Are Vacuum actuators supposed to hold vacuum or leak down?

[graybo]

I just got new vacuum actuators for my superbird from classic industries.  One had a ripped boot as soon as i opened it and the other I installed.  When I apply vacuum to it, the door opens and stays open as long as I keep pumping vacuum to it.  As soon as I shut the vacuum off, it slowly bleeds down and closes.  Are these supposed to hold vacuum without a constant vacuum source?  Thanks

[70 sublime]

I thought the Daytona and Superbird head light doors had a spring that keeps them open and the vacuum is what keeps them shut ?
That is why when you see pictures of dead cars the lights are open ?

Still sounds like they should not leak open or closed

[graybo]

I thought the Daytona and Superbird head light doors had a spring that keeps them open and the vacuum is what keeps them shut ?
That is why when you see pictures of dead cars the lights are open ?

Still sounds like they should not leak open or closed

You are correct.  I have the springs but I didn't attach them to the L bracket yet.  I'm in the testing phase.  I'm with you I don't think they should bleed down.  But I'm hoping I'm wrong, cause that will mean I have 4 vacuum actuators that need rebuilt.   

[Mopar John]

John,
With plenty of experience with these vacuum actuators and headlight doors I will chime in.
Yes! You need vacuum to hold the headlight doors down!
If not the safety springs will make them pop up!
It is a national meet past time to walk around and see who's head lights pop up the quickest.
The cure is not easy.
You have to include the storage canister, the hoses, the switch, the connectors and the actuators!
On my cars I have installed the pop up springs about a 1/2 wind less to reduce the resistance on doors!
You might not even have an actuator problem to begin with check every thing.
MJ

[birdsandbees]

Mine are original, other than I took the springs off, and have never been rebuilt. The springs are to hold them up and not bobbing on bumps and yes if you have leaks they will go "frog eyes" after shut down. That said, the pods should hold vacuum both up and down and not leak down.

[DAY CLONA]

I just got new vacuum actuators for my superbird from classic industries.  One had a ripped boot as soon as i opened it and the other I installed.  When I apply vacuum to it, the door opens and stays open as long as I keep pumping vacuum to it.  As soon as I shut the vacuum off, it slowly bleeds down and closes.  Are these supposed to hold vacuum without a constant vacuum source?  Thanks

Your just applying vacuum directly to pod with what I assume is a mityvac (hand pump) assuming the pump has a check valve to hold vacuum after pumping, the pod under vacuum should hold the door up (install a valve or pinch off the line if you suspect the pump)...

When I'm buying pods, new/used/NOS or repro for customers projects, I test the pod by pulling the rod far forward (extended) then block off the rear pod vacuum port with my finger, and try to push the rod back (retracted) if the rod can be pushed back all the way with the rear port blocked/plugged and stay there, then the diaphram is junk.... I haven't seen a repro pod yet that works as intended, be cautious of some vendors offering "repairs" as all they do is inject a liquid membrane into the ports to try and seal the diaphram that may/may not work, or fail shortly down the road... invest in some good pods, used/NOS (always test them regardless) because they suck to change out after the nose is hung...


FYI, I generally prefer the 69 pods, as they have a smaller diameter magnet attached to the internal diaphram, the 68 pods have a much larger diameter magnet internally, the intention of the magnet for the STOCK Charger hidden door system was an assist to hold the hidden door up in low vacuum situations, when the same pod is applied in a Tona/SB application the magnet is now contacted in the closed door position, while one might think the 68 pod would be ideal for keeping the door closed because of it's larger magnet, it bites you when you need the door to open and you have low manifold vacuum, or leaks in the system/lines/switch/etc and can't overcome the magnetic pull... personally I don't recommend the "safety springs" attached, you may see them as a helper in lifting the door, but that was not their intention... a good switch. new lines, new vac resv. canister, and 2 good pods should yield a foolproof system, regardless of the parts new or used, they need to be all vacuum tested, ......untested/unproven is one weak link you don't need, as you'll be chasing ghosts in the system...


