69 Wiper Door problem
Burning Brakes
Joined: Dec 2008
Posts: 971
Likes: 45
From: Middlesex NJ
Ten valves received and tested. Ten valves failed.... All valves hold vacuum on the lower port but leak from the middle port.
In the door vacuum system.... as far as operation:
When the wipers are turned on the tach solenoid blocks vacuum to this relay, the lack of vacuum at the relay will cause the door to open. When the door opens the limit switch is pushed and the motor runs. So while running the middle port is not blocking vacuum, the lower port is… but there will not be any vacuum there because of the tach solenoid is already blocking it.
When you turn off the wipers, the solenoid opens allowing vacuum to this switch, the arm comes down push the plunger which now ports the vacuum to the relay. The relay gets vacuum and will close.
So what's this mean...
It means the valves will work and function as designed while in operation. However, (The OP has found out the hard way) when in the closed position the vacuum will leak off the system from the middle port. (They are leaking out the top under the cap, not the top nipple) If the large hose side is in proper working order, the door will rise. The only way to stop this would be to place a one way check valve between the valve and the top of the relay.
You can test the relay for this issue by applying vacuum to the middle port and covering the lower one with your finger, the relay should hold vacuum this way.
If the large hose is not in good shape and leaking vacuum, the door will probably stay shut and the defect goes un-noticed. This is why few are complaining now about the newest run of valves..
In the door vacuum system.... as far as operation:
When the wipers are turned on the tach solenoid blocks vacuum to this relay, the lack of vacuum at the relay will cause the door to open. When the door opens the limit switch is pushed and the motor runs. So while running the middle port is not blocking vacuum, the lower port is… but there will not be any vacuum there because of the tach solenoid is already blocking it.
When you turn off the wipers, the solenoid opens allowing vacuum to this switch, the arm comes down push the plunger which now ports the vacuum to the relay. The relay gets vacuum and will close.
So what's this mean...
It means the valves will work and function as designed while in operation. However, (The OP has found out the hard way) when in the closed position the vacuum will leak off the system from the middle port. (They are leaking out the top under the cap, not the top nipple) If the large hose side is in proper working order, the door will rise. The only way to stop this would be to place a one way check valve between the valve and the top of the relay.
You can test the relay for this issue by applying vacuum to the middle port and covering the lower one with your finger, the relay should hold vacuum this way.
If the large hose is not in good shape and leaking vacuum, the door will probably stay shut and the defect goes un-noticed. This is why few are complaining now about the newest run of valves..
What am I doing wrong.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Willcox
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
And because of the video posted above, all the new reproduction valves are defective.
The company that makes the valves decided that my video was not correct... and this one was...
No disrespect intended, there is nothing quick about making one of them and it's a great job...
However, he should have tested from the middle port.
The vacuum path is from the middle pulling to the lower. Testing from the lower port will tell you the valve will block vacuum to the relay, but it won't tell you if the valve itself will hold vacuum. The manufacturer didn't understand the importance of this when he we had them re-made...
The newest reproduction valves do block vacuum to the relay on the lower port and the door does open like it should.
The issue… is the newest valves leak vacuum on the middle port! The newest valves leak it out of the top of the valve. If you test a valve you must test it from the center port thus assuring yourself the valve is sealed entirely.
What does this mean? When the new valves are in place, the entire time you have your wipers are on or off; you will have a vacuum leak… When you turn the wipers off the vacuum drains instantly off the small side hose and your door will open.
The exception: On cars that have a large hose system that isn’t all snug and tight this issue (aside from the constant vacuum leak) will probably go un-noticed. If you are leaking vacuum on the large hose side and it leaks off before the door can open. On cars that have good functioning and operating large hose side… Your door is going to pop up.
The company that makes the valves decided that my video was not correct... and this one was...
No disrespect intended, there is nothing quick about making one of them and it's a great job...
However, he should have tested from the middle port.
The vacuum path is from the middle pulling to the lower. Testing from the lower port will tell you the valve will block vacuum to the relay, but it won't tell you if the valve itself will hold vacuum. The manufacturer didn't understand the importance of this when he we had them re-made...
The newest reproduction valves do block vacuum to the relay on the lower port and the door does open like it should.
The issue… is the newest valves leak vacuum on the middle port! The newest valves leak it out of the top of the valve. If you test a valve you must test it from the center port thus assuring yourself the valve is sealed entirely.
What does this mean? When the new valves are in place, the entire time you have your wipers are on or off; you will have a vacuum leak… When you turn the wipers off the vacuum drains instantly off the small side hose and your door will open.
The exception: On cars that have a large hose system that isn’t all snug and tight this issue (aside from the constant vacuum leak) will probably go un-noticed. If you are leaking vacuum on the large hose side and it leaks off before the door can open. On cars that have good functioning and operating large hose side… Your door is going to pop up.
Last edited by Willcox Corvette; May 31, 2014 at 05:01 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
