Help with Wipers (mechanical operation)
Thread Starter
Heel & Toe
Joined: Jul 2007
Posts: 19
Likes: 0
Help with Wipers (mechanical operation)
I have never watched C3 wipers work. Amazingly, I have gotten a grasp on the electrical part of windshield wipers on my 1968, but I am having trouble with the mechanical operation.
On my car, the motor turns, but the drive stud from the motor that attaches to the arm that drives the wipers does not spin, but it moves in a circular motion like on an eccentric. With the wiper arm disconnected, I manually operated them with my hands, and it appears that the stud mentioned above should spin to make it work correctly.
Can anyone offer any insight as to how this should work? Can you tell me about the stud that seems to be attached to the gear in the wiper motor gearbox?
Thanks,
Brian
On my car, the motor turns, but the drive stud from the motor that attaches to the arm that drives the wipers does not spin, but it moves in a circular motion like on an eccentric. With the wiper arm disconnected, I manually operated them with my hands, and it appears that the stud mentioned above should spin to make it work correctly.
Can anyone offer any insight as to how this should work? Can you tell me about the stud that seems to be attached to the gear in the wiper motor gearbox?
Thanks,
Brian
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
I suspect you have a warn out gear inside the wiper transmission. Below are a couple of poor quality pictures of what you see when you remove the black plastic cover. There is a worm gear on the end of the motor that drives the big plastic gear on the wiper shaft. Pull the cover off and see what you have. The shaft you see on the linkage side is attached to the big plastic gear shown here. The gear also serves as a cam for the park circuit. This is from a 78'.
Last edited by Duke94; Nov 9, 2008 at 02:17 PM.
Team Owner
Joined: Sep 2006
Posts: 31,160
Likes: 4,241
From: Westminster Maryland
Hi Brian,
I believe the shaft that comes out of the wiper motor does spin normally, but the crank arm that attaches to it in the wiper bay moves like an eccentric. You can JUST see the ARM in this picture, it's under the bracket for mounting the wiper bay grill and JUST forward of the connection for the wiper transmission arms.
Regards,
Alan
I believe the shaft that comes out of the wiper motor does spin normally, but the crank arm that attaches to it in the wiper bay moves like an eccentric. You can JUST see the ARM in this picture, it's under the bracket for mounting the wiper bay grill and JUST forward of the connection for the wiper transmission arms.
Regards,
Alan
Thread Starter
Heel & Toe
Joined: Jul 2007
Posts: 19
Likes: 0
Thank you for the replies.
I opened the motor/gearbox, and the gears appear to be okay. Judging by the way the shaft goes through the gear, it should not spin. If it is moving correctly, and simply moves like an eccentric without spinning, then I have other problems.
Alan 71, it looks like the arm is mounted to the motor shaft like yours (but nowhere near as clean or nice). I am reassembling pieces that were disassembled well over a year ago, and all of my notes are gone.
One other thing that I noticed is that when the wiper motor rotates, the wipers move about four inches up the windshield and then back down.
I opened the motor/gearbox, and the gears appear to be okay. Judging by the way the shaft goes through the gear, it should not spin. If it is moving correctly, and simply moves like an eccentric without spinning, then I have other problems.
Alan 71, it looks like the arm is mounted to the motor shaft like yours (but nowhere near as clean or nice). I am reassembling pieces that were disassembled well over a year ago, and all of my notes are gone.
One other thing that I noticed is that when the wiper motor rotates, the wipers move about four inches up the windshield and then back down.
Le Mans Master
Joined: Jun 2005
Posts: 5,447
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From: Syracuse NY
Burning Brakes
Joined: Jul 2008
Posts: 876
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From: Canastota Ny
yeah the lead over the years has taken hold finally! i traded my mustangs in for a vette. i think i got smarter! You just watch out for a "munchkin" or two in that engine compartment this winter!
Le Mans Master
Joined: Jan 2006
Posts: 8,246
Likes: 114
From: Watkins Glen NY
Hi Brian,
I believe the shaft that comes out of the wiper motor does spin normally, but the crank arm that attaches to it in the wiper bay moves like an eccentric. You can JUST see the ARM in this picture, it's under the bracket for mounting the wiper bay grill and JUST forward of the connection for the wiper transmission arms.
