Air grabber will not open...help

(disclaimer it's a Ramcharger but there's a lot more air grabber hoods out there)
OK hood worked ok then switch went bad, I replaced it and it isn't working and it just ain't makin' sense to me. Now before we say "well it's obviously the switch" I'm getting the same vacuum going in as coming out, so I'm stumped

1) Right off the manifold at Idle 18lbs of VAC, if I hook the manifold hose directly to the "open side of the door actuator, it opens right up normally



2) After going through the can, switch, all the hoses and back to the actuator it drops 17lbs and will not open the door, rev it up to 20 lbs and nope still doesn't open


Now I know the basic physics that the hose off the manifold is a big bigger so I have some more volume, but why wouldn't it would the way it's supposed to with the factory hoses???

bypass the solenoid that's what I had to do with mine..

Is the door binding maybe some lube on the pivot points.

Thanks guys! (this is actually the 1st time here on moparts anyone has ever answered one of my questions!)

FC7 - I've done that, I've also disconnected the hose plug from the switch and jumped directly from the input suction line to the door open line...same

71GTX - Good suggestion but everything is pretty new/lubed. if I "help" the door linkage up a bit it will eventually catch and open. But again if I use the manifold suction it opens right up

also checked for and kinks/pinches in the hose routing. I do have two plastic "splices" where I burned one of the hoses otherwise the hose harness is new

during the assembly...


and it did work fine once
[img]http://i129.photobucket.com/albums/...ae8bw.mp4[/img]

If it helps

- Hose kit is new reproduction, made 2 repairs due to heat damage (my goof, it laid on exhaust manifold) cut and used little plastic splices

- Actuator a '70 date code used original (I had 3 "New" ones, all went bad after a few uses)

- Switch is a repro, actually the second, the 1st "New" switch went bad after a few cycles, leaked internally , you could hear it. this is a replacement from the vendor, it's holding pressure

Just for giggles, have you tried swapping the 2 lines on the vacuum reserve canister? one port has a 1 way check valve in it, you didn't put any compressed air to the reserve canister did you?

Is the reserve canister repro/NOS/used?

If you have a stethoscope, check for leaking vacuum at the switch body (broken nipple??) or from the line going from the switch to the vacuum check valve. You are loosing vacuum before it is getting to the door actuator.

or try switching the lines on the pod that opens the hood. i had to do that on my car to get it to work.

Thanks everyone!
- Tried swapping line on canister...same result. It's a new repo
--Compressed air? should I have to do that?
- Don't have a stethoscope but don't hear any leaks. when the last switch went bad you could hear it under the dash. But I'll go get one
- swapped line around, same. with the door "closed" if I help it up a bit it opens but will not work by itself

I appreciate everyone's time!

If you can't hear it inside the car, it means you're loosing vacuum in the engine bay. A stethoscope is a nice tool to have when you need to work around a noisy engine.Investigate your vacuum source to see if the tubing is loose at where it is pushed in. If you are coming off the manifold check your 1/8" line to make sure it is snug and the rubber flexible and soft. If you're coming of the carb throttle plate, check your connection there. If the tubing slips off with no hassle at all, your leak is there. If your canister is a new repo, was it working before with your old canister? If yes, suspect the canister or the connection to it.

"Compressed air"...I asked that in case you hit the reserve can with it, because it will destroy the check valve in the can, it sounds like you have little to no vacuum going to the switch? the repro canister, if it's from Charger Specialties they've had issues with the check valves retaining a reserve inside the can

Ah! gotcha...no haven't molested the can in anyway. I got it from PG classic I think?

I've got 18lbs going in the can, 18lbs coming out of the can and 17lbs terminating at the actuator..I can rev it and get 20+ so I'm getting suction through the switch, it seems to be a volume issue

I'm not sure. If you've got 17 inches of vacuum going to the actuator, the actuator should open. If nothing is binding with the mechanisms in your air box, I'd be looking at your actuator next. Put your vacuum pump directly on the actuator inlet and see if it opens the A/G door.

Do you have a return spring on the actuator lever? If so I'd remove it and see what happens. I had the same situation as you, door wouldn't open. Plenty of vacuum, no leaks. I removed the spring and it operates normally. Closes just fine too.

A process of elimination helps by eliminating each component, granted you switched the lines on the canister. but if the internal check valve is ruptured the can will still draw vacuum but not "store" it for when it's needed for like the draw required to initially open the door, put a splice/connector between the 2 reserve canister lines to join them, bypass the reserve canister and see if the door activates? go down the line eliminating systems, switches, connections. etc

Thanks guys
- L.R. that would make sense but if you put the vacuum like from the manifold to the actuator it works fine, so that's not it (and I have good experience with bad actuators, I had to go though 3 "new" ones before I bought a 47 y/o original one that worked!!

-469 runner I did, but just went out, popped the spring off to see if that made a difference...nope, still sits there

- Dayclona bypassed the canister, same results

- Sure seems like the switch is the issue, but just for fun I again popped the line block off the back of the switch and ran a hose directly from suction (green) to the open (yellow)...completely bypassing the switch and electric bleed port, nothing.

- OK I'm ready for the crude comments to follow but I thought "maybe there's a restriction or "junk" in the hoses causing a flow problem? so I sucked on each one and all are clear

does anyone know how much suction at the actuator you're supposed to have??

Hook up a Tee with a vacuum gauge going to your reserve canister if you can. Try using one side of your repair splice if that's in a convenient location. Switch on and let the engine generate your vacuum until you reach 18 inches at the canister. Switch off and read your residual vacuum or better still, the rate at which you're loosing vacuum. If vacuum holds, that door should open. Either your can or the check valve and lines going to it are loosing vacuum or your switch is reversed ie open is closed and closed is open. Yes, that can happen........you did say it was a repro switch.

Hi Guys...I always like to say what fixed problems, it's been a while but here's the story...the after market "NEW" parts are #$%^ so I made it electrically controlled.
- Eliminated Trouble prone Vac Switch
- Replaced with a R/W defogger switch looks identical and fits in dash the same
- Moved the elect. vacuum solenoid to the engine bay. I cut the bottom of the accumulator canister and "hid" it in there
- So now Full vacuum goes to switch when I turn it on it ports vac to the "door open" side when I turn it off the original return string is more than adequate to close the door...works great should have did this to begin with!

pretty ingenious repair.
good job, and thanks for reporting back.