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81 Corvette with CCC. I noticed my headlights started opening slower over the last few weeks and this past Friday night after a car show they initially did not open. I idled the car for a while and they finally opened. I did a system check with a mightyvac and found no issues with any of the valves, vacuum can, switches or relays. When testing the vacuum check valve ( per Willcox Instructions
) it would hold vacuum when testing the single port side and blocking the other two ports, but not holding vacuum when testing vacuum from one of the dual ports and blocking the second port on the same side. So I ordered a new vacuum check valve last night.
I also noticed over the last few weeks the engine started to have a rough idle, so I readjusted the carb and dialed in the dwell for the CCC last weekend. Could a bad check valve also cause a rough idle, other than issue with slow rising headlights?
A bad check valve can make it so your vacuum storage tank l will NOT hold vacuum and only rely on what the engine can produce for vacuum and make it so the headlight can take a while to raise up.
A bad check valve can make it so your vacuum storage tank l will NOT hold vacuum and only rely on what the engine can produce for vacuum and make it so the headlight can take a while to raise up.
I do much of the same thing on these Corvettes with all of the vacuum hoses. I remove the vacuum hose that works the headlights and interior HVAC system and take it out of the 'loop'.
IF the car does fine then I know I have a leak in the the system somewhere ...because when I reattach that removed vacuum hose and the engine begin to buck and act crazy...I know it has nothing to do with my tune-up.
Often times it is the actuator relays for the headlight due to they will leak vacuum when the engine is running and it is an easy test with a hose going to your ear and CAREFULLY listening at the bottom of the black square portion of the relay.
Obviously I have also inspected all other vacuum hoses adn connections adn make sure the EGR valve is good.
Dub do you think relay leak would show with a smoke test?
A waste of time and effort (in my opinion) when it is so easy to listen to. I can tell INSTANTLY if an actuator relay is leaking my using my tube on my stethoscope....or even a section of rubber hose going to my ear and putting the other end at the bottom of the relay like I mentioned. No need for high tech equipment here. You will spend more time setting it up and getting the machine to do its job. Just crank up the engine and listen.
I have never tried to use a smoke machine due to I have been checking these relays like I have for so long and I can have you drive up and I can tell you what is wrong in your headlight or wiper door vacuum in no time at all due to knowing how the system works.
Dub do you think relay leak would show with a smoke test?
A smoke test is not going to work as it is a vacuum system, not a pressurized system. Air is sucked in at any leak, not out so you would not see smoke. For a vacuum leak large enough to not only slow the system down but cause a rough idle it shouldn't be too hard to find.
Last edited by CanadaGrant; 09-18-2018 at 10:35 AM.
A smoke machine will work due to I use it on vacuum systems and EVAP systems and as long as the car is not running and you attach the smoke machine hose to the supply hose for the vacuum line...it will force smoke through under pressure and and a leak will show up...especially with UV dye in the smoke.
Well I received the new vacuum check valve today and installed. The headlights opened up, but when trying again they would not open. I did another system check of all vacuum components for the headlights, including the new vacuum check valve and this time found the drivers side headlight actuator would not build vacuum and open the headlight with the mightyvac. I was able to open up manually and check that the backside to close the headlight does hold vacuum and close the headlight. The passenger side works opening and closing. I also unhooked and blocked the hose for the driver side and the passenger side works normally every time.
So I guess it's off to locate a site that sells the actuator rebuild kit and do both sides at the same time.
DUB, I also used your testing method, disconnecting the heater source vacuum line. Afterwards I tested vacuum on that same line and the heater/AC controls hold vacuum when turned off, but not when selecting one of the functions such as VENT. Is the system supposed to hold vacuum in any selected function?
You could pull it and check it first. The passenger side on Dad's car had a small rust hole on the bottom. We epoxied it and everything now works fine.
DUB, I also used your testing method, disconnecting the heater source vacuum line. Afterwards I tested vacuum on that same line and the heater/AC controls hold vacuum when turned off, but not when selecting one of the functions such as VENT. Is the system supposed to hold vacuum in any selected function?
Thanks
Randy
Randy,
First off it is not that hard to service the seals on the actuator pod but just make sure you tape up the end of the threaded rod when you slide your new seal on it does not damage the critical area of THAT seal where it seals to the groove that MUST BE CLEAN on the shaft of the actuator.
The hood does not need to be removed to get the pod out. I have the hood closed when I am getting the pod out of the support and get it to lay on the bottom area. Then I raise the hood ALL THE WAY and I can get the pod out and reverse the procedure when I am putting it back it. So just having the hood up and supported by the hood support is NOT enough room for the pod to come out.
