The screw that holds the rear wiper to the arm got rusted and stripped everything (the head and the threads). I lost the other screw and now I have nothing to get replacements with.

Anyone have the specs for the screw?

I would only have the Toyota part numbers for the screws and that arm.

Those screws are a pain. If you took the threads, might be best to get a new or used wiper arm.


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This is interesting. I guessed it was an ordinary M3 screw and was all set to make a flippant, dismissive reply, but figured I'd pull one of the screws and measure it just to be sure.

Glad I did. It's an M3.5 screw. I happen to have some M3.5 screws - reason below - so I measured one of them and found it matched the diameter of the 4Runner's wiper screw. The first photo shows a measurement of the Toyota screw; the second shows the measurement of an M3.5 screw.

As to why I have some M3.5 screws, I dabble with repairs to Honda motorcycles. In some old, 50-70cc Honda carburetors, e.g. CT70, there are several places with M3 screws. Carburetor aluminum is particularly soft, and these strip out quite easily. Now, one could tap the holes out to M4, but M3.5 works without drilling: the tap size, in aluminum, for M3.5x0.6 is 2.9mm. (3.1 for steel).

https://littlemachineshop.com/images...drillsizes.pdf

A more elegant solution, I believe. However, on those carburetors the screws are not in a recessed slot, as on 4Runner wiper arm, so the diameter of the screw's head, 0.270", doesn't matter. The diameter of the head on the the Toyota screws is 0.228".

I doubt you'll be able to find M3.5 screws in stores.

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I wasn't able to find them. I managed to keep one of the two screws in decent shape, but the head of the other one got pretty trashed when I replaced the wiper. I cut a new slot into it using a Dremel so I could salvage it and screw it in with a flat head.

It looks like complete trash, but then again, so does a lot of my rig so I guess it's fine for now.

Toyota sales the replacement screws? They are JIS heads. They also sale replacement arms if you can't find decent used ones. Around my area. Almost all junkyard ones are rusted out junk...



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Here is a 1998 sr5 parts diagram

1998 TOYOTA 4RUNNER SR5-V6(-0008),SR5(0008-) 3400CC EFI, AUTOMATIC 4-SPEED REAR WIPER

Screws are still available. Lots of used arms out there if you want to go that route as well.


SCREW, WINDSHIELD WASHER.
Part Number: 9009900925
Supersession(s): 9009900921; 90099-00925
MSRP $1.12



Back Glass Wiper Arm (Rear)
Part Number: 8524135020
new msrp $56.49

new blade
part number : Back Glass Wiper Blade (Rear)
Part Number: 8524235010
MSRP: $ 16.09


Slider SUB - Assembly, Arm. Wiper Arm Slider.
Part Number: 8524735010
Supersession(s): 85247-35010
MSRP $15.66

Before I lost the original screw I found one in a rural hardware store that worked, but the screw was made from really cheap metal and rusted within a few months. Apart from that locally owned hardware store none of them have it.

I really hate Toyota for using that, it would of been so easy to make a small adjustment in CAD and use a different size screw, but they had to make it a half size. Since the threads are already screwed up, can I enlarge it to an M4 and thread tap it?

I would do this: visit this company

Just a moment...

and purchase 2 socket button head stainless M3.5 screws in of length 10.(That's the only head style they sell in M3.5)

Also purchase 2 nuts. In stainless.

The screws are longer than what was already there, but the extra length is so you can put a nut - use some Loctite - on the back side.

As I see it, the problem with going to a larger size is that these screws sit in a little trench. The trench won't accept much bigger than what was already installed, which I measured at 0.228".

The M3.5 screws I use for carburetor repairs scrape the trench side as they go in. But they do go in. I'd send you two of them, but they're the same length as Toyota's screws so they won't do much good in a fully stripped hole.

Since these screws I suggest are "socket button", ie Allen key, you can grind down the outside just a little bit if needed. And since they're stainless, no rustable surfaces after grinding.

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This would be a great option for the rust belt rigs..

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Thanks for the info. Replacing the rear wiper arm and stopper is another item on my maintenance list. Looks like Amayama has the wiper for $40ish shipped.

This is the Toyota p/n for the screws: 90099-00925

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