third problem: dishing and warpage of the plenum ring itself causes its outer edge to make uneven contact with the brush seal and metal rim. Dave ground off the outer edge to ensure brush contact...
100_0318
...and shimmed an average of .100" to take out the effect of the dish and reduce the unevenness.
100_0319