1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

Vacuum Lines And Where To Start

Discussion in 'Intermediate CJ-5/6/7/8' started by Cull, Aug 2, 2022.

  1. Aug 2, 2022
    Cull

    Cull New Member

    Georgia
    Joined:
    Jun 7, 2022
    Messages:
    4
    Hello.
    After 27 years of wanting a jeep, I finally bought one a couple months ago. Seems like a pretty good one, for what I know about them (not a lot), and the family and I have a great time putting along in it. I have young kids, and they both love it. First day of school was pretty awesome for them eating a honeybun in the back seat while watching the sunrise. Then a short drive to get dropped off at school. Outta be a great memory.

    Here is what I know (or at least think I know) about the jeep:
    1978 CJ5
    258 I6
    T18 transmission
    Dana 20 transfer (pretty sure)
    Rear end- AMC
    front end- I have no idea

    I did change the spark plugs, oil and oil filter. I can’t remember the brand of plugs I used, but I know I changed the gap (maybe it was 40 ?). I used a wix filter, and the fresh oil I put in it was rotella T4 15-40 (which did help with oil pressure, until it warms up pretty good, then it’s basically back down to zero at idle, and probably 40 as I’m going down the road).

    It was pretty doggy when I first drought it home. Did the plugs and air filter (lawnmower type air filter since the housing was gone). That didn’t help. I noticed some vacuum plugs were basically shot, so I replaced all of the vac plugs I could see, and tgat made a great improvement on how it runs.

    Now the question- what vacuum lines should I have? What lines should I have hooked up to what?

    SO MANY QUESTIONS. But let’s start with vacuum lines.

    I have several photos I can share, but I think I have to have a minimum number of posts before I can put them in???
     
  2. Aug 25, 2022
    Cull

    Cull New Member

    Georgia
    Joined:
    Jun 7, 2022
    Messages:
    4
    Bumping this, trying to find some guidance on vacuum lines and if I need them or not.
     
  3. Aug 25, 2022
    Cull

    Cull New Member

    Georgia
    Joined:
    Jun 7, 2022
    Messages:
    4
    What vacuum lines should I have? What lines should I have hooked up to what?

    I have several photos I can share, but I think I have to have a minimum number of posts before I can put them in???
     
  4. Aug 25, 2022
    Buildflycrash

    Buildflycrash More or Less in Line. 2024 Sponsor 2022 Sponsor

    Gulf Breeze FL...
    Joined:
    Jun 5, 2007
    Messages:
    3,559
    One line to the distributor/vacuum advance for sure.
    Maybe there is PCV. Power brakes not likely.

    The next post will say to buy the shop manual (good advise). Maybe even give you a link.
     
  5. Aug 25, 2022
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

    Grand Mesa, CO
    Joined:
    Aug 13, 2006
    Messages:
    1,318
  6. Aug 25, 2022
    Buildflycrash

    Buildflycrash More or Less in Line. 2024 Sponsor 2022 Sponsor

    Gulf Breeze FL...
    Joined:
    Jun 5, 2007
    Messages:
    3,559
    /\ I knew it /\
     
  7. Aug 25, 2022
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

    Grand Mesa, CO
    Joined:
    Aug 13, 2006
    Messages:
    1,318
    I couldn't let your prediction go un-noticed! :beer:
     
    Buildflycrash likes this.
  8. Aug 25, 2022
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
    Messages:
    5,593
    Some of our members that are connected to the last generation of CJs (Tim comes to mind, but there are others) might be of help as 1978 is really moving solidly into the last generation of cj5s with full AMC design etc....I also think by 1978, emissions requirements really started to play a role in sucking some life out of the engines and adding in complicating factors. As mentioned above, getting a factory service manual (FSM) will be of help, especially with regard to emissions and all the vacuum lines. And by 1978, I'd be looking for a FSM that is specific to that year as emissions stuff started to get added each and every year, or at least get 1976 and after as that was the beginning of the last generation of CJ5s....Stuff from 72-75 ('intermediate' cj5) will be a bit out of date.

    Also, if its mostly original (1978 258/T18/D20 combo is VERY sweet - wasn't 1978 still running a D44 rear axle? front axle would expect to be a D30, but things get changed), then getting the vacuum and emissions stuff back to fully functional original configuration is great....but as many of these jeeps have had previous owners that have made their own 'improvements' you might find so much of the emissions stuff has been messed with, removed or modified, that stripping it down to as simple as possible might be the right route (assuming you don't have local emissions testing and inspections). I am not sure when the emissions Carter BBD carbs started on cjs (I had one on my 84cj7 with the 'automatic' altitude mixture adjustment) - maybe it was in use by 1978? If you want lots of reading and quite the rabbit hole of information and mis-information, you can google 'nutter bypass' as an option to remove most of the emissions stuff - again not sure if this applies to 78 jeeps or not.
     
New Posts