69 Vacuum Wiper Door
Thread Starter
Heel & Toe
Joined: Jul 2012
Posts: 17
Likes: 0
69 Vacuum Wiper Door
Hello, My wiper door doesn't close. For a week or so it would be closed when the car was off. When I started it up, still closed. But if I accelerated heavily, it would open for just 2-3 seconds, and then it would close back up, and would be fine. It repeated this cycle for a week or two. Now it just stays open. Does this ring a bell for anyone? Note my headlights work perfectly, they open and close correctly via the headlight on/off switch, and also open properly if I pull the headlight override switch. So it seems to be isolated to the wiper door part of the system. Any advice would be greatly appreciated.
Thanks.
Ron
Thanks.
Ron
Team Owner
Joined: Sep 2006
Posts: 31,280
Likes: 4,372
From: Westminster Maryland
Hi Ron,
It could be several things…
To start you may want to check the operation of the vacuum control valve that's mounted in the right side of the wiper bay. It's black plastic with a button and vinyl 'bellows' at one end. It has 3 small vacuum hoses hooked to it.
When the wiper arms move to the 'park' position the right side arm pushes a button that signals that the arms are fully down and the door can close without hitting them. The wiper door vacuum relay won't operate until it receives that signal.
To do a simple test of the valve you need some sort of vacuum pump with gauge like a Mity-Vac. Do you happen to have one?
If the control vale checks out the vacuum relay for the wiper door would be the next thing to check.
Regards,
Alan
It could be several things…
To start you may want to check the operation of the vacuum control valve that's mounted in the right side of the wiper bay. It's black plastic with a button and vinyl 'bellows' at one end. It has 3 small vacuum hoses hooked to it.
When the wiper arms move to the 'park' position the right side arm pushes a button that signals that the arms are fully down and the door can close without hitting them. The wiper door vacuum relay won't operate until it receives that signal.
To do a simple test of the valve you need some sort of vacuum pump with gauge like a Mity-Vac. Do you happen to have one?
If the control vale checks out the vacuum relay for the wiper door would be the next thing to check.
Regards,
Alan
Last edited by Alan 71; Aug 10, 2014 at 04:15 PM.
Drifting
Joined: Jul 2006
Posts: 1,259
Likes: 154
From: Deplorableville Nebraska
Ron,
I apologize for not getting back to you sooner. I've been working on a website for vacuum troubleshooting and I should have it up later this week. Here's how to check your safety valve.
1 - Remove your wiper grill, should have 8 screws and it will lift off.
2 - Mark and remove the 2 actuating vacuum hoses (5/16) from the wiper door actuator.
3 - Carefully lift up on the wiper door, and pull it up about halfway.
4 - You will find the safety valve underneath the passenger wiper arm close to the base. It looks like this;
5 - Ignore the port and it's hose nearest to the plunger. It is only a vent. It shouldn't be plugged.
6 - Hook up your Mityvac to the middle port, and mark the hose.
7 - Disconnect and block the bottom port. I use a short section of hose (3/16) with a plug in one end.
8 - Pump up your Mityvac. It should evacuate all vacuum and hold it. My guess is yours will fail this test.
9 - If you pass the #8 test, reconnect the bottom hose. Activate the wipers and stop them with the override in the up position. With the Mityvac still connected to the middle port, pump it up again. It should hold vacuum.
Report back.
ps where are you located?
I apologize for not getting back to you sooner. I've been working on a website for vacuum troubleshooting and I should have it up later this week. Here's how to check your safety valve.
1 - Remove your wiper grill, should have 8 screws and it will lift off.
2 - Mark and remove the 2 actuating vacuum hoses (5/16) from the wiper door actuator.
3 - Carefully lift up on the wiper door, and pull it up about halfway.
4 - You will find the safety valve underneath the passenger wiper arm close to the base. It looks like this;
5 - Ignore the port and it's hose nearest to the plunger. It is only a vent. It shouldn't be plugged.
6 - Hook up your Mityvac to the middle port, and mark the hose.
7 - Disconnect and block the bottom port. I use a short section of hose (3/16) with a plug in one end.
8 - Pump up your Mityvac. It should evacuate all vacuum and hold it. My guess is yours will fail this test.
