72ray

72ray
Casual User
Aug 7, 2018
80
68
Sydney Australia
VetteCoins
2,061
Car
1972 coupe 350 TH400
Never had a problem before now but the wiper door decided to not move up when selected last week. I left the override switch open to see if anything changed and up it popped after 10 minutes if highway driving. Great! Arrived at my destination and selected normal mode, down went the wiper door, happy days. But no, yesterday I selected the headlights and up pops the left side but no right side. I cycle the light switch. Left responds appropriately but selected on and same again. Left side up only. So I cycled the switch again and a mate gently encouraged the right side light unit with a finger nail grip and yay! Up it popped.... and up it has stayed 🤦🏻‍♂️
My wiper door remains motionless btw.
Any learned thoughts?
 
Never had a problem before now but the wiper door decided to not move up when selected last week. I left the override switch open to see if anything changed and up it popped after 10 minutes if highway driving. Great! Arrived at my destination and selected normal mode, down went the wiper door, happy days. But no, yesterday I selected the headlights and up pops the left side but no right side. I cycle the light switch. Left responds appropriately but selected on and same again. Left side up only. So I cycled the switch again and a mate gently encouraged the right side light unit with a finger nail grip and yay! Up it popped.... and up it has stayed 🤦🏻‍♂️
My wiper door remains motionless btw.
Any learned thoughts?

I’ve traced and checked the vacuum hose from the inlet manifold, through the filter, past the dual vac. Value and the local easily visualised joints. Nothing found.
 
If all your vacuum lines are original to the car, it is highly likely you have one or more vacuum leaks. This car has an amazing amount of vacuum lines, so chance of a leak is high. I highly suggest you get a good vacuum gauge and a hand vacuum pump. I would start your troubleshooting at the intake vacuum output fitting and move on to tank area and go from there on. Get yourself a schematic of the lines and familiarize yourself with all the vacuum relays, switches, check valves and accessories. Common failure points are at relays, switches and under the dash switches, heater and ac controls and t's.

I replaced all my lines and clamps when I restored mine. I had a defective wiper park vacuum switch and a leaking vacuum switch behind the tachometer. Also had several lines that had swelled and were leaking where they plugged into relays and such. After a full restoration of both headlamp and wiper door mechanisms, everything works well as it should. The headlamp doors open and close quickly and both together now, and the wiper door opens and closes smoothly as well. I must admit that this was a large project to undertake, but the final results were well worth it. Best of luck.
 
I saw a guy blowing cigar smoke through a system once in order to see where leaks appeared. I don’t smoke and I’m wondering if there’s another way of doing something similar
 
I saw a guy blowing cigar smoke through a system once in order to see where leaks appeared. I don’t smoke and I’m wondering if there’s another way of doing something similar

It's been a long time but in our muscle car years we use to use a propane torch to find vacuum leaks. Start the car. Let it warm up. Turn on the propane about 1/4 or more open, don't light it (likely unnecessary instruction...lol) and trace your vacuum lines start to finish. You will hear an unmistakable change in the engine sound if and when it sucks the extra fuel into the intake through a leak.
There are obviously more sophisticated methods now but this worked for us.
 
So then.... this week I replaced the in-line filter in the vacuum hose the near the inlet manifold (as I could see no filter screen in it when I looked through it towards the sky) and also the one into two check valve just up from the filter. At the same time I replaced the shaft seal on the wiper door actuator and fitted the (up until now missing) dustcover/boot that protects the shaft and seal. All seems to be working well. Only thing I see (?) wrong is the wiper door 'self' actuates one cycle up and down from time to time and also the left headlight comes up before the right. not sure if that's normal?
 
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