Join Date: Dec 2006
Location: Wilmore, Kentucky
Feedback Score: 0 reviews
Re: AC shim hints
Additional thoughts about the shims.
One of the questions I had before I took the shim out was, ďWhy is it there to start with if it keeps the compressor from kicking in?Ē Once I got it apart I could see the genius of the system. When the clutch is new everything works great because when the compressor and the clutch are assembled the air gap is what it should be. As the clutch and its mating surfaces wear, the air gap between the two surfaces increases to the point where it is hard for the magnetic forces to overcome the air gap and engage the clutch and it becomes intermittent. I think one reason we see the problem first appear when the rpms are low is that the alternator is putting out a little less voltage. When the rpms pick up the voltage increases a little, the magnetic force increases and the clutch kicks in. This works until the mating surfaces get worn so much that even the higher voltage wonít increase the magnetic field enough to engage the clutch. At this point Ford could have sold us all new clutches but it looks to me like it was designed that by simply removing a spacer (shim) we extend the life of the clutch. Once I did it I bet it isnít a 15 minute job. From what I have read when the clutches are new there is probably more than one shim installed. As the clutch wears you take them out one at a time until they are all gone. Once that happens and the air gap increases to the point that the clutch is again intermittent you are looking at a new clutch because there is no more adjustment. Some of the real mechanics on this site may disagree with my analysis and if they do I will defer to their experience.
I hope this helps someone.
All I need to be a better mechanic is a bigger hammer!
2000 F-250, PSD, 4X4,Auto,
Pyro,Boost,Trans Gauges A pillar isspro guages,CC, short bed, Extang Tool Box Tonneau Cover
upgraded headlight harness, locking fuel cap,
Dual car seats for twin granddaughters
Currenty 228,000+ miles