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Wiper arm linkage assembly parts

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9 hours ago, Captain Obvious said:

Namerow,  Don't know how your music wire project is turning out, but I was at a parts store today and spied the spring that I think could be modified to replace the original clutch.

Thanks, CO.  I'll take a look in my local auto parts stores the next time I visit.  In the meantime, I made my own spring and installed the full wiper assembly back in the car yesterday afternoon.  Given the way that the spring clutch operates, I decided that it wasn't important whether the spring is made from tempered wire or not.  In fact, it seemed to me that it might work better without the tempering -- so I made my new one out of 0.065" hardware store wire.  I'm a little concerned about the durability of the tang, but only time will tell and, hey, if it breaks off, I'll just be back to 'normal'.

My new spring came out pretty darn close in ID to the original spring, so that was good.  The stack height was close, too (the OE spring is 2 coils in height).  I also took care to wind the coil it in the same direction as the OE spring.  I debated about whether the shoulder of the eccentric washer should be greased or not, but decided in the end that no grease could lead to breakage whereas grease - if incorrect - would only lead to clutch slippage (i.e. 'normal').

So, with everything back in the car, I hooked up a 12V power source the the appropriate connections and turned it loose.  All good in 'HI' and 'LO'.  Then the big test, which was to engage 'OFF' (you do this by opening the motor relay's ground circuit).

The result?

Well, I'm not really sure.  What I know is that the motor and linkage stopped, paused briefly, and then reverse-rotated to the 'PARK' location -- where everything just stopped  What I can't tell is whether the spring-clutch ever kicked in.  I tried several cycles, thinking that the new spring might need time to bed in.  No detectable change, though. 

I was running the system without the wiper blades attached (just a clothes peg mounted on each of the wiper shafts to give me a visual), so I guess that's the next step.  My new theory is that it may be necessary for the motor and linkage to have a load to work against before the spring clutch and eccentric cam will do their thing during the motor-reverse sequence.  If I'm feeling energetic after I get home from work tonight, I'll go back out to the garage and give it another try, this time with the blades installed. 

More tomorrow.

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A question I have about the tang, is it a 90deg bend or angled so it can drag when rotating but snag the opening?

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I believe the tang is bent 90 degrees. But do note that I've only ever seen pictures. The ones I've seen in person were all broken.

Namerow, good luck with the spring rewind. Maybe your new spring is parking, but you just can't tell. It's not a huge difference from the broken spring (aka "normal") operation. FSM says the normal operation is ninety-six degrees of sweep, and the "rise up angle" is five and a half degrees. Maybe you just can't tell the difference?

 

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Oh, and I believe the tang is always supposed to be positively engaged in the slot. It's not like it only snags the slot when running in reverse. It's always engaged.

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As I am today rebuilding another wiper linkage, I thought I would contribute some more detailed pictures of the fancy wiper park components for future posterity.

Out of, ahem, "several" available wiper linkages, I have only a single one that has an unbroken spring.

Thought I would include detailed pictures of it in hopes of some day creating new ones, as well as to show the assembly order and position of all the components

IMG_7284.JPG

Here is the little spring with oft-broken off hook engaged where it belongs

IMG_7307.JPG

Complete and broken example for comparison of where the break happens and how long the bent tang is

IMG_7309.JPG

Clever photography (ie move it around until you can see it), shows the shiny spots and wear on the bottom of the spring.

IMG_7311.JPG

All the bits and pieces in order from top to bottom. Top is defined as having the end with the (poor excuse for a ) snap ring/C-clip pointing up when you're taking it apart.

 I have used a real compatible sized E clip to replace that obnoxious soft C clip thing. 

IMG_7299.JPG

This gives you a visual idea of how the eccentric cam part fits with the hole in the arm, effectively changing  the arm length as the cam rotates. 

IMG_7296.JPG

Another shot showing how the spring and the "millennium falcon" part with the slot are arranged in the assembly.

Clearly this proves the designer of said space ship in the movie was a Datsun owner. 

 

 

Edited by zKars
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Glad you enjoyed today’s little treasure.

Now off to google “How to make small coil springs by hand”

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