9 - If you pass the #8 test, reconnect the bottom hose. Activate the wipers and stop them with the override in the up position. With the Mityvac still connected to the middle port, pump it up again. It should hold vacuum.
Report back.
ps where are you located?
Team Owner
Joined: Sep 2006
Posts: 31,280
Likes: 4,372
From: Westminster Maryland
Hi Ron,
1. With the button pushed IN…. the unmarked nipple should be closed and thus hold vacuum. The other 2 nipples (red/white) should be open and thus not hold vacuum.
2. With the button OUT….the white marked nipple should hold vacuum. The red marked nipple and the unmarked nipple should be open and thus not hold vacuum.
3. The nipple with the red mark is open no matter if the button is in or out.
Regards,
Alan
Hi, I see Dave has replied so disregard this test method..
1. With the button pushed IN…. the unmarked nipple should be closed and thus hold vacuum. The other 2 nipples (red/white) should be open and thus not hold vacuum.
2. With the button OUT….the white marked nipple should hold vacuum. The red marked nipple and the unmarked nipple should be open and thus not hold vacuum.
3. The nipple with the red mark is open no matter if the button is in or out.
Regards,
Alan
Hi, I see Dave has replied so disregard this test method..
Last edited by Alan 71; Aug 10, 2014 at 04:48 PM.
Thread Starter
Heel & Toe
Joined: Jul 2012
Posts: 17
Likes: 0
Thank you Alan and Dave, very helpful. I will troubleshoot this weekend. One other question: If I were to bypass the wiper door safety valve, meaning connect the tube going to the bottom to the tube going to the middle, would that theoretically rule out whether or not the switch was the issue? I would assume in doing this bypass, I should be able to open and close the door using the override switch under the steering wheel. The only problem with this hook up would be in turning off the wipers, while the door is still open, but just to troubleshoot would this be a helpful test?
Thanks again.
Ron
Thanks again.
Ron
Drifting
Joined: Jul 2006
Posts: 1,259
Likes: 154
From: Deplorableville Nebraska
If I were to bypass the wiper door safety valve, meaning connect the tube going to the bottom to the tube going to the middle, would that theoretically rule out whether or not the switch was the issue? I would assume in doing this bypass, I should be able to open and close the door using the override switch under the steering wheel. The only problem with this hook up would be in turning off the wipers, while the door is still open, but just to troubleshoot would this be a helpful test?
Long answer, maybe. There are 3 separate valves (switches) that can eliminate vacuum in the control hose going to the wiper door relay. The relay moves the actuating vacuum to the actuator ports front and rear by vacuum/no vacuum to the control (small) port. If by bypassing the safety valve the door still stays up, there are other issues that cannot be diagnosed this way.
It's always best if you can test each component for vacuum leaks separately mimicking their actual operation.
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Thread Starter
Heel & Toe
Joined: Jul 2012
Posts: 17
Likes: 0
One more question on this: should the wiper door stay closed when the car is off, and if so, what is causing it to stay closed? My understaning is the vacuum pulls the door closed, but when the car is off , is there a steady vacuum there to keep it closed, if so how, and if thats not what keeps it closed when the car is off, then what does keep it closed? Thx
Team Owner
Joined: Sep 2006
Posts: 31,280
Likes: 4,372
From: Westminster Maryland
Hi Ron,
Originally the vacuum system was so leak free that the doors and headlights could even be operated the next day after the engine was shut off using the vacuum from the storage tank.
The system is designed so that as vacuum is lost in either the control side, (small hoses, switches and relays), or servo side, (large hoses, and actuators), the doors stay where there are as the vacuum is lost.
Winking headlights and a dancing wiper door are the result of components not working the way they were intended.
Regards,
Alan
Originally the vacuum system was so leak free that the doors and headlights could even be operated the next day after the engine was shut off using the vacuum from the storage tank.
The system is designed so that as vacuum is lost in either the control side, (small hoses, switches and relays), or servo side, (large hoses, and actuators), the doors stay where there are as the vacuum is lost.
Winking headlights and a dancing wiper door are the result of components not working the way they were intended.
Regards,
Alan