Vacuum hoses
Thread Starter
Burning Brakes
Joined: Apr 2009
Posts: 807
Likes: 2
From: VIRGINIA BEACH VIRGINIA
Vacuum hoses
I am going to tackle all the gremlins in my vacuum hoses this winter. I have problems with my headlights coming up slow (probably the relays) and sometimes my vents don't open or close and there is a serious bubba vacuum home mess in the engine compartment.
What hoses should be attached to the engine and what ones to the carb?
Right now I have 4 separate lines going to the engine (vents, lights, transmission, and cruise)
On the carb I have vacuum advace, brakes and one other that I can't remember here from my desk.
I have all the headlight diagrams so i will clean that up, how about the other hoses. What should be T ed together and what should go to the carb and what to the engine individually?
I don't have any of the emissions crap on there and it is a 79 L48 pretty much stock engine.
Thanks
Dan
What hoses should be attached to the engine and what ones to the carb?
Right now I have 4 separate lines going to the engine (vents, lights, transmission, and cruise)
On the carb I have vacuum advace, brakes and one other that I can't remember here from my desk.
I have all the headlight diagrams so i will clean that up, how about the other hoses. What should be T ed together and what should go to the carb and what to the engine individually?
I don't have any of the emissions crap on there and it is a 79 L48 pretty much stock engine.
Thanks
Dan
Melting Slicks
Joined: Jun 2005
Posts: 2,239
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From: Palatine, Peoples Republic of Illinois
St. Jude Donor '09-'10-'11-12-'13-'14-'15-'16-'17-‘18
NCM Sinkhole Donor
I believe all the actuator vacuum comes off the manifold either directly or through the vacuum canister. The only carb vacuum is for timing advance (depending on which side of that argument you're on) or for emissions. Do you have the AIM for your year? You will need it for hose routing other info. Good Luck.
Team Owner
Joined: Jun 2000
Posts: 38,923
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From: Southbound
Cruise-In II Veteran
Purchase the assembly instruction manual (AIM) for your car. The AIM shows all the hoses (vacuum, emissions, ventilation, etc), all the correct color codes, and where they connect.
Team Owner
Joined: Jun 2000
Posts: 38,923
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From: Southbound
Cruise-In II Veteran
Safety Car
Joined: Sep 2005
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From: Southeast, Tennessee
St. Jude Donor '09 thru '26
you can check several of the parts suppliers web sites. i know that dr rebuild and keen both have exploded diagrams of the system. the replacement (repair) kits are all color coded and make replacement and installation pretty easy. the vacuum source will be somewhere behind the carb either from the manifold or from the carb itself (i don't remember which) and that main line (from which all other vacuum lines come) will have a check valve and an in line filter before any of the line branches off. rather than take a chance on any of my vacuum lines (i could tell they were pretty old when i got my car, and was afraid they could have even been original), i replaced them all (not hard at all). at that point, any problems had to be in the actuators themselves or the relays. made the job that much easier to me by eliminating the bulk of potential problems by replacing all the lines, filter and check valve. it is almost impossible to find a weeping line (not broken or cracked badly enough to hiss) and even if the line looks good it may not be. even the ends of the lines that go over the various nipples on the relay or the actuator will give you problems if they have dried out and are cracked around the ends.
Team Owner
Joined: Sep 2006
Posts: 31,198
Likes: 4,287
From: Westminster Maryland
Hi Dan,
Working on the vacuum system can get expensive pretty quickly if you start replacing parts to find out what's wrong.
Perhaps you should first buy a Trouble Shooting Guide, (I like the one from Dr. Rebuild), and a vacuum pump with a gauge (like a Mity-Vac). This will allow you to test all the components to see what's working and what isn't.
You have it easy.... you don't have the wiper door system to deal with.
Good Luck!
Regards,
Alan
Working on the vacuum system can get expensive pretty quickly if you start replacing parts to find out what's wrong.
Perhaps you should first buy a Trouble Shooting Guide, (I like the one from Dr. Rebuild), and a vacuum pump with a gauge (like a Mity-Vac). This will allow you to test all the components to see what's working and what isn't.
You have it easy.... you don't have the wiper door system to deal with.
Good Luck!
Regards,
Alan
Thread Starter
Burning Brakes
Joined: Apr 2009
Posts: 807
Likes: 2
From: VIRGINIA BEACH VIRGINIA
Thanks to all. I will check out Dr. Rebuild. Replaced all the headlight hoses and I have a feeling the problem is the heater/vent hoses under the dash. I will get the vacuum gage and check them and see what happens.
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Racer
Joined: Feb 2007
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From: Buena Vista Colorado
Posted by dgood:
Easy to check. If your vacuum system is stock, all vacuum for the climate control system comes through a rather small, black vacuum hose that leads from a "T" in one of the headlight vacuum hoses, OR from a "T" in a cruise control system vacuum hose in the engine bay, and goes through a 3-hole firewall grommet behind the passenger side of the distributor. Just disconnect that small hose at the "T" and cap that port on the "T". This removes the climate control system and its leaks, if any, from the vacuum system. Now, start your car and see if your headlight problem is still there. If not, your feeling is correct. If your headlights are still very slow, then you've proven the problem is NOT in the climate control part of the vacuum system.
If your climate control system has been working OK, I doubt that any leaks it may have are causing your headlight problem.
Here's a link to a sticky on I wrote that might help with your headlight vacuum problems:
How Your Headlight Vacuum System Works
...I have a feeling the problem is the heater/vent hoses under the dash.
If your climate control system has been working OK, I doubt that any leaks it may have are causing your headlight problem.
Here's a link to a sticky on I wrote that might help with your headlight vacuum problems:
How Your Headlight Vacuum System Works
Thread Starter
Burning Brakes
Joined: Apr 2009
Posts: 807
Likes: 2
From: VIRGINIA BEACH VIRGINIA
78 thanks. I printed the sticky out. I have to get some free time and money so I can check the vacuum hoses for the climate control. Those hoses are still original. My light relays and actuators are orginal also. I have rebuilt the actuators and I saw a link here somewhere that explains how to rebuild the relays. I will try that and then hit a vendor up for some new ones.