Is this Normal?
Thread Starter
Instructor
Joined: Jan 2013
Posts: 122
Likes: 0
From: Phoenix Arizona
Is this Normal?
Trouble shooting my 69 vacuum system. The wiper door opens about 10 sec. after the motor starts then closes. The head lights operate correctly. I read the threads about this problem and been checking all the vacuum tubes and making sure there tight.
Also new check valve, and filter. And rebuilt the wiper door relay.
Also I noticed about 15 sec. after shutting off the motor I hear the wiper door head light relay located at the driver side engine compartment dump air. Is this normal ?or do I have a problem with it.
Also what vacuum pressure would be considered normal?
Any suggestions would be helpful
Thanks! the Captain
Also new check valve, and filter. And rebuilt the wiper door relay.
Also I noticed about 15 sec. after shutting off the motor I hear the wiper door head light relay located at the driver side engine compartment dump air. Is this normal ?or do I have a problem with it.
Also what vacuum pressure would be considered normal?
Any suggestions would be helpful
Thanks! the Captain
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,114
From: Crossville TN
Either the seal is going bad in the wiper arm safety valve and/or the metal vacuum transfer tubing (runs across the firewall, just below the wiper motor) is getting clogged up. Remove the hoses at both ends of the transfer tube and blow compressed air through it. There's no fix for the bad safety valve, except to replace it.....again, and again, and.... 
Thread Starter
Instructor
Joined: Jan 2013
Posts: 122
Likes: 0
From: Phoenix Arizona
I have a new in line filter installed, but I will look and check the metal tubing on the firewall and the wiper saftey valve.
Thanks for the info! I will follow up with what I find.
Tha Cap
Thanks for the info! I will follow up with what I find.
Tha Cap
Team Owner
Joined: Sep 2006
Posts: 31,172
Likes: 4,250
From: Westminster Maryland
Hi C,
Often when the wipers or headlights open briefly on their own at start up and then close on their own it's because of a leak in the 'control' side of the vacuum system.
The system was designed with small hoses for the 'control' side of the system and large hoses on the 'servo' side of the system. That's so on start up the 'control' side of the system needs less vacuum to operate than the 'servo' side. This way even if there's no vacuum left in the system the doors stay where they are on start up because the relays receive full vacuum before the actuators.
If there's a leak in the 'control' side IT takes longer to receive full vacuum than the 'servo' side, so the doors open; then, the 'control' relays catch up and the doors close on their own.
So, perhaps checking for leaks in the relays and switches, and their hoses, may help.
Good Luck!
Regards,
Alan
Often when the wipers or headlights open briefly on their own at start up and then close on their own it's because of a leak in the 'control' side of the vacuum system.
The system was designed with small hoses for the 'control' side of the system and large hoses on the 'servo' side of the system. That's so on start up the 'control' side of the system needs less vacuum to operate than the 'servo' side. This way even if there's no vacuum left in the system the doors stay where they are on start up because the relays receive full vacuum before the actuators.
If there's a leak in the 'control' side IT takes longer to receive full vacuum than the 'servo' side, so the doors open; then, the 'control' relays catch up and the doors close on their own.
So, perhaps checking for leaks in the relays and switches, and their hoses, may help.
Good Luck!
Regards,
Alan
