I've been working on this for several weeks but can't find the problem. I printed out the Service Bulletin (March 11, 1968) and used it as a trouble shooting guide. With the info available on the Wilcox site, I confirmed my wiper switch on the dash and external relay under the center console are good. I also confirmed my vacuum motor solenoid attached to the tach housing is working as I can hear it. My motor runs at the lo and high settings, but when I turn it to the off position it continues to run, turning the wipers so they simply "budge" a bit up and down (not full sweeps like when the switch is on Lo). According to the Service Bulletin, I jumped the external relay as shown in Fig. 4 but the motor continued to do the same thing. The Bulletin says the external relay is bad, but it tested good. The Service Bulletin then says the dash switch or wiring to switch is bad. I know the switch tested good, and I have faith in the wiring. This is a 24K mileage car (I'm the second owner) and the wiring under the dash looks great and has not been touched. I'm beginning to think it may be the pawl in the wiper motor that "parks" the wipers. Before I get into the motor, I wanted to check with you for any other suggestions. Thank You for your help!

 

I had a motor that wouldn’t park. The c clip that held the gear, bushing and shaft together wasn’t in the slot so it was a bit sloppy....I would go back to the Willcox site and do the bench test with the motor installed. And the blades disconnected. If you don’t spray water on the window you may not get the wipers to slide easily enough to park...every so often mine just keeps bumping like that until it decides to park..it pretty random. If there were in issue in the wiper system it wouldn’t work at all, especially in a 68.

 

Thank you; I'll give it a try and report back.

 

I'd upload this. http://repairs.willcoxcorvette.com/w...-schematic.pdf

And I'd also search here: http://repairs.willcoxcorvette.com/?...&s=wiper+motor

With all this you should be able to figure your issue out.

Wiper Motor Bench Test 68 Ver 1


Wiper Motor Bench Test 68 Ver 2 "Follow up"


Great threads on 68 Wiper motors can be found here:

Mister Willcox, 68 wiper motor

68 wiper problems


Willcox

18243

 

Thank you Wilcox! I'll get back to it next week and report back.

 

Sorry, I can't help, but a comment. The 1968 Corvettes were produced in large numbers. They are relatively rare today. My opinion is that they had so many problems that they were shunted off to oblivion. A prinicpal problem was the windshield wiper electrical and vacuum system. Other problems were minor things such as the body panels didn't match up, the convertible softops had problems, and the optional convertible hardtops....forget them..they really didn't fit.

In the late 70's, I had so much problems with the windshield wipers, that I converted my 68 wipers to the 69 wiper system.......this was surprisingly a complicated solution....but I did get them to work correctly a la 69. In the 2004 era when I restored my 68, I installed new 68 lectric limited engine compartment wriing harnesses, new 68 dash board harnesses, and a restored 68 windhield wiper motor. I have never tried to turn on my 68 wipers......I'm just not yet prepared to accept, that as in the 1970's, they don't work.

 

mine work. I have just developed a hiccup and its the wiper park switch failing. No big deal. I can fix it and it'll work again. It just takes a bit of time before the light comes on and you understand how they made the system...68 was pretty basic, it just took some engineers to start adding stuff to make it more and more complicated...I think it was the PCP finally kicking in....

My suggestion is, if you want it to work and a part needs to be replaced, get it from Willcox, he only sells stuff that works and his parts are US made by his company, and resold by other vendors..If it isnt from willcox, it probably isnt going to work for long....

 

I tried spraying water on the windshield but the blades still would not park. I do appreciate your suggestions and ideas. Now I'll go to more Wilcox videos. If any of the engineers had an inkling we'd be driving these cars 50 years later they probably would have left the wipers exposed and dumped the system. However, I also have a C-2 and I prefer the vacuum headlights to the electric motor ones...

 

I mentioned your problem to Ernie and he said your wiper park switch is probably toasted. You can test it and if its bad you have 2 choices,....
1.spend the time and energy of trying to replace the switch in your existing motor
2. replace the motor and save our self the aggravation of trying to replace the switch and spend that time out driving the car and having fun...