Regards,
Alan
I believe the shaft that comes out of the wiper motor does spin normally, but the crank arm that attaches to it in the wiper bay moves like an eccentric. You can JUST see the ARM in this picture, it's under the bracket for mounting the wiper bay grill and JUST forward of the connection for the wiper transmission arms.
Regards,
Alan
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Le Mans Master
Joined: Jun 2005
Posts: 5,447
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From: Syracuse NY
[QUOTE=1nicecorvette;1567789540]yeah the lead over the years has taken hold finally! i traded my mustangs in for a vette. i think i got smarter! You just watch out for a "munchkin" or two in that engine compartment this winter![/QUOTE]
Took me a second to get that.
Sorry for the highjack guys.
Took me a second to get that.
Sorry for the highjack guys.
Team Owner
Joined: Sep 2006
Posts: 31,160
Likes: 4,241
From: Westminster Maryland
Hi Brian,
I'm not sure what you mean by the wiper arms moving 4 inches.
I believe the wiper transmission arms move left to right about 4 inches in the wiper well, but that should move the wiper arms and wiper blades through a full cycle on the windshield.
Regards,
Alan
I'm not sure what you mean by the wiper arms moving 4 inches.
I believe the wiper transmission arms move left to right about 4 inches in the wiper well, but that should move the wiper arms and wiper blades through a full cycle on the windshield.
Regards,
Alan
Le Mans Master
Joined: Jan 2007
Posts: 5,485
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From: Peekskill NY
Check the spline studs the wiper arms mount on. Those fine teeth can be stripped over time and only move the wipers partially. I needed to replace the drivers side on mine when I bought it. Bubba drilled a hole in the top of the arm and drove a steet metal screw into the stud so the wiper would work but wouldn't park completely down below the grill when off.
You can see it sticking up in this pic.
Got a replacement from a vett salvage yard for 40 bucks and is fine now.
Glenn
You can see it sticking up in this pic.Got a replacement from a vett salvage yard for 40 bucks and is fine now.
Glenn
Team Owner
Joined: Jul 2004
Posts: 40,332
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From: Redondo Beach, California
The wipers have three "states" of operation. One state is when they are completely off, the wiper blades are completely down and rest on the wiper stop brackets (Off). The next state is, just to coin a word, the "arm" state. In the arm state, the wiper blades move up about two or three inches above the stop brackets and stop remaining motionless. The third state is the obvious "operate" state where they move back and forth.
The "arm" state is most apparent on intermittent wipers: the wipers operate for a few cycles and then stop at the arm position for a few moments and then operate again.
On the 68 to 72 wiper system, the wiper motor is in the "arm" state only for a very brief time (a second or so?). The wiper compartment door complicates the wiper system. When you turn your wipers off, the wipers cycle to the "arm" state for just a brief second of so, but the wiper compartment door must remain open or it'll jamb against the wipers. Only after the wipers collapse to the Off state can the door then close.
The "arm" state is most apparent on intermittent wipers: the wipers operate for a few cycles and then stop at the arm position for a few moments and then operate again.
On the 68 to 72 wiper system, the wiper motor is in the "arm" state only for a very brief time (a second or so?). The wiper compartment door complicates the wiper system. When you turn your wipers off, the wipers cycle to the "arm" state for just a brief second of so, but the wiper compartment door must remain open or it'll jamb against the wipers. Only after the wipers collapse to the Off state can the door then close.
Thread Starter
Heel & Toe
Joined: Jul 2007
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Once again, thanks to all for your input. 68/70 Vette, I think you are in the right area. My motor may have gone to the "arm" state, but would not go any further.
I opened the motor/gearbox again, and found that the solenoid near the wiper park switch is weak. It should hold a latch back to allow the center to rotate. That same solenoid also enables the run circuit to by-pass the park circuit, and it seemed to do that, but the latch would not stay off of the center arm. This caused the gear to rotate, but would not allow the center to rotate with it; therefor, the stud looked like it was on an eccentric and would not spin.
I think that I know where to go from here. Thank you for your help.
I opened the motor/gearbox again, and found that the solenoid near the wiper park switch is weak. It should hold a latch back to allow the center to rotate. That same solenoid also enables the run circuit to by-pass the park circuit, and it seemed to do that, but the latch would not stay off of the center arm. This caused the gear to rotate, but would not allow the center to rotate with it; therefor, the stud looked like it was on an eccentric and would not spin.
I think that I know where to go from here. Thank you for your help.
