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Paul Workman · 12-07-2018

As I study the photo of the input shaft to the extent the photo allows, there was GALLING occurring in 3 distinct bands along the shaft. Why not along the entire contact length between the bearing and the input shaft??

You don't get galling between steel and bronze. There has to be a third element (steel) contaminant in the mix. And, when you look carefully, is that a bit of the grease on the end of the input shaft? Note that it no longer looks to be viscus, and it appears to be impregnated with metal filings.

I'm intrigued...

Tell ya what: Not being able to inspect the clutch components directly, a real forensic analysis is difficult. That said, and this is just a SWAG mind you, but something else was going on with that installation - i.e., the REAL reason CONTRIBUTING to the demise.

Again, I'm only seeing the pictures. I could be wrong, but there appears to be waaay too much metal filings contaminating that bearing, evident in the "grease" residue. So, I'll toss this in for your consideration, this possible hypothesis:

The grease became saturated with the normal clutch disc (dust) material, true. But, far more important is the metal filings. The combination of the two combined with the grease to form a stiff material, forming a barrier scattered randomly along the input shaft. The metal filings became dammed up and HEAT soon followed.

The bronze bushing then became impregnated with the metal filings that were clumping up along the shaft. That led to isolating the lubricity of the bronze from the shaft, and RED HOT HEAT (also very evident) ensued to the point of initiating the (steel on steel) galling evident from the pictures.

Replacing all the damaged parts sets up a "do over". And, if in fact there IS evidence of metal filings, the cause of that evidence may too have been eliminated. But, I'd really want to run that filing contamination to ground - assuming there ARE significant amounts of such contamination remaining to be found. Unless the cause of the metal filings is identified and corrected, the stage is set for a sequel of the first act.

That's my hypothesis - and worth the price of free internet advice, no doubt. I just don't buy the theory that the grease, because it was used, caused the galling. It may have been a contributing factor, but were there no metal filings, would the galling have taken place anyway?? I doubt it.

12-07-2018	#6
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,466	Re: Improper Pilot Bushing Installation As I study the photo of the input shaft to the extent the photo allows, there was GALLING occurring in 3 distinct bands along the shaft. Why not along the entire contact length between the bearing and the input shaft?? You don't get galling between steel and bronze. There has to be a third element (steel) contaminant in the mix. And, when you look carefully, is that a bit of the grease on the end of the input shaft? Note that it no longer looks to be viscus, and it appears to be impregnated with metal filings. I'm intrigued... Tell ya what: Not being able to inspect the clutch components directly, a real forensic analysis is difficult. That said, and this is just a SWAG mind you, but something else was going on with that installation - i.e., the REAL reason CONTRIBUTING to the demise. Again, I'm only seeing the pictures. I could be wrong, but there appears to be waaay too much metal filings contaminating that bearing, evident in the "grease" residue. So, I'll toss this in for your consideration, this possible hypothesis: The grease became saturated with the normal clutch disc (dust) material, true. But, far more important is the metal filings. The combination of the two combined with the grease to form a stiff material, forming a barrier scattered randomly along the input shaft. The metal filings became dammed up and HEAT soon followed. The bronze bushing then became impregnated with the metal filings that were clumping up along the shaft. That led to isolating the lubricity of the bronze from the shaft, and RED HOT HEAT (also very evident) ensued to the point of initiating the (steel on steel) galling evident from the pictures. Replacing all the damaged parts sets up a "do over". And, if in fact there IS evidence of metal filings, the cause of that evidence may too have been eliminated. But, I'd really want to run that filing contamination to ground - assuming there ARE significant amounts of such contamination remaining to be found. Unless the cause of the metal filings is identified and corrected, the stage is set for a sequel of the first act. That's my hypothesis - and worth the price of free internet advice, no doubt. I just don't buy the theory that the grease, because it was used, caused the galling. It may have been a contributing factor, but were there no metal filings, would the galling have taken place anyway?? I doubt it.