AMC Eagle Den Forum

The Mighty 258 => Emissions/Vacuum Systems => Topic started by: shanebo on April 19, 2011, 12:23:17 AM

Title: 4x4 vaccum diagram?
Post by: shanebo on April 19, 2011, 12:23:17 AM
when I disassembaled my eagle half the vaccum lines related to the 4wd were either broken or disconnected....If I recall theres only 3 lines off the switch...Im just curious as to how they hook up to to the vaccum diaphragms on the front axle and the T-case...Is there a diagram here on the nest of the proper routing of the 4x vaccum lines.....I may delete the front vac motor and make her shift on the fly!
Title: Re: 4x4 vaccum diagram?
Post by: IowaEagle on April 19, 2011, 06:21:50 AM
The AMC Eaglepedia have some.
Title: Re: 4x4 vaccum diagram?
Post by: BenM on April 19, 2011, 03:09:50 PM
The real problem is finding the vinyl or poly hard vacuum lines. You may have to order them, as I've never seen them at a parts store, except in black and short sections.
Title: Re: 4x4 vaccum diagram?
Post by: shanebo on April 20, 2011, 12:38:52 AM
Thats been a concern of mine....However I know from driving truck in the past, alot of stuff is controlled via air. If memory serves There were air lines about the size of the ones in the eagle that ran from various switches in the dash of the Freightliner I used to drive....Im thinking the first place to look will be at the Colorado Kenworth parts dept.....Lets hope Im right.
Title: Re: 4x4 vaccum diagram?
Post by: AMC1 on July 02, 2021, 04:02:42 PM
I recently needed to refer to a drawing I made some time back. Maybe someone else may find it useful.
Title: Re: 4x4 vaccum diagram?
Post by: rmick on July 02, 2021, 10:46:44 PM
http://amceaglesden.com/guide/Select_Shift
Title: Re: 4x4 vaccum diagram?
Post by: Mr_Roboto on July 03, 2022, 10:43:13 AM
A few questions,

1-where is the vacuum resivoir typically at?
2-where does the line for the awd systems connect in?
3-does the resivoir connect straight to engine vacuum on the other side?

The systems underhood were significantly altered and I am trying to piece things back together. It looks as if the red/green/white lines are still there.
Title: Re: 4x4 vaccum diagram?
Post by: Illeagle1984 on July 03, 2022, 12:01:11 PM
1. The vacuum reservoir on mine is bolted to the driver side inner fender, between the coolant reservoir and shock tower.  Most people would say it looks like a coffee can.  There is a pic of my engine bay here for reference: https://forums.amceaglesden.com/index.php?topic=47004.msg362957#msg362957 (shameless plug I know lol) If you flip the pic right side up, it's the little round can in the lower right of course.

2.  I'm not sure exactly where.  I'm headed to the shop later today, I can see where mine are plumbed in.  I can say that I disconnected mine and ended up hooking it back up.  Without it, the transfer case would neutral out sometimes after an extended high-RPM blast.  Your results may vary, I'm sure I have less vacuum available with my big ol' Holley on top.

3. Yes.  See #2, I'll check later where they are routed.

If you're looking for other ideas to get you by, I thought I saw somewhere here where a guy made a manual shift lever like Jeeps have for the t-case.  Or ya could just disconnect the vacuum motor and keep it in 4wd all the time.  Won't hurt a thing as long as your tires are all the same...
Title: Re: 4x4 vaccum diagram?
Post by: Mr_Roboto on July 03, 2022, 12:25:10 PM
Thanks!

I think I will wind up in the same boat honestly. I yave a 500cfm afb and supposedly a cam. Mine is a bit different than your coffee can but same idea.

There is a small line going into the car, but I think that is the heater water valve.
Title: Re: 4x4 vaccum diagram?
Post by: MIPS on July 03, 2022, 09:37:49 PM
Mine is a plastic canister that bolts on the passenger inner fender below the ignition module. It has a large diameter hose run over the valve cover and to a port for Manifold vacuum close to the firewall.
Title: Re: 4x4 vaccum diagram?
Post by: Illeagle1984 on July 05, 2022, 11:54:57 AM
I keep forgetting these cars changed a lot in their short timespan.  Mine is an 84.  The EVAP charcoal canister was right below it; black plastic can a lot like what MIPS was describing.  I looked where my hoses are routed; it took a little digging since they were both wrangled into the main wiring loom.  The larger one went to a port on the rear of the intake manifold, so straight up direct vacuum.  The other went to a check valve (those little round disc things you may see in various places with a line plugged into each side of the flat part) on the passenger side.  The other side of the check valve was the black vacuum line going to the 4wd block down by the starter.

Hope this helps. :) I did a major vacuum line delete so there may have been a tee eliminated somewhere.
Title: Re: 4x4 vaccum diagram?
Post by: Mr_Roboto on July 05, 2022, 02:22:59 PM
I think that "vacuum block by the starter" is the answer I'm looking for, and that the line is non existent on my car currently. I was hoping to save crawling under to find it, but I think that it was expected.
Title: Re: 4x4 vaccum diagram?
Post by: MIPS on July 05, 2022, 03:02:34 PM
It's a set of steel lines that run to the back (and front on earlier models) to simplify a lot of plumbing and is bolted to.....huh I seem to of forgotten.  :o
Anyways if the transmission or engine was dropped it would of needed to be removed and if someone modified the TC to be always-on it was removed and tossed.