My A/C compressor used to make a lot of rattling noises whenever the clutch was energized. I thought it was due to compressor internal components, but it turned out to be worn mounting bushings. Everyone told me to simply replace the York piston compressor with a modern rotary compressor, but my A/C worked fine and I really didn't want to go throuh the trouble of converting the whole system just to fix the bracket.
With the head off and the exhaust mainfolds out of the way, I had a good opportunity to fix the bracket. The bracket is mounted to the engine block with three screws and to the compressor with four screws. In addition, there is a ground wire connecting both halves of the bracket. The bracket can be removed without disconnecting the A/C lines, but you do need skinny hands to get the screws back in when remounting it.
Be very careful in identifying the location and orientation of all the various parts when you dis-assemble it. It has lots of little spacers and parts.
Figure 1. Exploded view of compressor bracket
The upper bushings are made of a steel carrier with some kind of wear material on it. On mine, the wear material disappeared a long time ago and the steel sleeve has been bearing on the aluminum portion of the bracket causing most of the noise.
Figure 2. Location of upper bushings between steel yoke and aluminum plate
I found that 1/2" schedule 40 PVC pipe has the correct ID to fit on the steel sleeves. I turned the outside of the pipe pieces down to the right OD to fit in the aluminum plate. You dont have to remove too much material so it could be sanded down to the correct OD.
Figure 3. Both upper bushings with new PVC material installed
Figure 4. Upper bushings installed
The lower bushings are made of two steel sleeves with rubber between them. Over time, the rubber has oozed out of my bushings leaving just the steel sleeves rattling around.
Figure 5. Location of lower bushings
I found some nylon spacers the had the correct OD to fit in the aluminum bracket and I drilled out the ID to accept the inner sleeve of the old bushing.
Figure 6. Nylon spacer installed in place of lower bushing
Figure 7. Assembled compressor bracket
The A/C compressor is very quiet now and I don't think I need to convert to a rotary compressor for any reason. The York compressor seems to be about the same weight as the rotary compressor in my E28.