headlight actuator issue
Thread Starter
Intermediate
Joined: Aug 2014
Posts: 39
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headlight actuator issue
Hi
I have taken out my headlight actuator to check it because my lights don't open at the same time. I thought it was the rod seal, but when I hook up a vacuum pump to either inlet of the actuator, I noticed that it won't hold a vacuum. You can pump it about 20-30 Times and the rod will move slowly in or out, but I am wondering if there is a leak in the diaphragm if it won't hold a vacuum when booking up a pump to either side? Thoughts?
I have taken out my headlight actuator to check it because my lights don't open at the same time. I thought it was the rod seal, but when I hook up a vacuum pump to either inlet of the actuator, I noticed that it won't hold a vacuum. You can pump it about 20-30 Times and the rod will move slowly in or out, but I am wondering if there is a leak in the diaphragm if it won't hold a vacuum when booking up a pump to either side? Thoughts?
Pro
Joined: Mar 2007
Posts: 727
Likes: 113
From: Austin TX area
Make a small investment in hand held vacuum pump and get troubleshooting guide from dr.r or Wilcox etc. you can than check the entire system out and determine where the issues are? As put the year, there are some differences between the years.
Le Mans Master
Joined: Aug 2006
Posts: 7,426
Likes: 1,559
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
If you block off the front (straight) port and can still pull the rod out (or in actually, with some drag) then the shaft seal is leaking.
If you block the rear port (90 deg one) and the shaft can be moved (either way) it's the diaphragm.
Shaft seal is an easy fix
https://www.corvetteforum.com/forums...new-seals.html
Replacing the diaphragm is not really practical, new unit time
M
If you block the rear port (90 deg one) and the shaft can be moved (either way) it's the diaphragm.
Shaft seal is an easy fix
https://www.corvetteforum.com/forums...new-seals.html
Replacing the diaphragm is not really practical, new unit time
M
Thread Starter
Intermediate
Joined: Aug 2014
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Thanks for all the replies. Well the rod doesn't move if I plug either port so apparently the seals and diaphragm are fine. Guess I will have to keep troubleshooting the rest of the system to figure out why the right headlight opens slower than the left
Team Owner
Joined: Sep 2006
Posts: 31,267
Likes: 4,362
From: Westminster Maryland
Hi mrc,
Does a 76 have 1 or 2 relays?
If 2, you can reverse the hoses to the actuators and IF the symptoms move to the other headlight you'll know it's the relay… if not it's the actuator.
Regards,
Alan
Does a 76 have 1 or 2 relays?
If 2, you can reverse the hoses to the actuators and IF the symptoms move to the other headlight you'll know it's the relay… if not it's the actuator.
Regards,
Alan
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