mystery vacuum line?...Help
Thread Starter
Intermediate
Joined: Oct 2012
Posts: 49
Likes: 1
From: In The Garage
mystery vacuum line?...Help
Hi guys, I found a disconnected vacuum line on my 69 and was wondering where it connects. Sorry for the poor pictures it's really hard to get a good shot so I placed a blue pen pointing at the line, it seems to come out of the firewall.
Thanks
Thanks
Team Owner
Joined: Sep 2006
Posts: 31,283
Likes: 4,373
From: Westminster Maryland
Hi,
I believe it's the vacuum supply line that runs to the heater/defroster controller in the shifter console. It T's off the wiper door vacuum supply line
Regards,
Alan
This is a 71, I believe the T is in a slightly different place in 69.
I believe it's the vacuum supply line that runs to the heater/defroster controller in the shifter console. It T's off the wiper door vacuum supply line
Regards,
Alan
This is a 71, I believe the T is in a slightly different place in 69.
Last edited by Alan 71; Aug 2, 2014 at 10:31 AM.
Drifting
Joined: Jul 2006
Posts: 1,259
Likes: 154
From: Deplorableville Nebraska
Judging by the location next to the wiper door, and if it's next to two other vacuum lines, it is the wiper safety valve vent hose. If you take the wiper grill off, trace the hose and see if it goes to the valve.
If that is your guy, it is supposed to be vented to atmosphere.
If that is your guy, it is supposed to be vented to atmosphere.
Team Owner
Joined: Sep 2006
Posts: 31,283
Likes: 4,373
From: Westminster Maryland
Hi Dave,
If you look closely that hose has the grommet moulded as an integral part of the hose.
It doesn't push through a grommet as the hoses from the safety valve do.
It's also a smaller diameter and a different material than the vacuum hoses that are part of the wiper door system.
Regards,
Alan
You can see the 3 hoses from the safety valve and their large diameter grommet in this pic. (Again this is a 71.)
If you look closely that hose has the grommet moulded as an integral part of the hose.
It doesn't push through a grommet as the hoses from the safety valve do.
It's also a smaller diameter and a different material than the vacuum hoses that are part of the wiper door system.
Regards,
Alan
You can see the 3 hoses from the safety valve and their large diameter grommet in this pic. (Again this is a 71.)
Last edited by Alan 71; Aug 2, 2014 at 12:37 PM.
Team Owner
Joined: Sep 2006
Posts: 31,283
Likes: 4,373
From: Westminster Maryland
Hi EC,
I believe 69 cars have a large yellow striped vacuum supply hose that runs from the vacuum storage tank along the firewall behind the engine.
The T should be in that hose. It should have 2 large nipples and 1 small nipple. The small nipple is very easy to break off.
Regards,
Alan
I believe 69 cars have a large yellow striped vacuum supply hose that runs from the vacuum storage tank along the firewall behind the engine.
The T should be in that hose. It should have 2 large nipples and 1 small nipple. The small nipple is very easy to break off.
Regards,
Alan
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Drifting
Joined: Mar 2014
Posts: 1,744
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From: Akron OH
Hi Dave,
If you look closely that hose has the grommet moulded as an integral part of the hose.
It doesn't push through a grommet as the hoses from the safety valve do.
It's also a smaller diameter and a different material than the vacuum hoses that are part of the wiper door system.
Regards,
Alan
You can see the 3 hoses from the safety valve and their large diameter grommet in this pic. (Again this is a 71.)
If you look closely that hose has the grommet moulded as an integral part of the hose.
It doesn't push through a grommet as the hoses from the safety valve do.
It's also a smaller diameter and a different material than the vacuum hoses that are part of the wiper door system.
Regards,
Alan
You can see the 3 hoses from the safety valve and their large diameter grommet in this pic. (Again this is a 71.)
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
That is exactly what the "switch" that hose is connected to is supposed to PREVENT!! Definitely unplug it and if you still have the problem, then the the vacuum "switch" it is connected to may need adjustment or replacement.
Drifting
Joined: Jul 2006
Posts: 1,259
Likes: 154
From: Deplorableville Nebraska
That hose identified in your picture that is to be vented to the atmosphere has an obviously owner installed plug in the on my '71. I'm wondering why it was plugged by a prior owner and what the blockage of that hose caused a) not work at all or b) not work properly. I hope it changes the behavior of my wiper door as it goes down so fast that it closes on my wipers and prevents them from parking.
The real purpose of the open vent hose is to VENT the top cavity of the safety valve over the spring to try to prevent foreign material getting inside the valve when the plunger cycles. If you examine the 3 ports on the valve, only the bottom two are for any actuating function. The port closest to the white plunger is the vent.
If pulling the plug changes the behavior of your wiper door, you really have problems with how your hoses are connected. If your wiper door closes on your wipers, you have a defective relay, safety valve, or both.
If you want to know how to diagnose, let me know.
Drifting
Joined: Mar 2014
Posts: 1,744
Likes: 278
From: Akron OH
I cannot hardly count how many Bubba'd safety valve vent tubes I've seen over the years that have been plugged. Bubba1, Bubba2, Bubba3 or whoever since these cars were new somewhere just absolutely had to put a screw (most common), golf tee, or whatever to plug them. After all, if there is a hole, shouldn't there be a connection or plug?
The real purpose of the open vent hose is to VENT the top cavity of the safety valve over the spring to try to prevent foreign material getting inside the valve when the plunger cycles. If you examine the 3 ports on the valve, only the bottom two are for any actuating function. The port closest to the white plunger is the vent.
If pulling the plug changes the behavior of your wiper door, you really have problems with how your hoses are connected. If your wiper door closes on your wipers, you have a defective relay, safety valve, or both.
If you want to know how to diagnose, let me know.
The real purpose of the open vent hose is to VENT the top cavity of the safety valve over the spring to try to prevent foreign material getting inside the valve when the plunger cycles. If you examine the 3 ports on the valve, only the bottom two are for any actuating function. The port closest to the white plunger is the vent.
If pulling the plug changes the behavior of your wiper door, you really have problems with how your hoses are connected. If your wiper door closes on your wipers, you have a defective relay, safety valve, or both.
If you want to know how to diagnose, let me know.
Thanks,
Rick
Heel & Toe
Joined: Jul 2012
Posts: 17
Likes: 0
Similar question regarding wiper door issues
Hello, I was reading this chain and I am having a very similar issue. 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.
Thanks.
Ron
Thanks.
Ron