Alwyn678

Sometimes they lock into place and eventually will close. What causes I and how do I stop the problem?


Thanks

SwampeastMike

Do you mean that they close by themselves when locked up?

Chinaski

I'd start by checking all of the vacuum lines, the ones under the hood to the actuators/relays are all easily accessible.

I just replaced all of my relays and actuators with all the lines, mine work perfectly now.

7T1vette

To test the system, do the following:

Engine idling; remove both hoses on the vacuum actuator for the headlamps (mark which is which); remove the center hose on the vacuum relay for the headlamps; connect the relay hose to one fitting on the actuator can...if nothing happens move it to the other fitting; If it opens FAST, there is nothing wrong with the actuator or the headlamp bucket system; if it moves slowly, the actuator MAY be leaking internally AND/OR the headlamp bucket system may need lubrication (white lithium grease from tube on pivots); move line to the other fitting to verify action in other direction.

If the bucket/actuator works as it should, you need to replace the vacuum relay (or relays) for your headlamps. There is no simple 'repair' for these; and the replacements are not the best quality item. But that's the only available fix.

SwampeastMike

Regarding vacuum motor and vacuum relay repair:

If a headlight vacuum motor holds vacuum indefinitely at the rear inlet but leakes from the front, the problem is with the seal around the shaft. Shaft seal leaks are the most common and repair kits are available that will create lasting repairs. A leak from the rear inlet means that the main diaphragm has a hole and there is no reasonable way to repair. At least one vendor still sells OEM actuators for one side (left I believe) but they are no longer made and will soon run out. One OEM unit will cost more than two aftermarket unit but is still a good value as it will likely last for a LONG time. When it comes to the aftermarket vacuum motors consider yourself lucky it holds vacuum indefinitely (on BOTH sides and at least overnight) upon arrival. Test BEFORE installation with a hand vacuum pump!!!! Consider yourself very lucky if it passes a number of such tests before installation. Consider yourself extremely lucky if, after installation, it lasts for more than a year or two holding vacuum indefinitely.

From what I read here at Corvette Forum, the relays CAN often be repaired. Such is often nothing more than disassembly and lubrication (with silicon grease) of the internal plunger. Search for instructions. If you don't want to DIY at least one forum members repairs relays. The OEM relays are not available either and from what I read here the quality of the aftermarkets is as bad--maybe even worse--than the vacuum motors!

Dave J

I've been rebuilding original relays for years. Haven't had one come back yet.

Indeed. Replacement of the internal piston with a machined version is what I do. I've found simply lubricating the piston is only a short term fix, as most of the old pistons have shrunk to such poor tolerances not much will revive them.

To the OP. There is a wealth of knowledge here on the forum explaining how to test the system for vacuum leaks. I could go into great length on how to do it, but I'm late for the last home hockey game for my team. Maybe someone else could direct you, or even chime in. I have quite a pile of responses in my posts if you want to check out my posting history. I can step you through it tomorrow.

Bottom line, most problems are due to;

1 - original leaky vacuum relays
2 - leaky seal on the front of the headlight actuator
3 - original hoses leaking at the union between hose and component
(cut off the last 1/2 inch of hose)

7T1vette

I've attempted the repair of the vacuum relays and it's not as simple as you make it sound. There are seals on the shuttle valve that are usually hard, loose (causing the problems) and can't be reused. There are no "replacement" seals available, and you basically need to re-engineer the shuttle valves. There are difficulties in disassembling them and reassembling them. The trouble is not worth the effort, IMO.

If the test I described above shows the actuators to be fine (which is my suspicion), you don't need to use info in the above post to "repair" the actuators. If not, then utilize the info in the above post to repair them.

Peterbuilt

Here's how to check all the vacuum components.

http://www.corvette-101.com/vacuum.htm

Then make sure that the springs are in place and that everything moves freely.

Alwyn678

Wow,

Amazing amount of knowledge here. I really appreciate the help. I think I will start w/the lithium grease.

Where/What are the most important places to lube?


Thanx

7T1vette

Simpler to start with the "actuator bypass" test, but...

As I stated in my post, lubricate the pivots....moving parts linked together.