Intake vaccum

[Emahlum]

Hello, looking for advice on my 1985 ford bronco ii 2.8 cologne v6 with intake vacuum I have 2 ports on the back of the intake manifold for vacuum lines and looked into diagrams and online and cannot find anything just wondering if anybody could help me figure out what the 2 vacuum ports are for? Was thinking one was for brake booster vacuum but I am unsure. Thank you in advance.

 

[tw205]

I have a couple a three of them in the corral. 2 have been duraspark’d. Does yours still have factory distributor/ ignition / carburetor? There should be vacuum for the brake booster, PCV, EGR and if you have an automatic transmission, vacuum for the modulator. I’d have to look for sure but I think the brake booster is actually off the back of the carb. I can get you pictures or more detailed info in the light of day tomorrow.

 

[Emahlum]

So it has a Holley 390cfm with a Holley distributor and Holley external coil with plug wires but same starter selonoid. And looked at a 2.8 year down intake manifold looks the same as a offenhauser dual port intake

 

[Emahlum]

Sorry not Holley a Mallory distributor

 

[Emahlum]

It has a manual transmission as well

 

[tw205]

Nice. Well it’s not unusual to have unused ports and since yours is converted you should just plug the ones you don’t need. One for brakes one for PCV and you should be good.

 

[Emahlum]

Nice. Well it’s not unusual to have unused ports and since yours is converted you should just plug the ones you don’t need. One for brakes one for PCV and you should be good.

That’s what I was thinking so the pcv is the one off the valve cover? I have the booster hose I think but I tried finding a new one to order but couldn’t find one to buy.

 

[tw205]

Yes the pcv is on the valve cover. It needs vacuum to keep the engine from building up internal pressure and blowing oil out your seals. I doubt the preformed hose for the brakes is still available. Take the old one into the auto parts store and get a new length of hose. It will be flexible enough to get you there.

 

[Emahlum]

Yes the pvc is on the valve cover. It needs vacuum to keep the engine from building up internal pressure and blowing oil out your seals. I doubt the preformed hose for the brakes is still available. Take the old one into the auto parts store and get a new length of hose. It will be flexible enough to get you there.

Where could I find a fitting for the booster? Also the pcv hose should be routed to the rear intake vacuum port you think correct?

 

[tw205]

Factory has the pcv hose routed to the back of the carb but the intake manifold will work as well if your new carb doesn’t have a port.
Which fitting do you need for the brake booster?The valve on the booster?

1985 FORD BRONCO II 2.8L 171cid V6 Power Brake Booster Check Valve | RockAuto

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[Emahlum]

I got the brake hose fitting made up and wondering if the pcv valve should be rain too the valve cover port on the engine or where that is run too?

 

[Uncle Gump]

PCV should go in the valve cover... then connected to manifold vacuum source. The opposite valve cover should have a breather to allow fresh air into the engine.

 

[Emahlum]

So I just took a look at the truck tonight got the booster hooked up for vacuum but the pcv vent on passenger side is there. but don’t have a vacuum port for the pcv off the intake manifold. The vent has a upper tube that is like 1/4 diameter and the lower port is a 3/8 wondering if that port is for the vacuum off the intake?