yet another vacuum question

[albertv78]

Sorry guys after much searching on this forum I'm still confued. I'm adding a brake booster to my 1970 F100 w/302 california emmissions. On the rear of my engine I found the vacuum tree (first pic) with a line going to the C4 modulator. Can I replace that tree with a straight 3/8 vacuum fitting and put a "T" to feed vacuum to the C4 modulator and brake booster? I thought I found another vacuum port but it was connected to one of those vacuum switch things (second pic) so I'm guessing its at water passage and not a vacuum source (third pic), right? I'm gonna plug that open hole since nothing was connected to that vacuum switch thing anyway. Btw on the third pic what is that sensor thing on the right side of the pic for? It doesnt look like its plugged in to anything but I'd like to know what it is before I toss it.
Thanks,
Albert

[fordman]

plugging the water port is fine. that is a emissions vacuum swithc. as far as making a tee you can do that with no problem. or if you want find a pipe plug in the intake that leads to intake vacuum and use that. as far as the last sensor. i dont know. i am not familiar with older 302 sensors. it reminds me of a water temp sensor of some sort.

[FORDification]

Sorry guys after much searching on this forum I'm still confued. I'm adding a brake booster to my 1970 F100 w/302 california emmissions. On the rear of my engine I found the vacuum tree (first pic) with a line going to the C4 modulator. Can I replace that tree with a straight 3/8 vacuum fitting and put a "T" to feed vacuum to the C4 modulator and brake booster?

Well, yeah you could....but it would look jury-rigged IMO. And you probably wouldn't find a tee that's going to be small on one side for the vacuum modulator and large on the other for the brake booster. If you're going to do it, do it right. I can't tell from your picture, but your existing vacuum tree looks just like mine:



If so, you simply need to remove that large plug and screw in a 3/8" (?) vacuum nipple into it to connect the booster hose to.

I thought I found another vacuum port but it was connected to one of those vacuum switch things (second pic) so I'm guessing its at water passage and not a vacuum source (third pic), right? I'm gonna plug that open hole since nothing was connected to that vacuum switch thing anyway.

That is essentially part of your 'California emissions' equipment. It's called the 'distributor vacuum control valve', and is incorporated in the distributor vacuum advance supply line to provide advanced ignition timing under prolong idling conditions. The advance ignition timing causes an immediate increase in engine speed, which will continue until the engine temperature returns to normal. While you don't necessarily need it, if you want your emissions set-up to remain intact, you'll need to leave it and replace the missing vacuum lines. Does your engine have a single or dual vacuum advance?

Btw on the third pic what is that sensor thing on the right side of the pic for? It doesnt look like its plugged in to anything but I'd like to know what it is before I toss it.

That's your temperature sending unit. I don't think tossing it would be a good idea, unless you're planning on adding an aftermarket temperature gauge.

[albertv78]

Thanks for the help guys. My distributor has a single advance and I'm removing the smog stuff. Are there ussually two of those vacuum temp switches on a engine? I remember removing one off the front of the engine on or near the upper water outlet. Anyways.. I'm gonna try to tap into the existing vacuum tree first as Keith suggested. If that doesn't work I'll go the other route with this "T", it's 3/8-3/8-1/4.

Thanks,
Albert