Windshield wiper door

[ttop70]

Hi Corvette Kotze. I'm new here. I have a 1970 and the windshield wiper cover starts to come up after the car sits for a couple of days. Some people say it's normal, but is seems to be getting worse now that the years have crept up on it. Could it be the vacuum lines or the vacuum tank? Or the vacuum diaphragm? Or all of the above? Thanks. What kind of Corvette do you own?

[rayfan]

In my humble opinion it could be all. But I would pay special attention to the wiper door actuator.

[MKOTZE]

Originally posted by ttop70
Hi Corvette Kotze. I'm new here. I have a 1970 and the windshield wiper cover starts to come up after the car sits for a couple of days. Some people say it's normal, but is seems to be getting worse now that the years have crept up on it. Could it be the vacuum lines or the vacuum tank? Or the vacuum diaphragm? Or all of the above? Thanks. What kind of Corvette do you own? Hello TTop70 and welcome to the forum. I'm sorry it took so long to get back to you on this but I've been working on four different corvettes so I wasn't on the forum too much. So let's see The wiper door is controlled by a vacuum actuator. In order to have the wiper door open by itself when not running you would have to have a vacuum leak on the control side of the system. The parts involved are the relay valve, vacuum control solenoid, vacuum override valve,and the interlock valve and the vacuum hoses going to those parts. The relay valve is the main control of the system. When the vacuum is shut off from the system by one of the previously mentioned valves a spring inside the relay valve moves a piston inside the valve that allows vacuum to be applied to the vacuum actuator on the wiper door which will cause the door to open. Therefore, you know that the vacuum actuator and the vacuum source tank are not the problem. You could have a vacuum leak at the diaphram on the relay valve or a leak at the hoses. One way to diagnose the problem further is to take a needle nose vicegrip and pinch the vacuum hose going to the diaphram of the relay valve after the vehicle is turned off and the wiper door is closed. This will test the relay valve. If the door remains closed then the relay valve is functioning properly. If the door opens then the leak would have to be in the relay valve. The vacuum relay valve is mounted on the firewall near the brake master cylinder. The vacuum control solenoid is part of the wiper switch. The vacuum override valve is located at the lower edge of the dash by the steering column. The interlock valve is located under the wiper door connected to the wiper arm linkage. You could use the same procedure to test each valve in the order listed, each time noticing if the door opens. If the door opens which ever valve you are testing is where the leak is. I hope this helps and if you have any other questions let me know.Good luck. :chevy: MKOTZE

[ttop70]

Bingo! The vacuum override valve has a leak. Not only that all the hoses seemed very dry, so I'm going to replace them all. Using the vice grip was an excellent suggestion. Thank you.

You know I bought the car new and it only has 15,000 miles, so I guess the vacuum hoses are drying out too.:wavey: :chevy: