What do you mean by "not hitting at the top of the arch?"

If the blade is making full contact on both sides of the stroke, but it is not making contact at the top of the swing, the blade may be too long and the tip may be getting lifted by the mounding around the window.

I haven't measured, but I thought I had an 11-inch blade because the 13-in her as too long on my '82 245.

Rear wiper blades lead a tough life - they are bombarded by dirt and gunk and never get the nice wash that front blades get.

Have you tried cleaning all the joints with a brush and soapy water, lubricating all the joints (including the joint at the beginning of the wiper arm) and flexing the joints until they move freely?

This has worked for me.

Do you mean it is not going high enough... Closer to the top edge of the glass.
Just go for a longer blade.

I have used different lengths on the back of my 245 over time, usually left over from one side, but still good when I change front wipers on one of my various vehicles (940, 740, 245 ....Ranger pickup).

At the moment I have an 18" blade on the back... just clears the rubber at the edge.
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"Do you think that's air you're breathing now'? (The Matrix 1999) '94 940T (463K+), 92 245 (300K+), 90 740 (148k)