Under hood question

[B.M.]

I dont think it actually has anything to do with the engine,but on my 81 there is a round thing that looks like a ball with a vacum line and another line coming off it right above the a/c box.Can anybody tell me what this is?

 

[High Country Z]

Sounds like a vacuum reservoir.

 

[CorkyE]

Yep, vac reservoir for the heat/air system. It holds vacuum so you can change from heat/vent/air condition when under load and vacuum is weak.

 

[B.M.]

Yep, vac reservoir for the heat/air system. It holds vacuum so you can change from heat/vent/air condition when under load and vacuum is weak.

I took the a/c out so do i still need this then?It is right in the spot i want to mount my msd box so if i dont need it there anymore that will work out great.

 

[CorkyE]

I don't run one, then again I don't drive much where I need to switch from heater to vent, etc. You will need to hook up the small line to a vacuum source if you want to switch from vent to heater to defrost, etc.

 

[B.M.]

Cool thanks,yeah i wont be driving this car in the cold anyway,so the most i would ever need to turn on would be the defrost if it would be raining or something.Thanks again.

 

[z28rod]

vac reservoir for the heat/air system controls, leave it so your controls work......

 

[Twisted_Metal]

vac reservoir for the heat/air system controls, leave it so your controls work......

^+1

I think it's kind of fun to find cars where these have been removed.

When you hook up the vacuum line again..... Junk comes flying out of the dash where no air has been blown for a decade!

Even though the owner has a mess to clean up... They are usually thankful to have some control about where the air blows!

 

[CorkyE]

^+1

I think it's kind of fun to find cars where these have been removed.

When you hook up the vacuum line again..... Junk comes flying out of the dash where no air has been blown for a decade!

Even though the owner has a mess to clean up... They are usually thankful to have some control about where the air blows!

I have mine hooked to full vacuum, it still works, I can still switch controls. Sometimes just have to do it when decelerating to get a higher vacuum signal, but it still works.

Because you remove the in line reservoir doesn't mean it won't still work - it just needs a vacuum source. I hooked a reservoir can in line with my brakes; will they quit if I remove the can? No - but they wont work as well in my case. Same difference...

 

[falloutboy]

Funny thing is -- I had this question a few month ago.
No I have discarded it. Cause it was only connected to engine vacuum but no nothing else.

And all my heater / vent and so on functions work properly.
Why is that?