COUNT the number of turns on the eyelet clevis that is in the end of the shaft of the actuator also so it is back where it needs to be NO GUESSING. I usually position the actuator pod so the front tube for the hose is facing me and look at the number of threads and count them and put it back the same and it has never failed me.
As for using a hand vacuum pump. The vacuum should drop when you slide the control lever due to that vacuum is now going to a pod that has a much larger area so the vacuum now has somewhere to go. When I test the pods for the HVAC system I use my electric vacuum pump and run it and have the key on but the engine does not need to be running and move the lever and make sure the air is being diverted to all areas as designed. IF I am suspect on any pod I remove the rubber vacuum connector from the vacuum switch and manually test the hose going to the pod in question and see if it holds vacuum.
First off it is not that hard to service the seals on the actuator pod but just make sure you tape up the end of the threaded rod when you slide your new seal on it does not damage the critical area of THAT seal where it seals to the groove that MUST BE CLEAN on the shaft of the actuator.
The hood does not need to be removed to get the pod out. I have the hood closed when I am getting the pod out of the support and get it to lay on the bottom area. Then I raise the hood ALL THE WAY and I can get the pod out and reverse the procedure when I am putting it back it. So just having the hood up and supported by the hood support is NOT enough room for the pod to come out.
COUNT the number of turns on the eyelet clevis that is in the end of the shaft of the actuator also so it is back where it needs to be NO GUESSING. I usually position the actuator pod so the front tube for the hose is facing me and look at the number of threads and count them and put it back the same and it has never failed me.
As for using a hand vacuum pump. The vacuum should drop when you slide the control lever due to that vacuum is now going to a pod that has a much larger area so the vacuum now has somewhere to go. When I test the pods for the HVAC system I use my electric vacuum pump and run it and have the key on but the engine does not need to be running and move the lever and make sure the air is being diverted to all areas as designed. IF I am suspect on any pod I remove the rubber vacuum connector from the vacuum switch and manually test the hose going to the pod in question and see if it holds vacuum.
DUB
Thanks DUB. I ordered the parts and printed your detailed instructions. :-)
You can re-use the metal ring that is crimped on the pod in three places instead of buy a new one. You will see it when you remove the accordion tube seal BUT you really need to be careful when you are bending that tang back to 90 degrees so you can lift it up and slide the other two tangs that you DO NOT need to bend to remove that retaining ring.
TAKE a careful look on how the main vacuum seal is installed in the pod itself and how evenly it fits all the way around it in the housing. MAKE SURE that before you install the retaining ring.it looks the same way. Sometimes you may need to lift up on the seal and look to make sure it is caged as it is supposed to because that seal will not just fall into place.
ALSO...on the accordion tube seal...there should be a very small hole in that tube somewhere in the accordion area. Position that vent hole so it is at the BOTTOM of your pod when installed so it can not be on the top side and get water in it.
A bad check valve can make it so your vacuum storage tank l will NOT hold vacuum and only rely on what the engine can produce for vacuum and make it so the headlight can take a while to raise up.
DUB
sorry to interfere,Dub the relay worked ,high speed works great. Thanks again.
If I’m not mistaken can’t the pod be torn on inside requiring a whole new replacement?
YES...Not knowing which port on the pod is not holding vacuum is what is missing here.
IF the tube on the pod that faces the radiator will not hold vacuum the pod is BAD due to the internal seal is torn.
IF the tube on the pod that faces the front of the car will not hold vacuum then the seals at the shaft can be serviced.
No need or vacuum pump to check this . It can be simply done by hand. Remove the two hoses from the actuator relay and open the headlight door half way. While holding gn the door...take your thumb and cover one of the hoses and see if you have resistance when you move the door up or down. While l pushing down a bit. Let off on your thumb and if you fell the air coming out...that side of the pod is GOOD. The do the other hose the same way.
IF the headlight door goes up and down easily and you can hear air whooshing when you have a hose capped off with your thumb.....that side of the pod is what is bad.
Well it definitely was a bad seal on the drivers side. I ordered the parts locally in Florida from Ecklers. They arrived the next day and I am about to install. I did notice the new Actuator Rod Seal are a little different from the originals. On the originals there looks to be an o-ring molded into the rubber on the narrow end. On the new seals there appears to be none? I called Ecklers technical support and they said these are the correct seals for 68-82 C3 Corvettes and they guarantee they will work. I attached a few pictures below. Has anyone else ordered from Ecklers or had this experience with the difference in the seals? I just don't want to go thru installing and having issues afterwards.
Thanks
I have used those same seals. They are a snug fit on the rod and with negative (vacuum) pressure in the can it makes it even tighter. The ones in my wife's 78 have been in use for over 12 years and are still like new.
09-16-2018, 01:25 PM
Slow opening headlights / Rough idle related?
