69 RS Headlamps

[timhahn]

I need some help with my system. My headlight system for my 69 camaro has been completely replaced including the headlight swith, vacuum relay, all vacuum lines, bushings, check valves, etc. The only two items I have not replaced are the the large vacuum cannister and the two actuators. Is there an easy way to test the actuators before I actually break down and buy new ones? If so what is this. I started the engine and ran it for a good ten minutes but the doors never did anything. Should I wait longer until I know the cannisters are good and evacuated. This vehicle did not run and sat in a backyard for 7 years.

Second thing, and I don't know if this affects the performance, is I installed an aftermarket high rise Edelbrock Manifold with a Holley 650 double pump, double feed carburetor. I had to use a port off of the top back of the carburetor since the manifold hole is under the secondary pump. Could this also be one of my problems? I checked the vacuum, by hand and not by gage, the suction appears to be fairly strong coming into the vacuum relay. What should I expect if I hook up a gauge to this hose with respect to the vacuum reading?

This vehicle has a big beefy engine and cam. Can this cause problems with this system and is there a remedy to the problem? Any help at all would be appreciated as I am down to the last few things on my headlights.

[RamAirDave]

Troubleshooting hideways is very similar to electrical issues.  Start at the front of the system to see if you have vacuum at the actuators, both red and green hoses in the respective on/off positions of the switch.  If not, work your way back to find where it's being lost.  If you're not getting vac to the actuators, check that you're getting vac into the valve on the can from the switch.  If not, check that vac is getting to the switch from the engine, and so on.

It shouldn't take but a few seconds to get the system vacuumized (is that even a word?).  If pulling very low vacuum at idle, give it some RPMs.

You can check the actuators by pulling a vacuum on them.  It should move the rod (test both directions) without any leakdown.  There's a pretty decent chance they've gone bad.  If you think the large vac can is possibly bad, you can disable it from the system to eliminate that as a possibility.  It's only used to hold reserve vacuum for when the engine is turned off, but can be a source of a vacuum leak.

Also, Ive had a brand new, out of the box OER RS headlight switch that was bad.  Ive also seen OER valves (one that mounts on the reserve can) that were made backwards internally.  R hose to R terminal and G to G, they would close when the lights were turned on and vice-versa.

[rich69rs]

I have also observed the problem that RamAirDave mentions with regard to OER pieces being backward from the originals.  Two years ago, when I did the front end restoration on my '69 RS Coupe (327 base engine), I changed out the vacuum cannisters (actuators), not because my originals were bad but because I thought it made sense at the time.  Plumbing the vacuum lines to the new cannisters as per the attached or as per the original cannisters resulted in the doors working backward, i.e. open with light switch closed, closed with light switch pulled to open.  I reversed the vacuum line connections at the cannisters to make the lights work properly.  By reversing the plumbing there, it can't be seen when looking into the engine compartment.  You could accomplish the same thing by swapping the connections on the relay valve, but then you can see that.

My experience has been that if you have adequate vacuum (stock setup) and everything is working properly, doors should work within a few seconds of the engine starting. 

Attached are a couple of pretty good trouble shooting aids. 



Good liuck.

 Richard

[Dave69x33]

I tested my 69 actuators by using a long hose connected direct to the vacuum fitting on the intake manifold.  I draped the hose over the outside of the fender and connected the opposite end directly to each side of the actuator.  With the engine idling, each actuator worked great - relatively quick and smooth.  That told me the vacuum leak(s) were else where in the system.

To test my vacuum reserve canister, I pulled it from the car, and tested the vacuum leak-down rate to determine if it leaked.  I used a MightyVac hand actuated vacuum pump to test the canister (used to bleed automotive brake systems, etc.).  It held vacuum.

I have noticed that the repro hoses are stiffer that the originals.  If they get hard with age, they loose an air tight seal on the various fittings.  I tried to use a small amount of sealant which helped some.  Both doors still do not open unless I help them along about half away and then they work the rest of the way.  The doors are not hanging up so the vacuum is not strong enough to overcome the “over center” spring.

Good luck with yours.

[rich69rs]

Be sure the check valve is good and is not leaking.  About a year ago, I had to change mine.  The doors were not opening smoothly due to lower than normal vacuum.  Changed it and all was good.  Readily available as an OER part in the aftermarket.

[JohnZ]

Although the RS vacuum system is complex, it's child's play compared to the vacuum systems on '68-up Corvettes; one of the most common sources of inadequate vacuum and slow actuator operation on Corvettes is failure to change the plastic filter - it was a maintenance item that was supposed to be replaced periodically, but never was. The RS system has the same white plastic filter, in the vacuum hose from the intake manifold; remove it and hold it up to the light and look through it - if you can't see through it, it's plugged - clean it or replace it.

[timhahn]

Thank you everyone for the help. My actuators were frozen solid and would not move. Looks as though they have not worked in years. This is a great forum which has really helped me out. I look forward to being one of those that gets to share information in the future.

[click]

squirt some WD40 in the vac holes to see if it loosens up the rubber boots inside before you toss them out. If you do toss them, the new ones from Ricks work great.