John Deere 717A 48” Ztrak <30000 serial number

[pikewrench]

After 17 years of mowing one of the bearing on the mower head needed to be replaced, ordered the seals and bearing to do all three but found that the housings on the middle and near the discharged were badly eroded to the point that there was little material left around one mounting bolt. Found that they do not sell just the housing and that there are very few in stock, and those that have any are really proud to the point of $250+ for just one. Found a listing on eBay for one that said would fit all Ztrak 48 thru 72 inch(80-12-080R62 At EPR distribution) $263 for three heads. The mower heads look identical except the pulley is 3/8” large in diameter and the swap of the old pulleys mate up fine. The cutting blade and bolt both work on the new head and the 6 bolt pattern matches up.

 

[Richard001]

This is just another example of poor engineering. It appears that the spindle brackets are made of aluminum and are bolted to a steel deck with steel bolts.
From Here: https://www.simpletwig.com/blog/galvanic-action-corrosion-prevention/

CHOOSE SIMILAR METALS to AVOID GALVANIC ACTION ALL TOGETHER:

By simply choosing metals that avoid galvanic action there will never be an issue. Yet in today’s construction world it can be easy for a contractor to mix the wrong type of fastener with the wrong metal.

In this respect, one should understand how to read the following chart which lists all metals. SimpleTwig will then try to extract the most commonly used construction metals for a separate chart, to help ensure the prevention of Galvanic Action on our projects and for those who use this article on their projects.

Richard

 

[pikewrench]

Your chart says aluminum and carbon are OK. If this was a problem all that would be needed is a gasket to separate the two metal. The eroded metal appears on only two of the three heads, the first which has no discharge passing by had no damage. The middle and the head by the discharge chute had the erosion. Since I live out in the country I do not have a finely manicure lawn, but mow almost 14 acres and since this is an 04 model a little wear and tear is not out of the question. What surprises me is the cost of parts that seem to all originate from China. The mower head I quoted looks exactly like the original, minus the erosion and one third the price.

 

[Richard001]

Moisture accellarts the galvanic action. Yes you could put something between the spindles and the deck, but you still have the bolts going contacting the deck and the AL spindles. And as you have noticed, the area were the bolts go thru the spindles is the area that shows the worst of the corrosion.

There really is no fix for the issue on your deck. However double checking the char, it shows that carbon steel is compatible with the AL, so there maybe some hope.