Tree valve, how to check

[Ralph A.]

I am searching for a vacuum leak on my 71. Can someone tell me how to check the tree valves. I have 3 of them out of the car.
Here is what I have done.
If I put pressure to the center stem and cover the stem farthest from the valve air leaks out of where the valve stem sticks out of the tree. I think there was a filter of some sort on that end. Is air supposed to come out?
The tree under the right fender leaks more air than the headlight trees. If no air is to come out then I will get 3 new trees.
Thanks in advance
Ralph

[Wayne P.]

Re: Tree valve, how to check

That's a filter.

[Ralph A.]

Re: Tree valve, how to check (Confused)

I figured that, but is air supposed to flow freely when a vacuum or pressure is applied at the center stem? I thought this was a sealed system and the tree valve switched between the center and either side outlets. I fair flows thriught this end then it seams you will never achieve the pressure need to activate the actuators.
Please elaborate.
RA

[Patrick H.]

Re: Tree valve, how to check

Ralph,

The Dr. Rebuild book describes how to properly test the valves. I don't recall the exact method (my book isn't handy) but in a nutshell I believe the answer is no, air is not supposed to be able to flow out of the filter end.

These valves aren't cheap, but I've replaced all 3 on my 71 and Dad's 72 due to leaking. It made a big difference. For whatever reason, all 3 on my 72 seem to work just fine.

Patrick