Mike

[Sgt Superbird]

I'm just story telling now, but my vacuum system is pretty "air tight". There was an issue with the switch, that the previous owner took care of. My buckets stay in the closed position for weeks (months?) BUT, if I shut either door or trunk, one bucket pops up half way. I've learned to open the wing vent before closing my door, and the bucket stays closed! Finicky system, for sure.

[XH29N0G]

I have a question about these (and do not know how they are designed) but I work with vacuum and there is always some leak, but many things can be very leak proof and from what I read here it seems that is the case with these.

My question is whether there are simple ways to test.  If air leaks in, it will also leak out.  Is there a way slightly pressurize so a soap bubble test could be done?  Then you could decide how to reduce the vacuum leaks. 

Ignore if this is a stupid question.   

[DoubleDlover]

So that one way check valve on your vacuum canister has a lot to do with the system. If its bad you will ALWAYS have this problem. Its design is to keep vacuum in the tank after you turn the car off. Keeping vacuum to pull on the doors and give you at lest one working open and close cycle. If there is a leak at any of the hose fittings and nipples. diafram in the pod. and such that will do you in as well. But say everything is air tight like a frogs ass. If that check valve is bad like i said your done. One nipple on the tank air can go in and out both ways. The other nipple you can blow air in but if you try to suck air out on that nipple it should stop you from being able to do that. If it doesnt your screwed....

[DAY CLONA]

So that one way check valve on your vacuum canister has a lot to do with the system. If its bad you will ALWAYS have this problem. Its design is to keep vacuum in the tank after you turn the car off. Keeping vacuum to pull on the doors and give you at lest one working open and close cycle. If there is a leak at any of the hose fittings and nipples. diafram in the pod. and such that will do you in as well. But say everything is air tight like a frogs ass. If that check valve is bad like i said your done. One nipple on the tank air can go in and out both ways. The other nipple you can blow air in but if you try to suck air out on that nipple it should stop you from being able to do that. If it doesnt your screwed....

Agreed, a lot of guys will use a 50 yr old can thinking it looks good, but if the check valve is bad regardless of the can's outer integrity, nothing but a ghost chase will ensue.... understanding the function and how it retains vacuum is fundamental to building a good working system

The dash switch is another culprit, and often misunderstood in it's function/operation


Mike

[graybo]

Okay sooooo.  I think we are getting a little off my original question, which was...  Are the Vacuum actuators supposed to hold air tight in the up (or out) position?  Or are they made to have a small leak?  I know that they are air tight in the down(or IN) position.   I am starting at the nose first then I'll walk my way back the vacuum line and finally to the switch. 

[graybo]

Okay sooooo.  I think we are getting a little off my original question, which was...  Are the Vacuum actuators supposed to hold air tight in the up (or out) position?  Or are they made to have a small leak?  I know that they are air tight in the down(or IN) position.   I am starting at the nose first then I'll walk my way back the vacuum line and finally to the switch. 

Disregard.  DAYCLONA answered this very detailed. 

[birdsandbees]

As did I... it would be pointless if they leaked.

[graybo]

As did I... it would be pointless if they leaked.

Yes you did. Much appreciated and nice pics

[DoubleDlover]

Hi there. Well im glad the others were able to help you out. r

[graybo]

Hi there. Well im glad the others were able to help you out. r

I read your reply also.  Very informative.  Thank you DOUBLE D LOVER!   I am a little slow on responses because of work...But much appreciated.  Graybo

[DoubleDlover]

graybo  good luck with everything. But like day said. that switch isnt 100% air tight. So at some point in time it will loose vacuum. But i beleave now you know more about that system then the fricking super engineers that came up with it. LOL

[wingcarenvy]

This is not really answering the original question but I thought I'd offer a little tip for those reading that are chasing a leak. Back when I was a tech for an auto dealer I used a smoke machine to inject smoke into the system at one of the lines. Then wait and the smoke will exit at the leaking point. You can buy these smoke machines cheap online.