 

Thanks Rescue Rogers. I'll probably have my motor rebuilt by Wilcox if that is the problem given my car is all original. Interesting tidbit: took the car for a ride yesterday and turned the wipers off with rotating switch under the speedo cluster. I attempted to stop the wipers in their closed position. After my ride, I turned off the car and then disconnected the battery. Upon disconnecting the battery, the wiper cover closed! I'm assuming I had the motor at the "parked" position and that allowed the vacuum system to close the cover???

 

With this setup you never know....

 

First off, a big thank you to Willcox Corvette for all their instructions and videos relative to diagnosing the ’68 wiper system.



I following all the Willcox testing for relays and switches, and final took out the motor. My motor will not park.



When bench testing, the motor runs fast (doesn’t seem quite as fast as hi speed) without contact 1 & 3 grounded. However, it looks like it’s trying to park. When grounding 1 & 3, the park arm is retracted and it runs low speed. When removing 3 from ground, it runs high speed. When reconnecting 3 to ground and removing 1 from ground, it runs fast as before and attempts to park but keeps on running. The parking arm comes out and engages, but the motor does not turn off.



Can I repair this motor? If not, who do you recommend for a high quality rebuilt or new? Should I consider a rebuilt or just get new? The car is a very low mileage all original, so I’d prefer to fix the motor I have if possible.

 

I've got the park switch pulled out of the motor. I assume that's my problem. Can this be rebuilt? Someone referred to points, but I can't see any in the housing.

 

Hi Ernie of Willcox. I'd appreciate your recommendations to above.

Thanks!!

 

Update. I started to look at the park switch and I found the points. I realized the lever was not actuating the points. There is a yellow plastic(?) pad that sits on the spring copper that the points are on. The lever in the park switch comes down and hits the yellow pad, thereby opening the points and parking the wipers. The lever was loose and would slip past the yellow pad. I carefully bent the lever and now it seems to hit the yellow pad and open the points.

Time for another bench test!

 

If you remember post some pictures before you put it all back together.... just for future info.

 

Awesome... Give it a test and see what happens... Post back. (with pics lol).

If the park switch is bad you can usually scavenge one from a different motor from the same or close years... If you need help finding one if it doesn't work, I can probably find you a list of what years used this.

I stopped rebuilding these motors about 5 years ago when the cost exceeded the expected price. Then the new motors came out without a core and that was even better. Thus my statement that the cost to have it rebuilt yourself will exceed the cost of a new or rebuilt motor. I hope this help you understand and a guy in sales told me you called... But I hang out in the service department most of the day and there are no phones out here (by design).... I can't pull someone off a car if I'm not here... Sorry.

E

 

Thank you Ernie for your comments. I did bench test the motor and all works fine. Kind of a thrill to se it actually park! I'm posting pics with some comments to hopefully help others.

The 1st pic is the motor with the washer pump removed.

2nd pic shows the parking switch removed and on its side. You can see the lever with the spring attached.

3rd pic is looking in the contact hole. You can see the contact is now open as the copper spring bar is pushed down and visible in the opening.

4th and 5th pics are both looking at the yellow plastic rectangular piece mounted on the copper spring bar. This is where the lever contacts the bar to open the points.

My lever appeared to be bent and would slide past the yellow piece and therefore not depress the bar and open the points. Using a long nosed pliers, I bent it slightly and now contact is made and the points open. Not sure how mine could have gotten bent; more likely it became a bit worn on the shaft and was a bit wobbly. The small spring is very important as it helps keep the lever in place so it contacts the yellow piece.

I'm no electrician, but this is really a mechanical/electric switch, so easy to understand how it works. The challenge is to see inside with the black plastic housing obscuring the view of the copper spring bar and points.

Getting the motor out took more time than the fix. Manual says just remove 3 nuts, but good luck pulling it away from the firewall with the ignition shielding there! I had to pull the shielding up out of the way, which required getting the spark plug wires up out of the way...

But alls well that ends well.

Reassembly tomorrow.

 

And for those that may be interested, a few pics of my car.

 

very cool