RCK54 3 blade MMM, middle, aluminum blade support corroded?

[tshep]

Casting that holds lower seal/bearing/seal combo (upper is gear).
The edge, that happens to guide a O-ring so grease can travel through, corroded away, for 3/8s or so, right where it should support the grease O-ring.
I 'rebuilt' it with JB Weld, but wondering if it is a 20 year old missed, bad casting vs corroded.
Example Kubota #K5371-34113 ASSY HOLDER, PUL 2nd pic
Some edges (similar exposure) look great
I'm in central VA, mower could be from anywhere, fairly close.
(My google-fu finds grass does not eat aluminum.)

 

[TMGT]

Do you have a picture of the damage? I've seen aluminum spindles have bad corrosion in areas, most likely from the moisture from decomposing grass, also when decomposing the grass can change PH which could cause problems.

I doubt if the casting was what bad it would have made it through qc.

 

[tshep]

Hey - we keep crossing!
Based on your report (I have limited experience), I'll go with corrosion, as it was my my first guess, now confirmed. The short sides are lateral to the mower, and thus 'stop' the wind and grass, as the long sides are cleared by the wind.
I was in a rush get finished before vaca., and the damage is 'repaired/recast' in JBW.
I will be sure to paint the bare Al.

 

[TMGT]

I wouldn't paint the aluminum, usually just traps more moisture, I've found the best prevention is washing thoroughly and running the deck after to help dry it.

The dryer the grass when mowing the better.