Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Round black vaccuum thing

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Suffergauge, Dec 16, 2002.

  1. Suffergauge

    Suffergauge 1/2 ton status

    Joined:
    Aug 1, 2002
    Posts:
    153
    Likes Received:
    0
    Location:
    Olympia, Wa.
    I know this is supposed to be for my heater controls. When I got my k5, none of the controls were hooked up. I only have one vaccuum line that runs from the firewall to this vaccuum ball. I found two nipples to plug it into. So I am imagining that it needs a vaccuum source. Does this source come rom the manifold / carb? If that is the case then easy fix and I have defrost again. /forums/images/graemlins/thumb.gif
    Thanks,
     
  2. POWERMAD

    POWERMAD 1/2 ton status

    Joined:
    Mar 4, 2001
    Posts:
    3,466
    Likes Received:
    0
    Location:
    Oregon
    plug it straight into manifold vacuume
     
  3. R72K5

    R72K5 Banned

    Joined:
    Mar 5, 2001
    Posts:
    8,905
    Likes Received:
    0
    Location:
    central IL
    what happenes if your heater controls int he dash still wont switch form vent to floor to windshield, still ?
     
  4. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

    Joined:
    Dec 15, 2002
    Posts:
    15,139
    Likes Received:
    565
    Location:
    Iowa
    The round ball on the firewall that you speak of is just a vaccum resevoir/isolator. Keeps the vaccum system under the dash seperate from the engine vaccum except when it charges. If your controls will not change from vent to heat to defrost then you have a different problem. Unfortunately under the dash. There are vaccum actuators on the heater box that controls a door which directs the hot air up/defrost, down/heat etc. If this vaccum actuator is leaking it will not change the position of the door. Also the line to the actuator could simply be disconnected or leaking. Hope I helped.
     
  5. Stoopalini

    Stoopalini 1/2 ton status

    Joined:
    Oct 17, 2000
    Posts:
    999
    Likes Received:
    0
    Location:
    Austin, Texas
    If air is coming out of the defroster, vents, and floor all at the same time ... no matter what the setting is on ... then it could be a vacuum line under the hood.

    There is a line that comes out on the passenger's side and goes to a T behing the carb/manifold. This hose was leaking on mine, and I had the same problem.

    Thomas.
     
  6. Suffergauge

    Suffergauge 1/2 ton status

    Joined:
    Aug 1, 2002
    Posts:
    153
    Likes Received:
    0
    Location:
    Olympia, Wa.
    How can it charge without a vaccuum source? I only have one line going to the canister. Two plugins tells me there should be another line. Am I wrong?
     
  7. Stoopalini

    Stoopalini 1/2 ton status

    Joined:
    Oct 17, 2000
    Posts:
    999
    Likes Received:
    0
    Location:
    Austin, Texas
    The black canister is there to provide vacuum when the manifold vacuum equalizes (like at high RPMs). That's why the previous poster referred to it as a vacuum reservoir.

    At idle, you should be able to switch from defroster, to vents, to floor even if the black canister wasn't hooked up at all.

    If you only have one vacuum line coming from the firewall, you could hook it straight to manifold vacuum, but it would loose some of it at high RPMs. You should run it to that ball thing, and then run another line from it to a port on the intake manifold.

    If you don't have any other vacuum lines under the hood, then there must be vacuum caps around on the manifold. Find one that'll fit a line from it to the reservoir, start the truck, take the cap off and feel for suction. If it has suction, then hook the line to it.

    Thomas.
     
  8. Muddytazz

    Muddytazz 1 ton status

    Joined:
    Jun 30, 2002
    Posts:
    20,073
    Likes Received:
    0
    Location:
    Salem, Or.
    One line (smaller one) goes through the firewall to the heater control, the other line (bigger one) goes to the intake manifold for the vacuum source.
     
  9. Suffergauge

    Suffergauge 1/2 ton status

    Joined:
    Aug 1, 2002
    Posts:
    153
    Likes Received:
    0
    Location:
    Olympia, Wa.
    Since it hasn't been properly hooked up in who knows how long, the res. may be empty? I will hokk it up and see where my troubleshooting will go from there. Thanks for all the info guys. /forums/images/graemlins/thumb.gif
     
  10. Suffergauge

    Suffergauge 1/2 ton status

    Joined:
    Aug 1, 2002
    Posts:
    153
    Likes Received:
    0
    Location:
    Olympia, Wa.
    Sweet it works like a champ! /forums/images/graemlins/pimp1.gif
     
  11. Stoopalini

    Stoopalini 1/2 ton status

    Joined:
    Oct 17, 2000
    Posts:
    999
    Likes Received:
    0
    Location:
    Austin, Texas
    Great /forums/images/graemlins/laugh.gif Glad you got it fixed up.

    FYI: In reality, the reservoir should be more than empty ... because it just stores vacuum /forums/images/graemlins/wink.gif LOL!
    The only way the reservoir can go bad is if it gets a hole/crack in it.

    Thomas.
     

Share This Page