Wiper door issues
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
Try this one.
http://lbfun.com/Corvette/Tech/vette...m%20System.pdf
Here's the schmatic.
http://lbfun.com/Corvette/Tech/vette...les/vacuum.pdf
Here's a book you can buy.
http://www.vettevacuum.com/troubleshooting_guide.htm
http://lbfun.com/Corvette/Tech/vette...m%20System.pdf
Here's the schmatic.
http://lbfun.com/Corvette/Tech/vette...les/vacuum.pdf
Here's a book you can buy.
http://www.vettevacuum.com/troubleshooting_guide.htm
Last edited by Duke94; Jan 18, 2007 at 06:52 PM.
Melting Slicks
Joined: Jan 2007
Posts: 2,589
Likes: 5
From: Salisbury Maryland
Mine doesn't operate at all. I've been fixing everything else on the car to my liking, but the wiper door is next on the list. I have the schematic and troubleshooting guide and I am also skilled in fluid power, so after briefly looking over the diagram, it's not scaring me away. I think my problem is the actuator. I can move it with a screwdriver, but it's pretty stiff. I put a little Super Lube on the shaft and that didn't help.
Let's tackle this together!
I have a Mity-vac so that I can test the components too.
Anyone have a good starting point?
My headlights work fine, so I know that that half of the system works properly.
Any input would be helpful.
Let's tackle this together!
I have a Mity-vac so that I can test the components too.
Anyone have a good starting point?
My headlights work fine, so I know that that half of the system works properly.
Any input would be helpful.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
Vacuum opens and closes the wiper door via the actuator and the relay. Wiper operation is electrical and is tripped mechanically as the wiper door opens and the lever pushes on the underhood switch.
Your troubleshooting should be limited to good vacuum, possible adjustment of the actuator rod from the actuator to the wiper door, and possible adjustment of the wiper switch trip lever.
My advice is to disconnect the vacuum lines from the actuator which will allow you to open and close the wiper door by hand. Make your rod and switch adjustments as needed and check them by moving the door by hand.
Once those adjustments are made, reattach the vacuum hoses and troubleshoot the vacuum system.
Don't forget the override beneath the steering column.
Your troubleshooting should be limited to good vacuum, possible adjustment of the actuator rod from the actuator to the wiper door, and possible adjustment of the wiper switch trip lever.
My advice is to disconnect the vacuum lines from the actuator which will allow you to open and close the wiper door by hand. Make your rod and switch adjustments as needed and check them by moving the door by hand.
Once those adjustments are made, reattach the vacuum hoses and troubleshoot the vacuum system.
Don't forget the override beneath the steering column.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
In case you aren't familiar with it, there is an electro-pneumatic solenoid valve mounted to the back of the tachometer on early 70's C3's [at least] which is a common problem. Sometimes it is a vacuum line that has come off...sometimes it's the solenoid part that goes bad. Just be aware that one of the wiper door components lurks behind the tach.
Melting Slicks
Joined: Jan 2007
Posts: 2,589
Likes: 5
From: Salisbury Maryland
My wiper door actuator is very stiff. It's almost like it's partially seized, that's why I think that's the problem. It's very difficult to move by hand or with screwdriver. The diaphram could be shot, it sat a few years. I'm going to take it off today and test it with the Mity-vac. I've already traced lines and didn't find a disconnect.
Advanced
Joined: Dec 2006
Posts: 57
Likes: 0
From: Flanders NJ
You might want to check that the door itself isn't binding. A little corrosion on the hinge(s) wold make the whole system seem stiff. If memory serves me, there are also nylon washers /bushings/grommets that could break or bind. Remember: its all interconnected,so check each component separately and start with the simple stuff first. Good luck...joe
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Disconnect the vaccum lines when you move the door by hand. The diaphragm seals can be damaged by moving the door. Same for the headlights. One of the guys in my corvette club pulled my headlight up looking for the headlight washer, that headlight never came up again on its own. I replaced the seals and it works good. Just food for thought.
Another thing I found out is the bolts that hold the door must be of the shouldered kind. The previous owner of my car had just used some hardware he picked up at Home Depot or where ever, and tightened them down. My door would not come up either. I replaced his mess with the correct hardware and that corrected some of the wiper system problems my car had.
Another thing I found out is the bolts that hold the door must be of the shouldered kind. The previous owner of my car had just used some hardware he picked up at Home Depot or where ever, and tightened them down. My door would not come up either. I replaced his mess with the correct hardware and that corrected some of the wiper system problems my car had.
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Melting Slicks
Joined: Jan 2007
Posts: 2,589
Likes: 5
From: Salisbury Maryland
Well, I've pulled out the actuator and here's what I've found. 1) The wiper door moves relatively easily by hand, that is, moving the rod in and out. 2) The actuator rod moves freely, but doesn't hold air/vacuum. It's allowing air to bypass via the diaphram. So, it appears shot. That is, it should move when I apply vacuum to one side or the other. It doesn't. So, off I go to $100 land(CC or Eckler's).
Well at least the system will work properly when the new one is on.
Well at least the system will work properly when the new one is on.
Thread Starter
Intermediate
Joined: Feb 2006
Posts: 39
Likes: 0
Did not know...
In case you aren't familiar with it, there is an electro-pneumatic solenoid valve mounted to the back of the tachometer on early 70's C3's [at least] which is a common problem. Sometimes it is a vacuum line that has come off...sometimes it's the solenoid part that goes bad. Just be aware that one of the wiper door components lurks behind the tach.
Thread Starter
Intermediate
Joined: Feb 2006
Posts: 39
Likes: 0
Actuator replacement
Well, I've pulled out the actuator and here's what I've found. 1) The wiper door moves relatively easily by hand, that is, moving the rod in and out. 2) The actuator rod moves freely, but doesn't hold air/vacuum. It's allowing air to bypass via the diaphram. So, it appears shot. That is, it should move when I apply vacuum to one side or the other. It doesn't. So, off I go to $100 land(CC or Eckler's).
Well at least the system will work properly when the new one is on.
Well at least the system will work properly when the new one is on.
Thread Starter
Intermediate
Joined: Feb 2006
Posts: 39
Likes: 0
Checking Hardware
Disconnect the vaccum lines when you move the door by hand. The diaphragm seals can be damaged by moving the door. Same for the headlights. One of the guys in my corvette club pulled my headlight up looking for the headlight washer, that headlight never came up again on its own. I replaced the seals and it works good. Just food for thought.
Another thing I found out is the bolts that hold the door must be of the shouldered kind. The previous owner of my car had just used some hardware he picked up at Home Depot or where ever, and tightened them down. My door would not come up either. I replaced his mess with the correct hardware and that corrected some of the wiper system problems my car had.
Another thing I found out is the bolts that hold the door must be of the shouldered kind. The previous owner of my car had just used some hardware he picked up at Home Depot or where ever, and tightened them down. My door would not come up either. I replaced his mess with the correct hardware and that corrected some of the wiper system problems my car had.
