woodeye47

This all started with getting the vacuum truck latch to work. I am getting 18" of vacuum off the carb but only 4" at the valve at glove box and that is not enough to pull trunk latch. I started tracking an ran a hose direct to vacuum tank on the firewall that feeds the valve in glove box and it operates the trunk latch very nicely. So I Tee into the line coming off carb going to power break booster and again only 4". My Brake booster is a Moraine unit with the Tee on top. One side is fed from carb and other side continues onto the Vacuum canister under fender. I get 18"' on hose that goes into booster, reconnect hose to booster and test at other side of Tee and get 1/2" top. Any help where I am loosing the vacuum will be much appreciated. I am out of ideas as to what it could be.

Supernice88

Was the car running alright before you started looking for this leak? If so check under the dash board and listen for any of the hoses leaking from the vent/heat hoses. Check the hoses coming off the carb for splitting where they connect.

woodeye47

The car runs quiet well actually. I will look and listen under dash as suggested. I just cant figure out how I can get 18" from the line going to the Tee on the Brake booster, then reattach and pull hose going from booster to Brake Vacuum booster and pulling 2" max. Frustrating for sure. Thank you for your sughgestions

Supernice88

I'm not understanding where you're disconnecting and then connecting. "I started tracking an ran a hose direct to vacuum tank on the firewall that feeds the valve in glove box" where did you get this vac line from to put in place of the original one?
"I can get 18" from the line going to the Tee on the Brake booster, then reattach and pull hose going from booster to Brake Vacuum booster and pulling 2" max" Can you clarify this to make sense? Are you talking about the other side of the tee to the storage tank? I would have to go and test my car and see if what you are getting for readings are normal functions. Can someone jump in here and correct me if I'm wrong - the storage tank is there for backup vacuum to the brake booster in case the car stalls, so if the tank is already full or near it you would get a zero reading between the booster and the tank. Same thing on the trunk release storage tank, there's a small amount of vacuum stored to release the trunk after the car is shut off. When you pull the **** for the trunk release are you doing it with the car running or off?
I had asked if the car is running ok because if you had some kind of vacuum leak it would be running rough.

no1oldsfan

Vacuum lines scare me. I passed on 60 Cadillac that was loaded with everything. Power this power that. I opened that driver's door and saw I swear hundreds of vacuum lines. I said to myself. Oh hell no. Your problem should be simple. Track those lines down. Make sure everything is tight on all ends. Soapy water can be your friend on these.

woodeye47

Supernice88 thank you for trying to help me sort through my issues. I used the line that was already in place to the storage canister on the firewall. It has two lines running from it, one to the trunk latch and one to the glove box located trunk release valve. When I first put my Vacuum gauge on this line coming from a brass Tee ( the other line running from this Tee goes direct to the Vacuum Brake Booster) at back of carb and with engine running I showed 4" of vacuum. This is not enough vacuum to pull trunk latch far enough to release. Next I pulled the line going into the Brake Booster and gauge read 18", I then put this line to the canister on firewall and trunk latch worked perfectly.
With the lines hooked back up, one to firewall canister and other to Brake Booster trunk latch again doesn't have enough vacuum to pull latch. All this was done with the engine running.
Next I pulled the line from the side of Tee located on top of the Brake Booster that goes to the Storage tank located under the driver side front fender. With the engine running and my gauge plugged directly into the Tee the most my gauge would register was 1" / 2" of vacuum. My thought here was that if I was pulling 18" off hose going into the Brake Booster Tee connection I would see the same at the connection going out to Storage tank.

Supernice88

I was having a similar problem with my trunk release. I ended up taking the valve in the glove compartment apart and cleaning it and that fixed the issue (it's a pretty simple device). You are probably getting enough vacuum to the valve but the diagram in it won't seal enough to pull the latch. The canister should have one line going into it and one going out that goes to the latch in the glove box, there's another line on the latch in the glove box and that goes to the piston latch in the trunk.
As far as the brake booster I'll check mine tomorrow and let you know what I find.

Supernice88

I tested my car and found 18-20" on both sides of the tee on the brake booster and 18" on the in and out on the trunk canister tank.
When I took the hose off the tee going to the storage tank to hook up the gage there was pressure released. You might have to look into see if there is a problem with the brake booster or you have a bad storage tank that isn't holding any air. Try connecting the gage directly on the tee going to the tank by itself and see what you get for a reading.
Same thing with the trunk release, you are loosing pressure after the canister.

woodeye47

Here is how things are currently set up. Vacuum line leaves bottom rear of Carburetor goes through a check valve and then a Tee leading to the Trunk Release canister on firewall. Continuing on from this Tee to the Tee on top of the Brake Booster. There is then a hose continuing on to Brake canister under fender.
This morning I jumped around the Brake Booster Tee with a piece of tubing and going direct to the Brake canister under fender. When I pulled the hose from the Trunk canister it had accumulated vacuum but when hooked back up it was not enough to trip trunk release. I then went ahead and pulled valve in glove box, cleaned valve and put light lubrication on seal cups, tried again and nothing. Later I measured 8" at the tee leading directly to the canister. The distance from tee in main line to the Trunk canister is 6 1/2". I knew from previous work on the trunk latch that 10" is not enough to release the latch.
I now do believe I will go back to individual lines going forward. One for Trunk canister and then separate for Break Booster. I like you am pretty sure there is an issue with the Brake Booster needing addressed. Thank you for the testing you did on your on your car.

Oldsfan

I don't think the power trunk vacuum should involve the brake booster vacuum at all. I think the trunk vacuum tees off of the advance vacuum line from the front of the carb.

woodeye47

Oldsfan, yes I agree. Where I started was the power trunk latch quit working. Turns out lack of enough vacuum was the issue. In tracking this issue it ultimately turns out to be the Brake Booster. On my car the Booster and the trunk are fed with separate lines coming from a brass Tee at the rear of carburetor. I have removed Booster now and I think the culprit is the 3/4" hose from bottom of Tee connecting into the inside of Booster. I will see tomorrow. I did find out that by going straight to by Brake Vacuum tank, by passing the Booster I get 20" at idle and the trunk latch operates well. On my car it takes at least 14" of vacuum to open trunk latch.

woodeye47

Yes I am beginning to see that it doesn't take much of a leak to cause real issues. Having a remote trunk latch is pretty important for me as this car has a Continental Kit making access to the mechanical key lock very difficult to operate. Not impossible but really tight. I think I am getting there and it is probably good to find the Booster issue in the garage and not while moving the car about. Thanks for sharing

droldsmorland

Manually actuate the latch at the switch with a mity vac or another vac source. Does the trunk release? Yes, then the prob is from the switch back into the engine compartment.
Is the line free of obstructions/pinches from the switch to the latch?

I have found a few vac trunk releases that were weak due to a crushed vac line under the seats or in other locations. I had one that was bad from the factory The metal hose guide on the foot well was screwed to the floor with the hose pinched between it and the floor.

woodeye47

OK to kind of let everyone know where this all finally ended up. The Booster was where the vacuum issue was an d the way I was hooked up effected the power trunk release activation or lack of. Took booster out and tried several things to no avail. Finally I ran out of thing to try. I called and got in contact with a man at Harmon Classic Brakes in Georgia and after his suggestions and a third phone call the problem was tracked to an item referred to as a Reaction Diaphragm Support Plate. After removing it everything fell into place and works splendidly. I can't say enough positive things about my experience with Harmon Classic Brakes. Thanks to everyone for your help and suggestions.

droldsmorland

Glad to hear problem solved.
Thanks for circling back and closing the loop.

Supernice88

Good to know you got it resolved.