Windshield Wiper Issues

Ok, so on my '70, I have the single wiper motor setup, mounted externally with a nifty chrome cover, and the transmission to the wipers themselves, mounted internally to the windshield frame.

Put the drivers Side Wiper on, everything works fine. Put the Passenger side wiper on, in the shop, fire it up, and everything works fine, it will basically just sit there and run fine, for what seems like forever (let me call it ten minutes, I've never actually clocked how long I've sat there watching it)

Get it out of the shop, it starts raining, turn the windshield wipers on?

Within 30 seconds, every time, the passenger side arm bangs all the way down and jams itself against the cowl, requiring me to pull over, and pull the passenger side wiper arm off, and then the drivers side will work just fine.

I've pulled all the plugs out of the windshield frame, and observed the wiper transmission in action, and nothing *appears* to be amiss, bent, or broken.

So I've got questions, as I'd rather like to have two working wipers.

1) My wipers, I assume, should park towards the passenger side, and move in parallel, right to left, when running. (I ask this, because I've actually had the passenger one do the cowl jam thing, and when I popped the arm off, and reset it, my wipers both parked towards the center of the dash, and ran counter to each other)
2) Is there anything I should really be looking at to see why this is happening?
3) Is there any possibility of using a later wiper arm, or one from another vehicle, to be able to get my hands on something other than the trico style wipers?

 

I have to ask is this a replacement windshield frame . and in order for the wiper pivots to change directions , I would think the passenger side linkage has jumped from bottom to top at passenger side pivot

 

I have absolutely no clue if it's an OEM frame or not, it's what was on the Jeep when I bought it. Far as I know it's an original.

 

It's been a while since I've had this apart ...

The motor rotates continuously and the wipers are connected to an arm on the motor that moves them back and forth, like the connecting rod on a steam locomotive. The only way that the wiper can go into the cowl is if one end of the travel is very close to going over-center and oscillating on the opposite side of the circle. That is, the wiper moves back and forth in an arc that is less than one half turn of a complete circle. The wiper should never go over-center if it is operating in the middle of the half-circle arc. If it's near the edge of the half-circle, it could be nudged over into the other half-circle arc.

Kinda wordy but I hope that's clear.

IIRC, inside the windshield there is a long rod between the two short arms that turn the wipers. There is another rod that connects the arm on the motor to the long arm. Pretty sure if you take the motor off, both of the short arms should be pointing straight down when the wipers are pointing straight up. The motor should park at a location where the arm on the motor is horizontal to the left, moving the wipers to the far right (I think).

It sounds to me like you have the pivots for the wipers inverted, so the long arm is above the pivots? Or way out of phase with the motor? The only thing I can imagine that would make the wipers move in opposite directions is if you have one arm pointing up and the other pointing down.

As I recall, there is a keyway on the motor and keyways on the windshield frame, so that everything is in phase when it's installed? Dang - I should have taken pictures.

 

1. The wipers should move parallel to each other and in tandem. They should both park towards the passenger side
2. Why wipers don't fail in the shop, but do outside??? If the driver's side works fine--I would think it has to be linkage, if the passenger wiper arm is installed to match the position and travel of the left, and something is not loose.
3. ----

 

Honestly, this helps a bunch tim, thanks. It at least gives me a better idea of what i *should* be seeing when I'm looking. The passenger side pivot is the only one I've actually taken out to have a look, and yes, they're keyed in the windshield frame.

I guess I'll take some time tomorrow and take everythign apart and go over everything, I haven't done that yet.

 

Right, that's the part thats making me insane. Running it on a dry windshield, in the garage, which *should* be providing more resistance than a wet windshield, it operates as expected.

 

Well, wet might make it fail and go over-center. The drag of a dry windshield could push all the slack toward the center of the arc. With lubrication, the arm might go a little further and go slightly past the crest of the hill, figuratively speaking. Try it with soapy water on the windshield and see if you can make it fail.

 

the only reason I asked it it was aftermarket . was I had real problems with the passenger wiper pivot . as tim noted , the wiper arc is less than half . any more and the linkage will jump over , both wipers pivot on the bottom . I wound up cutting 1/4" off linkage to passenger side .and welding it back together never a problem since . aftermarket frames some are ok some not . now if's it's still a factory frame . did the passenger wiper pivot twist in frame

 

Can't find any sort of issue with the linkage, the pivots are still "tight" and keyed properly in the windshield frame, but I do notice that the wiper blades are hitting the windshield gasket. Which leads me to my next question. I'm getting conflicting information from the various vendors out there. Should the wiper blade length on a '70 be 9", 10", or 11" ? Because different vendors are showing the 11" fitting from '74-'86, the 10" fitting from '68-'74, and the 9" from '55-'75.......

 

don't know if this helps but my 71 has 11" blades

 

Re Ron's previous comment, it might be helpful to measure the distance between the wiper pivots and compare that to an OEM windshield. I know mine is original, and I can measure sometime, maybe tomorrow morning in the light.

 

My windshield has the pivots set at basically 26" apart, center on center

 

ok so why not try this . with wiper blades still installed . disconnect the link from wiper motor link to drivers side pivot . also disconnect the long link on passenger side , position both wipers 90* on windshield . and see if you can . reattach passenger side link . without moving wiper arm pivots . both pivots must be on bottom

 

That's what I did this morning. And also noticed that being banged over into the cowl has bent/broken both the arm and blade, hence my question about the blade length I actually should have. The wiper arm, there's no ambiguity about, the blade, there seems to be.

 

My 71 has the original windshield, I just measured and yes it is 26" center to center