Last time it was my windshield washer sprayers, which I found out were easy to remove, making it far easier to align them precisely.
This time I'm looking to replace my wiper arms. I found a pair from a seller in Thailand on eBay. I was worried they were said to fit an LN40 Pickup, rather than Hilux, which most parts sellers designate, but my local dealership said LN40 is the chassis designation for those older models.

Anyway, my question is what can cause and how to fix a problem with a wiper blade suddenly not flipping as it changes direction up or down? It's suddenly started happening on my driver side wiper, and it causes it to chatter severely. Spraying wiper fluid on the windshield momentarily alleviates it, but once that is wiped away, it goes back to chattering.

Coincidentally, that is also the one arm where the plastic cover that goes over the fixing nut, broke off at one end, which exposes the part of the arm that allows it to pivot away from the windshield when cleaning the windshield by hand. Needless to say, that pivot has accumulated a bit of rust since the cover broke off at that end.

The blade assembly though is the original Denso brand I always buy as replacements, and it's not old or rusty. I have however for months been regularly hand washing my hood and roof, as I just got them repainted. Part of that ritual is wiping down the windshield with hot tap water with a foam sponge, and wiping it dry with a big cellulose sponge I got at ACE Hardware.

The cellulose sponge has antimicrobial properties that when it was new, left a bit of film in the bucket when wringing it out, but after using it numerous times, It seems there's no such residue anymore. This is also as I said, something that just started happening, so I'm doubting the antimicrobial agent has anything to do with it. It's not likely tree sap either, as it doesn't look or feel sticky when I wipe the windshield down regularly by hand.

BTW, the wiper arms I ordered from Thailand won't be here until Jan 14, so there's certainly no rush to figuring out this dilemma. The only thing I thought of trying meanwhile is using the foam glass cleaner I buy (Sprayway), and if that doesn't work, I do have extra brand new Denso wiper blades I can put on. I suppose I could also try lubing the rusty pivot on the driver side arm, in case it's causing the blade on that side to move more stiff than normal.

So, does anyone know what could be causing this, or how to remedy the situation?

Thanks in advance for any comments or help, and hope you're all getting through COVID OK.

 

IS this happening only when dry or in the rain too? You might want to try bending the blade with your hand so it is angled more. Pics would help too

 

No it definitely happens in light rain too, but only after the washer fluid is wiped away (but still raining). That said, I can minimize it if I let the rain drops accumulate, then flick them on for one wipe them turn them off. Like I said, it's only the driver side wiper, and it used to not do this.

I'm hoping the new wiper arms will resolve it.

 

Swap the two blades & see what happens...just the blades to start with...🤔

 

Yeah I was thinking of doing that. All I've done so far is clean the windshield good with glass cleaner to see if that antimicrobial cellulose sponge was leaving any residue behind. I'll be driving it later today, but looks like it's going to be dry and sunny here, so can't test the wipers yet. Right now I'm more concerned about a glass cut I got on my right hand after putting some broken glass in the recycling dumpster I was cleaning up. It's been a week since the injury happened, and I'm starting to think it might have a touch of staph infection. Gotta go see the doc Mon morn.