Front Wiper Arms - Should they have splines?

[andyak]

So, while loaned out, driver's wiper stopped moving. My friend tightened the nut and it started working again, for a while.  
I checked and the motor is working - shaft is turning inside the arm.
I pulled the arm, set the position and tightened it down....things seem OK, but I'm wondering.....should the taper on the inside of the arm have splines in it?? Or does it just sort of look like it has messed up splines because it was tightened down, but then stripped by the motor shaft turning back and forth while the arm didn't move?
Should the splines on the motor shaft just cut their own grooves as you tighten the nut down??

 

This is a 2016 Edge Titanium.

Edited December 21, 2021 by andyak

[CARR142]

Should the splines on the motor shaft just cut their own grooves as you tighten the nut down??  NO.

[enigma-2]

In my experience, all arms have groves. Needed to drive them through snow and wind.

A new OEM arm will run around $41.25.

Right side is P/N FT4Z17526B, left side P/N is FT4Z17527A. 

[omar302]

On my 2016 Edge Sport, the motor shaft and wiper arm both have splines. I had removed the wiper arm a few times and can confirm it.

[andyak]

3 hours ago, enigma-2 said:

In my experience, all arms have groves. Needed to drive them through snow and wind.

A new OEM arm will run around $41.25.

Right side is P/N FT4Z17526B, left side P/N is FT4Z17527A. 

Mine as well, but also they were straight openings and not tapered.

I may see if anyone has one in stock and inspect a new one.

[andyak]

31 minutes ago, omar302 said:

On my 2016 Edge Sport, the motor shaft and wiper arm both have splines. I had removed the wiper arm a few times and can confirm it.

Mine has splines on the arm side, but they look like they might have been made by tightening down the nut.  If it had never spun, they would look pretty clean, I think.

 

[omar302]

3 hours ago, andyak said:

Mine has splines on the arm side, but they look like they might have been made by tightening down the nut.  If it had never spun, they would look pretty clean, I think.

 

 

I remember the spline because when re-installing the arms I couldn't align them to the exact position 100%. When seated they would be either a tad above the mark on the windshield or below due to the engagement of the splines.