So my headlights on my 79 had been working ok. The drivers side always came right up and the passenger side was a bit lazy but always came up. Yesterday suddenly the drivers side comes halfway and the passengers side doesn’t come up at all. If I manually lift the the passengers that makes the drivers side come up completely on its own. Switching the light switch off makes them then go down normally. I check all th vacuum hoses from the manifold back to the two actuators, the two relays, and to the reservoir tank just to make sure À hose hadn’t come loose/off etc. I can’t check vacuum because I don’t currently have a vacuum gun/gauge. I then looked to inspect the actuator seal and discovered the passenger side actuator seal is visibly torn on the outside and the dust boot is basically bunched up towards the rod pin. If I I manually articulate the headlight partially up and down in a pumping motion I can definitely hear a suction/air leak noise. Doing the same to the drivers side headlight I don’t hear a suction/air leak noise (that seal and boot look good from the outside). I’m pretty sure I’ll need to pull off the actuator pot and replace that seal. Would a bad seal on one light cause both lights to not function? And while I’m replacing that seal should I bother to replace everything from the manifold back with one of those complete vacuum replacement kits that come with all the precut lines, filters, relays etc? Thanks

 

You need this actuator seal kit:



Shorten each hose a half an inch to make sure you have a good connection.

Teat the rest of the parts before you order anything.
http://www.corvette-101.com/vacuum.htm

 

Thanks that’s a nice troubleshooting guide. You think I should start with replacing this seal then see how the rest of the vacuum system is functioning before replacing anything else, if needed? I’ll probably replace the other seal while I’m at it